dwa

adapters/bukkit/plugin/src/main/java/art/arcane/iris/Iris.java

@@ -255,19 +255,20 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
     }
 
     public static void msg(String string) {
-        try {
-            getSender().sendMessage(string);
-        } catch (Throwable e) {
         try {
             Iris plugin = instance;
-                String tag = plugin == null ? "" : plugin.getTag();
             ComponentLog.logMarkup(
                     plugin,
                     Logger.getLogger("Iris"),
-                        "[Iris] ",
+                    logPrefix(plugin),
                     Level.INFO,
-                        tag + string,
+                    string,
                     null);
+        } catch (Throwable e) {
+            try {
+                Iris plugin = instance;
+                String plainPrefix = ComponentText.legacy(logPrefix(plugin)).plain();
+                Logger.getLogger("Iris").log(Level.INFO, plainPrefix + IrisLogging.clean(string));
             } catch (Throwable inner) {
                 System.err.println("[Iris] Failed to emit log message: " + inner.getMessage());
                 inner.printStackTrace(System.err);
@@ -561,15 +562,20 @@ public class Iris extends VolmitPlugin implements Listener, ReloadAware {
 
     private static void diagnostic(Level level, String message) {
         String line = IrisLogging.clean(message);
+        Iris plugin = instance;
         ComponentLog.log(
-                instance,
+                plugin,
                 Logger.getLogger("Iris"),
-                "[Iris] ",
+                logPrefix(plugin),
                 level,
                 ComponentText.literal(line),
                 null);
     }
 
+    private static String logPrefix(Iris plugin) {
+        return plugin == null ? "[Iris] " : plugin.getTag();
+    }
+
     /**
      * @return false when the bootstrap was aborted (unsupported server version); the caller
      * must bail out of onEnable without touching any further setup.

adapters/bukkit/plugin/src/test/java/art/arcane/iris/IrisDiagnosticLogLevelTest.java

@@ -13,10 +13,8 @@ import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 /**
- * Core states a severity on every message it logs and the modded adapters honour it. On Bukkit the same
- * message used to become a coloured console line, which the server logs at INFO, so no core warning ever
- * appeared in a WARN-level scan of logs/latest.log - including the orphaned-world-storage reports the
- * bootstrap replays there specifically for operators to find.
+ * Core states a severity on every message it logs and the modded adapters honour it. Bukkit must preserve
+ * that severity through the shared component logger so diagnostics remain discoverable in logs/latest.log.
  */
 public class IrisDiagnosticLogLevelTest {
     @Test
@@ -26,25 +24,16 @@ public class IrisDiagnosticLogLevelTest {
     }
 
     @Test
-    public void informationalAndDebugMessagesStayOnTheConsolePath() {
+    public void informationalAndDebugMessagesStayOnTheInformationalPath() {
         assertNull(Iris.diagnosticLevel(LogLevel.INFO));
         assertNull(Iris.diagnosticLevel(LogLevel.DEBUG));
     }
 
-    /**
-     * Console sender output reaches the terminal but not the instance's logs/latest.log, which is the only
-     * log most operators read after the fact. A handful of lifecycle lines go to the plugin logger instead.
-     */
     @Test
     public void lifecycleNoticesReachThePluginLoggerAtInfo() {
         assertEquals(Level.INFO, Iris.diagnosticLevel(LogLevel.NOTICE));
     }
 
-    /**
-     * A warning raised by the adapter is the same kind of thing as a warning raised by core. Routing one
-     * through the plugin logger and the other through the console sender makes the level depend on which
-     * side of the SPI the call happened to be written on.
-     */
     @Test
     public void adapterSideWarningsCarryTheSameSeverityAsCoreWarnings() throws Exception {
         String source = Files.readString(Path.of("src/main/java/art/arcane/iris/Iris.java")).replace("\r\n", "\n");
@@ -70,6 +59,16 @@ public class IrisDiagnosticLogLevelTest {
         assertTrue(diagnostic, diagnostic.contains("ComponentText.literal(line)"));
     }
 
+    @Test
+    public void informationalMessagesUseTheSharedComponentLogger() throws Exception {
+        String source = Files.readString(Path.of("src/main/java/art/arcane/iris/Iris.java")).replace("\r\n", "\n");
+        String message = method(source, "public static void msg(String string)");
+
+        assertTrue(message, message.contains("ComponentLog.logMarkup("));
+        assertTrue(message, message.contains("logPrefix(plugin)"));
+        assertFalse(message, message.contains("getSender().sendMessage"));
+    }
+
     private static String method(String source, String signature) {
         int start = source.indexOf(signature);
         assertTrue("method not found: " + signature, start >= 0);

core/src/main/java/art/arcane/iris/core/pack/PackRiverValidator.java

@@ -111,10 +111,10 @@ final class PackRiverValidator {
         }
 
         if (topology != null && terrain != null) {
-            double meanderStrength = doubleValue(terrain, "meanderStrength", 72D);
+            WormEnvelope wormEnvelope = wormEnvelope(terrain);
             int cellSize = integerValue(topology, "cellSize", 512);
-            if (Double.isFinite(meanderStrength) && meanderStrength > cellSize) {
-                warnings.add(path + ".terrain.meanderStrength exceeds topology.cellSize; reaches may require large cache halos.");
+            if (wormEnvelope.maximumOffset() > cellSize) {
+                warnings.add(path + ".terrain.worms maxOffset exceeds topology.cellSize; reaches may require large cache halos.");
             }
             validateTopologyComplexity(packFolder, path, topology, terrain, errors);
         }
@@ -144,8 +144,6 @@ final class PackRiverValidator {
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "routingNoiseWeight", 0D, 1024D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "flowAlignmentWeight", 0D, 1024D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "confluenceWeight", 0D, 1024D, errors);
-        PackJsonFieldChecks.validateOptionalIntegerRange(path, topology, "branchSoftCap", 1, 8, errors);
-        PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "branchChildShrinkFactor", 0D, 1D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "terrainHeightWeight", 0D, 16D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "terrainSlopeWeight", 0D, 16D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, topology, "oceanAttraction", 0D, 16D, errors);
@@ -180,8 +178,6 @@ final class PackRiverValidator {
         PackJsonFieldChecks.validateOptionalDoubleRange(path, terrain, "tunnelMouthBlend", 0D, 16D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, terrain, "tunnelFloorVariation", 0D, 8D, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, terrain, "tunnelRoofVariation", 0D, 16D, errors);
-        PackJsonFieldChecks.validateOptionalDoubleRange(path, terrain, "meanderStrength", 0D, 1024D, errors);
-        PackJsonFieldChecks.validateOptionalIntegerRange(path, terrain, "meanderSubdivisions", 1, 64, errors);
         PackJsonFieldChecks.validateOptionalDoubleRange(path, terrain, "bedRoughness", 0D, 8D, errors);
         PackJsonFieldChecks.validateOptionalEnum(path, terrain, "terminalMode", TERMINAL_MODES, errors);
         PackJsonFieldChecks.validateOptionalIntegerRange(path, terrain, "terminalTaper", 8, 1024, errors);
@@ -189,8 +185,8 @@ final class PackRiverValidator {
         validateNoiseChance(packFolder, terrain, "incision", path, errors);
         validateStyle(packFolder, terrain, "tunnelFloorStyle", path, errors);
         validateStyle(packFolder, terrain, "tunnelRoofStyle", path, errors);
-        validateStyle(packFolder, terrain, "meanderStyle", path, errors);
         validateStyle(packFolder, terrain, "bedRoughnessStyle", path, errors);
+        validateWorms(path, terrain, errors);
         double maximumChannelWidth = doubleValue(terrain, "maxChannelWidth", 10D);
         double maximumTunnelWidthMultiplier = styledRangeMaximum(
                 packFolder,
@@ -240,8 +236,7 @@ final class PackRiverValidator {
         int tileCells = integerValue(topology, "tileCells", 4);
         double siteJitter = doubleValue(topology, "siteJitter", 0.35D);
         int maxRouteReaches = integerValue(topology, "maxRouteReaches", 16);
-        double meanderStrength = doubleValue(terrain, "meanderStrength", 72D);
-        int meanderSubdivisions = integerValue(terrain, "meanderSubdivisions", 8);
+        WormEnvelope wormEnvelope = wormEnvelope(terrain);
         double maximumChannelWidth = doubleValue(terrain, "maxChannelWidth", 10D);
         double maximumBankWidth = doubleValue(terrain, "maxBankWidth", 4D);
         double maximumTunnelWidthMultiplier = styledRangeMaximum(
@@ -256,8 +251,8 @@ final class PackRiverValidator {
                 || tileCells < 1 || tileCells > 64
                 || !Double.isFinite(siteJitter) || siteJitter < 0D || siteJitter > 0.49D
                 || maxRouteReaches < 1 || maxRouteReaches > 256
-                || !Double.isFinite(meanderStrength) || meanderStrength < 0D || meanderStrength > 1024D
-                || meanderSubdivisions < 1 || meanderSubdivisions > 64
+                || wormEnvelope.maximumOffset() < 0D || wormEnvelope.maximumOffset() > 1024D
+                || wormEnvelope.maximumSegments() < 1 || wormEnvelope.maximumSegments() > 64
                 || !Double.isFinite(maximumChannelWidth) || maximumChannelWidth < 1D || maximumChannelWidth > 2048D
                 || !Double.isFinite(maximumBankWidth) || maximumBankWidth < 0D || maximumBankWidth > 2048D
                 || !Double.isFinite(maximumTunnelWidthMultiplier)
@@ -275,14 +270,187 @@ final class PackRiverValidator {
                 siteJitter,
                 maxRouteReaches,
                 maximumReachRadius,
-                meanderStrength,
-                meanderSubdivisions
+                wormEnvelope.maximumOffset(),
+                wormEnvelope.maximumSegments()
         );
         for (String violation : estimate.violations()) {
             errors.add(path + " exceeds the safe derived complexity budget. " + violation);
         }
     }
 
+    private static void validateWorms(String path, JSONObject terrain, List<String> errors) {
+        Object rawWorms = terrain.opt("worms");
+        if (!(rawWorms instanceof JSONArray worms)) {
+            errors.add(path + ".worms must be an array with at least one Perlin-worm profile.");
+            return;
+        }
+        if (worms.length() < 1) {
+            errors.add(path + ".worms must contain at least one Perlin-worm profile.");
+            return;
+        }
+        if (worms.length() > 16) {
+            errors.add(path + ".worms must contain at most 16 root profiles.");
+        }
+        Set<String> ids = new HashSet<String>();
+        Set<Long> seeds = new HashSet<Long>();
+        int profileCount = validateWormArray(path + ".worms", worms, 1, ids, seeds, errors);
+        if (profileCount > 128) {
+            errors.add(path + ".worms hierarchy must contain at most 128 profiles.");
+        }
+    }
+
+    private static int validateWormArray(
+            String path,
+            JSONArray worms,
+            int depth,
+            Set<String> ids,
+            Set<Long> seeds,
+            List<String> errors
+    ) {
+        if (worms.length() > 16) {
+            errors.add(path + " must contain at most 16 profiles.");
+        }
+        double totalWeight = 0D;
+        int profileCount = 0;
+        for (int index = 0; index < worms.length(); index++) {
+            JSONObject worm = worms.optJSONObject(index);
+            String wormPath = path + "[" + index + "]";
+            if (worm == null) {
+                errors.add(wormPath + " must be an object.");
+                continue;
+            }
+            profileCount++;
+            validateWormId(wormPath, worm, ids, errors);
+            long seed = validateWormSeed(wormPath, worm, errors);
+            if (!seeds.add(seed)) {
+                errors.add(wormPath + ".seed must be unique inside the worm hierarchy.");
+            }
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "weight", 0.000001D, 1000000D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "wavelength", 8D, 16384D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "detailWavelength", 8D, 16384D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "tortuosity", 0D, 1D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "detailTortuosity", 0D, 1D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "maxOffset", 0D, 1024D, errors);
+            PackJsonFieldChecks.validateOptionalIntegerRange(wormPath, worm, "segments", 1, 64, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "widthMultiplier", 0.125D, 8D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "bankMultiplier", 0.125D, 8D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "depthMultiplier", 0.125D, 8D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "bodyWavelength", 32D, 16384D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "bodyDetailWavelength", 32D, 16384D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "widthVariation", 0D, 0.875D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "bankVariation", 0D, 0.875D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "depthVariation", 0D, 0.875D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "roofVariation", 0D, 0.875D, errors);
+            PackJsonFieldChecks.validateOptionalIntegerRange(wormPath, worm, "branchCap", 1, 8, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "branchDecay", 0D, 1D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "confluenceMultiplier", 0D, 8D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "childChance", 0D, 1D, errors);
+            PackJsonFieldChecks.validateOptionalDoubleRange(
+                    wormPath, worm, "branchChildChance", 0D, 1D, errors);
+            totalWeight += doubleValue(worm, "weight", 1D);
+            Object rawChildren = worm.opt("children");
+            if (rawChildren == null || rawChildren == JSONObject.NULL) {
+                continue;
+            }
+            if (!(rawChildren instanceof JSONArray children)) {
+                errors.add(wormPath + ".children must be an array.");
+                continue;
+            }
+            if (children.length() > 0 && depth >= 4) {
+                errors.add(wormPath + ".children exceeds the maximum hierarchy depth of 4.");
+                continue;
+            }
+            profileCount += validateWormArray(
+                    wormPath + ".children",
+                    children,
+                    depth + 1,
+                    ids,
+                    seeds,
+                    errors
+            );
+        }
+        if (worms.length() > 0 && (!Double.isFinite(totalWeight) || totalWeight <= 0D)) {
+            errors.add(path + " total weight must be finite and positive.");
+        }
+        return profileCount;
+    }
+
+    private static void validateWormId(String path, JSONObject worm, Set<String> ids, List<String> errors) {
+        Object rawId = worm.opt("id");
+        if (!(rawId instanceof String id) || !id.matches("[a-z0-9][a-z0-9_-]{0,63}")) {
+            errors.add(path + ".id must use 1 to 64 lowercase letters, digits, underscores, or hyphens.");
+            return;
+        }
+        if (!ids.add(id)) {
+            errors.add(path + ".id must be unique inside the worm hierarchy.");
+        }
+    }
+
+    private static long validateWormSeed(String path, JSONObject worm, List<String> errors) {
+        Object rawSeed = worm.opt("seed");
+        if (rawSeed == null || rawSeed == JSONObject.NULL) {
+            return 1L;
+        }
+        if (!(rawSeed instanceof Number number)
+                || !Double.isFinite(number.doubleValue())
+                || number.doubleValue() != StrictMath.rint(number.doubleValue())) {
+            errors.add(path + ".seed must be an integer.");
+            return 1L;
+        }
+        return number.longValue();
+    }
+
+    private static WormEnvelope wormEnvelope(JSONObject terrain) {
+        JSONArray worms = terrain.optJSONArray("worms");
+        if (worms == null || worms.length() == 0) {
+            return new WormEnvelope(320D, 48);
+        }
+        double maximumOffset = 0D;
+        int maximumSegments = 1;
+        WormEnvelope envelope = wormEnvelope(worms, maximumOffset, maximumSegments);
+        maximumOffset = envelope.maximumOffset();
+        maximumSegments = envelope.maximumSegments();
+        return new WormEnvelope(maximumOffset, maximumSegments);
+    }
+
+    private static WormEnvelope wormEnvelope(JSONArray worms, double maximumOffset, int maximumSegments) {
+        double resolvedOffset = maximumOffset;
+        int resolvedSegments = maximumSegments;
+        for (int index = 0; index < worms.length(); index++) {
+            JSONObject worm = worms.optJSONObject(index);
+            if (worm == null) {
+                continue;
+            }
+            resolvedOffset = Math.max(resolvedOffset, doubleValue(worm, "maxOffset", 320D));
+            resolvedSegments = Math.max(resolvedSegments, integerValue(worm, "segments", 48));
+            JSONArray children = worm.optJSONArray("children");
+            if (children != null) {
+                WormEnvelope childEnvelope = wormEnvelope(children, resolvedOffset, resolvedSegments);
+                resolvedOffset = Math.max(resolvedOffset, childEnvelope.maximumOffset());
+                resolvedSegments = Math.max(resolvedSegments, childEnvelope.maximumSegments());
+            }
+        }
+        return new WormEnvelope(resolvedOffset, resolvedSegments);
+    }
+
     private static void validateCaves(File packFolder, String path, JSONObject caves,
                                       boolean forceGeneratedGrotto,
                                       List<String> errors, List<String> warnings) {
@@ -961,6 +1129,9 @@ final class PackRiverValidator {
         return chance == null ? defaultValue : doubleValue(chance, "chance", defaultValue);
     }
 
+    private record WormEnvelope(double maximumOffset, int maximumSegments) {
+    }
+
     record Validation(List<String> errors, List<String> warnings) {
         Validation {
             errors = List.copyOf(errors);

core/src/main/java/art/arcane/iris/engine/object/IrisRiverTerrain.java

@@ -1,8 +1,11 @@
 package art.arcane.iris.engine.object;
 
+import art.arcane.iris.engine.object.annotations.ArrayType;
 import art.arcane.iris.engine.object.annotations.Desc;
 import art.arcane.iris.engine.object.annotations.MaxNumber;
 import art.arcane.iris.engine.object.annotations.MinNumber;
+import art.arcane.iris.engine.object.annotations.Required;
+import art.arcane.volmlib.util.collection.KList;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 import lombok.experimental.Accessors;
@@ -83,18 +86,10 @@ public class IrisRiverTerrain {
     @Desc("The maximum vertical roof variation in river tunnels.")
     private double tunnelRoofVariation = 3D;
 
-    @Desc("Warps the spacing and amplitude of varied local-normal sweeps, hooks, curls, and wandering bends while preserving graph endpoints.")
-    private IrisGeneratorStyle meanderStyle = new IrisGeneratorStyle(NoiseStyle.IRIS).zoomed(512D);
-
-    @MinNumber(0)
-    @MaxNumber(1024)
-    @Desc("The total endpoint-spline and shape-personality displacement envelope in blocks.")
-    private double meanderStrength = 72D;
-
-    @MinNumber(1)
-    @MaxNumber(64)
-    @Desc("The number of straight segments used to flatten and resolve each meandering graph reach.")
-    private int meanderSubdivisions = 8;
+    @Required
+    @ArrayType(min = 1, type = IrisRiverWorm.class)
+    @Desc("Weighted root Perlin-worm families with inherited child styles for trunks and tributaries.")
+    private KList<IrisRiverWorm> worms = new KList<IrisRiverWorm>();
 
     @Desc("Modulates small river-bed height variation after the connected channel shape is solved.")
     private IrisGeneratorStyle bedRoughnessStyle = new IrisGeneratorStyle(NoiseStyle.IRIS).zoomed(96D);

core/src/main/java/art/arcane/iris/engine/object/IrisRiverTopology.java

@@ -92,16 +92,6 @@ public class IrisRiverTopology {
     @Desc("The deterministic attraction toward shared downstream nodes. Larger values form stronger tributary trees and confluences.")
     private double confluenceWeight = 0D;
 
-    @MinNumber(1)
-    @MaxNumber(8)
-    @Desc("The number of upstream children a graph node accepts before additional branches begin shrinking probabilistically.")
-    private int branchSoftCap = 4;
-
-    @MinNumber(0)
-    @MaxNumber(1)
-    @Desc("The multiplicative survival factor for each child beyond branchSoftCap. Recursive generations remain unbounded by depth.")
-    private double branchChildShrinkFactor = 0.35D;
-
     @MinNumber(0)
     @MaxNumber(16)
     @Desc("The contribution of natural terrain height to downstream routing cost.")

core/src/main/java/art/arcane/iris/engine/object/IrisRiverWorm.java

@@ -0,0 +1,133 @@
+package art.arcane.iris.engine.object;
+
+import art.arcane.iris.engine.object.annotations.ArrayType;
+import art.arcane.iris.engine.object.annotations.Desc;
+import art.arcane.iris.engine.object.annotations.MaxNumber;
+import art.arcane.iris.engine.object.annotations.MinNumber;
+import art.arcane.iris.engine.object.annotations.Required;
+import art.arcane.volmlib.util.collection.KList;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import lombok.experimental.Accessors;
+
+@Accessors(chain = true)
+@NoArgsConstructor
+@Desc("One weighted Perlin-worm river shape and its channel proportions.")
+@Data
+public class IrisRiverWorm {
+    @Required
+    @Desc("Unique lowercase identifier for this root or child style.")
+    private String id = "river";
+
+    @Desc("Stable salt for this Perlin field pair.")
+    private long seed = 1L;
+
+    @MinNumber(0.000001)
+    @MaxNumber(1000000)
+    @Desc("Relative probability when selecting this root family or one child transition.")
+    private double weight = 1D;
+
+    @MinNumber(8)
+    @MaxNumber(16384)
+    @Desc("Primary gradient-Perlin wavelength in blocks.")
+    private double wavelength = 1024D;
+
+    @MinNumber(8)
+    @MaxNumber(16384)
+    @Desc("Secondary gradient-Perlin wavelength in blocks.")
+    private double detailWavelength = 256D;
+
+    @MinNumber(0)
+    @MaxNumber(1)
+    @Desc("Primary heading deviation as a fraction of 180 degrees.")
+    private double tortuosity = 0.5D;
+
+    @MinNumber(0)
+    @MaxNumber(1)
+    @Desc("Secondary heading deviation as a fraction of 180 degrees.")
+    private double detailTortuosity = 0.15D;
+
+    @MinNumber(0)
+    @MaxNumber(1024)
+    @Desc("Maximum endpoint-bridged displacement from the reach chord in blocks.")
+    private double maxOffset = 320D;
+
+    @MinNumber(1)
+    @MaxNumber(64)
+    @Desc("Number of deterministic Perlin-worm steps used to resolve the reach.")
+    private int segments = 48;
+
+    @MinNumber(0.125)
+    @MaxNumber(8)
+    @Desc("Channel-width multiplier for reaches selecting this worm.")
+    private double widthMultiplier = 1D;
+
+    @MinNumber(0.125)
+    @MaxNumber(8)
+    @Desc("Bank-width multiplier for reaches selecting this worm.")
+    private double bankMultiplier = 1D;
+
+    @MinNumber(0.125)
+    @MaxNumber(8)
+    @Desc("Depth multiplier for reaches selecting this worm.")
+    private double depthMultiplier = 1D;
+
+    @MinNumber(32)
+    @MaxNumber(16384)
+    @Desc("Primary world-space wavelength controlling longitudinal body swelling and pinching.")
+    private double bodyWavelength = 512D;
+
+    @MinNumber(32)
+    @MaxNumber(16384)
+    @Desc("Detail wavelength adding smaller changes to the longitudinal body profile.")
+    private double bodyDetailWavelength = 128D;
+
+    @MinNumber(0)
+    @MaxNumber(0.875)
+    @Desc("Maximum proportional channel-width variation along this style's body.")
+    private double widthVariation = 0D;
+
+    @MinNumber(0)
+    @MaxNumber(0.875)
+    @Desc("Maximum proportional bank or basin-width variation along this style's body.")
+    private double bankVariation = 0D;
+
+    @MinNumber(0)
+    @MaxNumber(0.875)
+    @Desc("Maximum proportional bed-depth variation along this style's body.")
+    private double depthVariation = 0D;
+
+    @MinNumber(0)
+    @MaxNumber(0.875)
+    @Desc("Maximum downward variation of tunnel roof clearance without exceeding the authored cave headroom.")
+    private double roofVariation = 0D;
+
+    @MinNumber(1)
+    @MaxNumber(8)
+    @Desc("Number of upstream children admitted before additional siblings decay probabilistically.")
+    private int branchCap = 4;
+
+    @MinNumber(0)
+    @MaxNumber(1)
+    @Desc("Multiplicative survival probability for every sibling beyond branchCap.")
+    private double branchDecay = 0.35D;
+
+    @MinNumber(0)
+    @MaxNumber(8)
+    @Desc("Multiplier applied to the dimension confluence attraction for this style.")
+    private double confluenceMultiplier = 1D;
+
+    @MinNumber(0)
+    @MaxNumber(1)
+    @Desc("Chance that an upstream continuation mutates from this style into one weighted child.")
+    private double childChance = 0D;
+
+    @MinNumber(0)
+    @MaxNumber(1)
+    @Desc("Additional child-mutation chance for each sibling slot beyond the primary branch.")
+    private double branchChildChance = 0D;
+
+    @ArrayType(type = IrisRiverWorm.class)
+    @Desc("Weighted descendant styles inherited by the complete upstream lineage after mutation.")
+    private KList<IrisRiverWorm> children = new KList<IrisRiverWorm>();
+}

core/src/main/java/art/arcane/iris/engine/river/RiverBodyProfile.java

@@ -0,0 +1,182 @@
+package art.arcane.iris.engine.river;
+
+import java.util.Arrays;
+
+public final class RiverBodyProfile {
+    private final double[] positions;
+    private final double[] widths;
+    private final double[] bankWidths;
+    private final double[] depths;
+    private final double[] roofScales;
+    private final double maximumWidth;
+    private final double maximumBankWidth;
+    private final double maximumDepth;
+
+    public RiverBodyProfile(
+            double[] positions,
+            double[] widths,
+            double[] bankWidths,
+            double[] depths,
+            double[] roofScales
+    ) {
+        if (positions == null || widths == null || bankWidths == null || depths == null || roofScales == null
+                || positions.length < 2
+                || positions.length != widths.length
+                || positions.length != bankWidths.length
+                || positions.length != depths.length
+                || positions.length != roofScales.length) {
+            throw new IllegalArgumentException("River body profiles require matching dimension samples");
+        }
+        this.positions = positions.clone();
+        this.widths = widths.clone();
+        this.bankWidths = bankWidths.clone();
+        this.depths = depths.clone();
+        this.roofScales = roofScales.clone();
+        double resolvedMaximumWidth = 0D;
+        double resolvedMaximumBankWidth = 0D;
+        double resolvedMaximumDepth = 0D;
+        for (int index = 0; index < this.positions.length; index++) {
+            double position = this.positions[index];
+            if (!Double.isFinite(position) || position < 0D || position > 1D
+                    || index > 0 && position <= this.positions[index - 1]) {
+                throw new IllegalArgumentException("River body profile positions must increase from zero to one");
+            }
+            requirePositive(this.widths[index], "width");
+            requireNonNegative(this.bankWidths[index], "bank width");
+            requirePositive(this.depths[index], "depth");
+            requireUnitScale(this.roofScales[index], "roof scale");
+            resolvedMaximumWidth = StrictMath.max(resolvedMaximumWidth, this.widths[index]);
+            resolvedMaximumBankWidth = StrictMath.max(resolvedMaximumBankWidth, this.bankWidths[index]);
+            resolvedMaximumDepth = StrictMath.max(resolvedMaximumDepth, this.depths[index]);
+        }
+        if (this.positions[0] != 0D || this.positions[this.positions.length - 1] != 1D) {
+            throw new IllegalArgumentException("River body profile positions must include zero and one");
+        }
+        maximumWidth = resolvedMaximumWidth;
+        maximumBankWidth = resolvedMaximumBankWidth;
+        maximumDepth = resolvedMaximumDepth;
+    }
+
+    public static RiverBodyProfile constant(double width, double bankWidth, double depth) {
+        return new RiverBodyProfile(
+                new double[]{0D, 1D},
+                new double[]{width, width},
+                new double[]{bankWidth, bankWidth},
+                new double[]{depth, depth},
+                new double[]{1D, 1D}
+        );
+    }
+
+    public double width(double alongReach) {
+        return sample(widths, alongReach);
+    }
+
+    public double bankWidth(double alongReach) {
+        return sample(bankWidths, alongReach);
+    }
+
+    public double depth(double alongReach) {
+        return sample(depths, alongReach);
+    }
+
+    public double roofScale(double alongReach) {
+        return sample(roofScales, alongReach);
+    }
+
+    public double maximumWidth() {
+        return maximumWidth;
+    }
+
+    public double maximumBankWidth() {
+        return maximumBankWidth;
+    }
+
+    public double maximumDepth() {
+        return maximumDepth;
+    }
+
+    public int size() {
+        return positions.length;
+    }
+
+    public double position(int index) {
+        return positions[index];
+    }
+
+    public double widthAtIndex(int index) {
+        return widths[index];
+    }
+
+    public double bankWidthAtIndex(int index) {
+        return bankWidths[index];
+    }
+
+    public double depthAtIndex(int index) {
+        return depths[index];
+    }
+
+    public double roofScaleAtIndex(int index) {
+        return roofScales[index];
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object) {
+            return true;
+        }
+        if (!(object instanceof RiverBodyProfile profile)) {
+            return false;
+        }
+        return Arrays.equals(positions, profile.positions)
+                && Arrays.equals(widths, profile.widths)
+                && Arrays.equals(bankWidths, profile.bankWidths)
+                && Arrays.equals(depths, profile.depths)
+                && Arrays.equals(roofScales, profile.roofScales);
+    }
+
+    @Override
+    public int hashCode() {
+        int hash = Arrays.hashCode(positions);
+        hash = 31 * hash + Arrays.hashCode(widths);
+        hash = 31 * hash + Arrays.hashCode(bankWidths);
+        hash = 31 * hash + Arrays.hashCode(depths);
+        return 31 * hash + Arrays.hashCode(roofScales);
+    }
+
+    private double sample(double[] values, double alongReach) {
+        double position = StrictMath.max(0D, StrictMath.min(1D, alongReach));
+        int index = Arrays.binarySearch(positions, position);
+        if (index >= 0) {
+            return values[index];
+        }
+        int upper = -index - 1;
+        if (upper <= 0) {
+            return values[0];
+        }
+        if (upper >= positions.length) {
+            return values[values.length - 1];
+        }
+        int lower = upper - 1;
+        double range = positions[upper] - positions[lower];
+        double interpolation = range <= 0D ? 0D : (position - positions[lower]) / range;
+        return values[lower] + (values[upper] - values[lower]) * interpolation;
+    }
+
+    private static void requirePositive(double value, String name) {
+        if (!Double.isFinite(value) || value <= 0D) {
+            throw new IllegalArgumentException("River body profile " + name + " must be finite and positive");
+        }
+    }
+
+    private static void requireNonNegative(double value, String name) {
+        if (!Double.isFinite(value) || value < 0D) {
+            throw new IllegalArgumentException("River body profile " + name + " must be finite and non-negative");
+        }
+    }
+
+    private static void requireUnitScale(double value, String name) {
+        if (!Double.isFinite(value) || value <= 0D || value > 1D) {
+            throw new IllegalArgumentException("River body profile " + name + " must be greater than zero and at most one");
+        }
+    }
+}

core/src/main/java/art/arcane/iris/engine/river/RiverMeanderContext.java

@@ -1,18 +0,0 @@
-package art.arcane.iris.engine.river;
-
-import java.util.Objects;
-
-public record RiverMeanderContext(
-        RiverEdgeId reachId,
-        double normalizedPosition,
-        double x,
-        double z
-) {
-    public RiverMeanderContext {
-        Objects.requireNonNull(reachId);
-        if (!Double.isFinite(normalizedPosition) || normalizedPosition < 0.0 || normalizedPosition > 1.0
-                || !Double.isFinite(x) || !Double.isFinite(z)) {
-            throw new IllegalArgumentException("River meander context must be finite and normalized");
-        }
-    }
-}

core/src/main/java/art/arcane/iris/engine/river/RiverNetwork.java

@@ -21,21 +21,25 @@ public final class RiverNetwork {
     private static final long SOURCE_FLOOR_SALT = 0xD6E8FEB86659FD93L;
     private static final long REACH_SALT = 0x9B05688C2B3E6C1FL;
     private static final long DRY_SALT = 0x1F83D9ABFB41BD6BL;
-    private static final long MEANDER_SALT = 0x5BE0CD19137E2179L;
-    private static final long MEANDER_PERSONALITY_SALT = 0x243F6A8885A308D3L;
-    private static final long MEANDER_AMPLITUDE_SALT = 0x13198A2E03707344L;
-    private static final long MEANDER_PHASE_SALT = 0xD1310BA698DFB5ACL;
-    private static final long MEANDER_SKEW_SALT = 0x2FFD72DBD01ADFB7L;
-    private static final long MEANDER_CYCLE_SALT = 0x452821E638D01377L;
-    private static final long MEANDER_FEATURE_A_SALT = 0xBE5466CF34E90C6CL;
-    private static final long MEANDER_FEATURE_B_SALT = 0xC0AC29B7C97C50DDL;
+    private static final long WORM_FAMILY_SALT = 0x5BE0CD19137E2179L;
+    private static final long WORM_CHILD_GATE_SALT = 0x452821E638D01377L;
+    private static final long WORM_CHILD_SELECTION_SALT = 0xBE5466CF34E90C6CL;
+    private static final long WORM_PRIMARY_SALT = 0x243F6A8885A308D3L;
+    private static final long WORM_DETAIL_SALT = 0x13198A2E03707344L;
+    private static final long BODY_WIDTH_PRIMARY_SALT = 0xA4093822299F31D0L;
+    private static final long BODY_WIDTH_DETAIL_SALT = 0x082EFA98EC4E6C89L;
+    private static final long BODY_BANK_PRIMARY_SALT = 0x452821E638D01377L;
+    private static final long BODY_BANK_DETAIL_SALT = 0xBE5466CF34E90C6CL;
+    private static final long BODY_DEPTH_PRIMARY_SALT = 0xC0AC29B7C97C50DDL;
+    private static final long BODY_DEPTH_DETAIL_SALT = 0x3F84D5B5B5470917L;
+    private static final long BODY_ROOF_PRIMARY_SALT = 0xD1310BA698DFB5ACL;
+    private static final long BODY_ROOF_DETAIL_SALT = 0x2FFD72DBD01ADFB7L;
     private static final long CONFLUENCE_SALT = 0x9E3779B97F4A7C15L;
     private static final long BRANCH_SLOT_SALT = 0x94D049BB133111EBL;
     private static final long BRANCH_GATE_SALT = 0x2545F4914F6CDD1DL;
-    private static final int MEANDER_NOISE_SAMPLES = 12;
-    private static final int WIDTH_PROFILE_SAMPLES = 12;
-    private static final double TWO_PI = StrictMath.PI * 2D;
-    private static final MeanderPersonality[] MEANDER_PERSONALITIES = MeanderPersonality.values();
+    private static final int MINIMUM_BODY_PROFILE_SAMPLES = 12;
+    private static final int MAXIMUM_BODY_PROFILE_SAMPLES = 32;
+    private static final double PERLIN_NORMALIZATION = 1.4142135623730951D;
 
     private final RiverNetworkOptions options;
 
@@ -208,7 +212,7 @@ public final class RiverNetwork {
         double routingScore = naturalHeight * options.terrainHeightWeight()
                 + routingNoise * options.routingNoiseWeight()
                 + finiteOrZero(terrainSample.routingCost());
-        double drainageDistance = drainageDistance(id);
+        double drainageDistance = drainageBasin(id).distance();
         double hydraulicHeight = ocean
                 ? options.hydraulicBaseHeight()
                 : options.hydraulicBaseHeight()
@@ -228,6 +232,10 @@ public final class RiverNetwork {
     }
 
     private double drainageDistance(RiverNodeId id) {
+        return drainageBasin(id).distance();
+    }
+
+    private DrainageBasin drainageBasin(RiverNodeId id) {
         int basinCells = options.routingBasinCells();
         double nodeX = id.cellX() + 0.5D;
         double nodeZ = id.cellZ() + 0.5D;
@@ -245,19 +253,21 @@ public final class RiverNetwork {
         long basinZ = (long) StrictMath.floor(nodeZ / basinCells);
         double jitterRadius = basinCells * 0.45D;
         double nearestDistance = Double.MAX_VALUE;
+        DrainageBasinId nearestId = null;
         for (long candidateX = basinX - 1L; candidateX <= basinX + 1L; candidateX++) {
             for (long candidateZ = basinZ - 1L; candidateZ <= basinZ + 1L; candidateZ++) {
                 double siteX = (candidateX + 0.5D) * basinCells
                         + centered(hash(candidateX, candidateZ, BASIN_X_SALT)) * jitterRadius;
                 double siteZ = (candidateZ + 0.5D) * basinCells
                         + centered(hash(candidateX, candidateZ, BASIN_Z_SALT)) * jitterRadius;
-                nearestDistance = StrictMath.min(
-                        nearestDistance,
-                        StrictMath.hypot(nodeX - siteX, nodeZ - siteZ)
-                );
+                double distance = StrictMath.hypot(nodeX - siteX, nodeZ - siteZ);
+                if (distance < nearestDistance) {
+                    nearestDistance = distance;
+                    nearestId = new DrainageBasinId(candidateX, candidateZ);
                 }
             }
-        return nearestDistance;
+        }
+        return new DrainageBasin(nearestId, nearestDistance);
     }
 
     private double smoothCellNoise(double x, double z, int scale, long salt) {
@@ -305,7 +315,8 @@ public final class RiverNetwork {
             if (compareRank(neighbor, node) >= 0) {
                 continue;
             }
-            if (!branchPermitted(node, neighbor, resolver)) {
+            RiverWorm worm = resolver.worm(node, neighbor);
+            if (!branchPermitted(node, neighbor, resolver, worm)) {
                 continue;
             }
             RiverRoutingContext context = resolver.routingContext(node, neighbor);
@@ -313,7 +324,8 @@ public final class RiverNetwork {
             double oceanAttraction = neighbor.ocean() ? options.oceanAttraction() : 0.0;
             double flowAlignmentCost = flowAlignmentCost(node, neighbor, resolver);
             double confluenceAttraction = unit(hash(neighbor.id(), CONFLUENCE_SALT))
-                    * options.confluenceWeight();
+                    * options.confluenceWeight()
+                    * worm.confluenceMultiplier();
             ranked.add(new RankedCandidate(
                     neighbor,
                     neighbor.routingScore() + routingCost + flowAlignmentCost
@@ -331,15 +343,20 @@ public final class RiverNetwork {
         return List.copyOf(candidates);
     }
 
-    private boolean branchPermitted(RiverNode child, RiverNode parent, NodeResolver resolver) {
+    private boolean branchPermitted(
+            RiverNode child,
+            RiverNode parent,
+            NodeResolver resolver,
+            RiverWorm worm
+    ) {
         RiverEdgeId childEdge = RiverEdgeId.of(child.id(), parent.id());
         int childSlot = resolver.branchSlot(parent, child);
-        if (childSlot < options.branchSoftCap()) {
+        if (childSlot < worm.branchCap()) {
             return true;
         }
         double survivalChance = 1D;
-        for (int overflow = options.branchSoftCap(); overflow <= childSlot; overflow++) {
-            survivalChance *= options.branchChildShrinkFactor();
+        for (int overflow = worm.branchCap(); overflow <= childSlot; overflow++) {
+            survivalChance *= worm.branchDecay();
         }
         return gate(hash(childEdge, BRANCH_GATE_SALT), survivalChance);
     }
@@ -427,6 +444,7 @@ public final class RiverNetwork {
                         from,
                         to,
                         resolver.routingContext(from, to),
+                        resolver.worm(from, to),
                         resolver.terrain
                 );
                 accumulators.put(edgeId, accumulator);
@@ -451,61 +469,65 @@ public final class RiverNetwork {
     }
 
     private RiverPolyline createPolyline(
-            RiverEdgeId id,
             RiverNode from,
             RiverNode to,
-            NodeResolver resolver
+            RiverWorm worm
     ) {
-        int pointCount = options.meanderSubdivisions() + 1;
-        double[] baseX = new double[pointCount];
-        double[] baseZ = new double[pointCount];
+        int pointCount = worm.segments() + 1;
+        double[] rawX = new double[pointCount];
+        double[] rawZ = new double[pointCount];
         double deltaX = to.x() - from.x();
         double deltaZ = to.z() - from.z();
         double length = StrictMath.hypot(deltaX, deltaZ);
-        double maximumOffset = StrictMath.min(options.meanderStrength(), length * 0.35);
-        double directionX = length == 0D ? 1D : deltaX / length;
-        double directionZ = length == 0D ? 0D : deltaZ / length;
-        FlowTangent fromTangent = flowTangent(from, directionX, directionZ, resolver);
-        FlowTangent toTangent = flowTangent(to, directionX, directionZ, resolver);
-        for (int point = 0; point < pointCount; point++) {
-            double t = (double) point / (pointCount - 1);
-            double tSquared = t * t;
-            double tCubed = tSquared * t;
-            double fromWeight = 2D * tCubed - 3D * tSquared + 1D;
-            double fromTangentWeight = tCubed - 2D * tSquared + t;
-            double toWeight = -2D * tCubed + 3D * tSquared;
-            double toTangentWeight = tCubed - tSquared;
-            double curvedX = fromWeight * from.x()
-                    + fromTangentWeight * fromTangent.x() * maximumOffset
-                    + toWeight * to.x()
-                    + toTangentWeight * toTangent.x() * maximumOffset;
-            double curvedZ = fromWeight * from.z()
-                    + fromTangentWeight * fromTangent.z() * maximumOffset
-                    + toWeight * to.z()
-                    + toTangentWeight * toTangent.z() * maximumOffset;
-            baseX[point] = curvedX;
-            baseZ[point] = curvedZ;
+        rawX[0] = from.x();
+        rawZ[0] = from.z();
+        if (length <= 0D) {
+            return new RiverPolyline(rawX, rawZ);
         }
-        if (maximumOffset <= 0D) {
-            return new RiverPolyline(baseX, baseZ);
+        double baseHeading = StrictMath.atan2(deltaZ, deltaX);
+        double stepLength = length / worm.segments();
+        for (int point = 1; point < pointCount; point++) {
+            double x = rawX[point - 1];
+            double z = rawZ[point - 1];
+            double primary = perlin(x, z, worm.wavelength(), worm.seed() ^ WORM_PRIMARY_SALT);
+            double detail = perlin(x, z, worm.detailWavelength(), worm.seed() ^ WORM_DETAIL_SALT);
+            double heading = baseHeading + StrictMath.PI * (
+                    primary * worm.tortuosity()
+                            + detail * worm.detailTortuosity()
+            );
+            rawX[point] = x + StrictMath.cos(heading) * stepLength;
+            rawZ[point] = z + StrictMath.sin(heading) * stepLength;
         }
-        MeanderProfile profile = meanderProfile(id);
-        double[] meanderNoise = meanderNoise(id, baseX, baseZ, resolver);
-        double[] meanderSignal = meanderSignal(id, profile, meanderNoise);
         double[] x = new double[pointCount];
         double[] z = new double[pointCount];
+        double rawDeltaX = rawX[pointCount - 1] - from.x();
+        double rawDeltaZ = rawZ[pointCount - 1] - from.z();
+        double maximumDisplacement = 0D;
         for (int point = 0; point < pointCount; point++) {
             double t = (double) point / (pointCount - 1);
             double tSquared = t * t;
             double envelope = 16D * tSquared * (1D - t) * (1D - t);
             double straightX = from.x() + deltaX * t;
             double straightZ = from.z() + deltaZ * t;
-            double baseDisplacement = StrictMath.hypot(baseX[point] - straightX, baseZ[point] - straightZ);
-            double availableOffset = StrictMath.max(0D, maximumOffset - baseDisplacement);
-            double offset = availableOffset * 0.92D * envelope * meanderSignal[point];
-            FlowTangent normal = localNormal(baseX, baseZ, point);
-            x[point] = baseX[point] + normal.x() * offset;
-            z[point] = baseZ[point] + normal.z() * offset;
+            double rawBridgeX = rawX[point] - (from.x() + rawDeltaX * t);
+            double rawBridgeZ = rawZ[point] - (from.z() + rawDeltaZ * t);
+            x[point] = straightX + rawBridgeX * envelope;
+            z[point] = straightZ + rawBridgeZ * envelope;
+            maximumDisplacement = StrictMath.max(
+                    maximumDisplacement,
+                    StrictMath.hypot(x[point] - straightX, z[point] - straightZ)
+            );
+        }
+        double maximumOffset = StrictMath.min(worm.maxOffset(), length * 0.35D);
+        if (maximumDisplacement > maximumOffset && maximumDisplacement > 0D) {
+            double scale = maximumOffset / maximumDisplacement;
+            for (int point = 1; point < pointCount - 1; point++) {
+                double t = (double) point / (pointCount - 1);
+                double straightX = from.x() + deltaX * t;
+                double straightZ = from.z() + deltaZ * t;
+                x[point] = straightX + (x[point] - straightX) * scale;
+                z[point] = straightZ + (z[point] - straightZ) * scale;
+            }
         }
         x[0] = from.x();
         z[0] = from.z();
@@ -514,222 +536,141 @@ public final class RiverNetwork {
         return new RiverPolyline(x, z);
     }
 
-    private double[] meanderNoise(
-            RiverEdgeId id,
-            double[] baseX,
-            double[] baseZ,
-            NodeResolver resolver
+    private RiverWorm rootWormFor(RiverNodeId rootId) {
+        return selectWeighted(options.worms(), hash(rootId, WORM_FAMILY_SALT));
+    }
+
+    private RiverWorm childWormFor(
+            RiverWorm parent,
+            RiverNodeId parentId,
+            RiverNodeId childId,
+            int branchSlot
     ) {
-        int sampleCount = StrictMath.min(MEANDER_NOISE_SAMPLES, baseX.length);
-        double[] knots = new double[sampleCount];
-        for (int sample = 0; sample < sampleCount; sample++) {
-            double t = (double) sample / (sampleCount - 1);
-            double position = t * (baseX.length - 1);
-            int lower = (int) StrictMath.floor(position);
-            int upper = StrictMath.min(baseX.length - 1, lower + 1);
-            double interpolation = position - lower;
-            double curvedX = baseX[lower] + (baseX[upper] - baseX[lower]) * interpolation;
-            double curvedZ = baseZ[lower] + (baseZ[upper] - baseZ[lower]) * interpolation;
-            RiverMeanderContext context = new RiverMeanderContext(id, t, curvedX, curvedZ);
-            double configuredNoise = resolver.terrain.meanderNoise(context);
-            knots[sample] = Double.isFinite(configuredNoise)
-                    ? StrictMath.max(-1D, StrictMath.min(1D, configuredNoise))
-                    : smoothEdgeNoise(id, t * 3D);
+        if (parent.children().isEmpty()) {
+            return parent;
         }
-        double[] noise = new double[baseX.length];
-        for (int point = 0; point < noise.length; point++) {
-            double t = (double) point / (noise.length - 1);
-            double position = t * (sampleCount - 1);
-            int lower = (int) StrictMath.floor(position);
-            int upper = StrictMath.min(sampleCount - 1, lower + 1);
-            double interpolation = smoothStep(position - lower);
-            noise[point] = knots[lower] + (knots[upper] - knots[lower]) * interpolation;
+        double chance = StrictMath.min(
+                1D,
+                parent.childChance()
+                        + StrictMath.min(7, branchSlot) * parent.branchChildChance()
+        );
+        RiverEdgeId edgeId = RiverEdgeId.of(childId, parentId);
+        if (!gate(hash(edgeId, WORM_CHILD_GATE_SALT), chance)) {
+            return parent;
         }
-        return noise;
+        return selectWeighted(parent.children(), hash(edgeId, WORM_CHILD_SELECTION_SALT));
     }
 
-    private MeanderProfile meanderProfile(RiverEdgeId id) {
-        int personalityIndex = (int) StrictMath.floor(
-                unit(hash(id, MEANDER_PERSONALITY_SALT)) * MEANDER_PERSONALITIES.length
+    private RiverWorm selectWeighted(List<RiverWorm> worms, long selectionHash) {
+        double totalWeight = 0D;
+        for (RiverWorm worm : worms) {
+            totalWeight += worm.weight();
+        }
+        double selection = unit(selectionHash) * totalWeight;
+        double cumulative = 0D;
+        for (RiverWorm worm : worms) {
+            cumulative += worm.weight();
+            if (selection < cumulative) {
+                return worm;
+            }
+        }
+        return worms.get(worms.size() - 1);
+    }
+
+    private double perlin(double x, double z, double wavelength, long salt) {
+        double scaledX = x / wavelength;
+        double scaledZ = z / wavelength;
+        long minimumX = (long) StrictMath.floor(scaledX);
+        long minimumZ = (long) StrictMath.floor(scaledZ);
+        double fractionX = scaledX - minimumX;
+        double fractionZ = scaledZ - minimumZ;
+        double fadeX = perlinFade(fractionX);
+        double fadeZ = perlinFade(fractionZ);
+        double northwest = perlinGradient(minimumX, minimumZ, fractionX, fractionZ, salt);
+        double northeast = perlinGradient(minimumX + 1L, minimumZ, fractionX - 1D, fractionZ, salt);
+        double southwest = perlinGradient(minimumX, minimumZ + 1L, fractionX, fractionZ - 1D, salt);
+        double southeast = perlinGradient(
+                minimumX + 1L,
+                minimumZ + 1L,
+                fractionX - 1D,
+                fractionZ - 1D,
+                salt
         );
-        MeanderPersonality personality = MEANDER_PERSONALITIES[
-                StrictMath.min(MEANDER_PERSONALITIES.length - 1, personalityIndex)
-        ];
-        double amplitudeRoll = unit(hash(id, MEANDER_AMPLITUDE_SALT));
-        double amplitude = personality == MeanderPersonality.QUIET
-                ? 0.16D + amplitudeRoll * 0.24D
-                : 0.48D + amplitudeRoll * 0.52D;
-        double maximumCycles = StrictMath.max(1D, StrictMath.min(8D, options.meanderSubdivisions() / 5D));
-        double cycleRoll = unit(hash(id, MEANDER_CYCLE_SALT));
-        double cycles = switch (personality) {
-            case SWEEP, HOOK, QUIET -> 0.45D + cycleRoll * 0.65D;
-            case S_CURVE -> 0.75D + cycleRoll * StrictMath.min(1.25D, maximumCycles);
-            case OXBOW -> 1D + cycleRoll * StrictMath.min(1.5D, maximumCycles);
-            case COIL -> StrictMath.min(maximumCycles, 2.25D + cycleRoll * 4.75D);
-            case WANDER -> 0.65D + cycleRoll * StrictMath.min(2.35D, maximumCycles);
-            case CHIRP -> StrictMath.min(maximumCycles, 1.5D + cycleRoll * 5.5D);
-        };
-        double handedness = (hash(id, MEANDER_SALT) & 1L) == 0L ? -1D : 1D;
-        return new MeanderProfile(
-                personality,
-                amplitude,
-                handedness,
-                unit(hash(id, MEANDER_PHASE_SALT)) * TWO_PI,
-                centered(hash(id, MEANDER_SKEW_SALT)) * 0.72D,
-                cycles,
-                unit(hash(id, MEANDER_FEATURE_A_SALT)),
-                unit(hash(id, MEANDER_FEATURE_B_SALT))
+        double north = northwest + (northeast - northwest) * fadeX;
+        double south = southwest + (southeast - southwest) * fadeX;
+        return StrictMath.max(
+                -1D,
+                StrictMath.min(1D, (north + (south - north) * fadeZ) * PERLIN_NORMALIZATION)
         );
     }
 
-    private double[] meanderSignal(RiverEdgeId id, MeanderProfile profile, double[] noise) {
-        int subdivisions = noise.length - 1;
-        for (int point = 0; point < noise.length; point++) {
-            double t = (double) point / subdivisions;
-            noise[point] = noise[point] * 0.78D + smoothEdgeNoise(id, t * 3.5D) * 0.22D;
-        }
-        smoothSignal(noise);
-        double detailCycles = StrictMath.max(0.5D, profile.cycles() + profile.featureB() * 1.5D);
-        double baseStep = TWO_PI * detailCycles / subdivisions;
-        double phase = profile.phase() + profile.featureA() * StrictMath.PI;
-        double[] signal = new double[noise.length];
-        for (int point = 0; point < noise.length; point++) {
-            double t = (double) point / subdivisions;
-            if (point > 0) {
-                double frequencyNoise = (noise[point - 1] + noise[point]) * 0.25D + 0.5D;
-                phase += baseStep * (0.45D + frequencyNoise * 1.1D);
-            }
-            double warpedT = warpMeanderPosition(t, profile.skew());
-            double macro = personalitySignal(profile, warpedT, noise[point]);
-            double detailWeight = detailWeight(profile.personality());
-            double detail = detailWeight <= 0D
-                    ? 0D
-                    : StrictMath.sin(phase) * (0.65D + StrictMath.abs(noise[point]) * 0.35D);
-            double noiseWeight = noiseWeight(profile.personality());
-            double macroWeight = 1D - detailWeight - noiseWeight;
-            signal[point] = clampSigned(profile.amplitude()
-                    * (macro * macroWeight + detail * detailWeight + noise[point] * noiseWeight));
-        }
-        smoothSignal(signal);
-        return signal;
-    }
-
-    private double personalitySignal(MeanderProfile profile, double t, double noise) {
-        double handedness = profile.handedness();
-        return switch (profile.personality()) {
-            case SWEEP -> handedness * (0.68D + StrictMath.sin(StrictMath.PI * t) * 0.32D);
-            case HOOK -> handedness * (0.12D + smoothStep(
-                    profile.featureA() < 0.5D ? t : 1D - t
-            ) * 0.88D);
-            case S_CURVE -> handedness * StrictMath.sin(
-                    TWO_PI * profile.cycles() * t + profile.phase()
-            );
-            case COIL -> StrictMath.sin(TWO_PI * profile.cycles() * t + profile.phase())
-                    * (0.62D + StrictMath.sin(StrictMath.PI * t) * 0.38D);
-            case WANDER -> clampSigned(
-                    noise * 0.82D
-                            + StrictMath.sin(TWO_PI * profile.cycles() * t + profile.phase()) * 0.38D
-                            + handedness * 0.12D
-            );
-            case OXBOW -> handedness * clampSigned(
-                    compactLobe(t, 0.18D + profile.featureA() * 0.2D, 0.24D + profile.featureB() * 0.12D)
-                            - compactLobe(t, 0.62D + profile.featureB() * 0.2D, 0.22D + profile.featureA() * 0.14D)
-                                    * (0.55D + profile.featureA() * 0.45D)
-            );
-            case CHIRP -> StrictMath.sin(
-                    profile.phase() + TWO_PI * (0.45D * t + profile.cycles() * t * t)
-            );
-            case QUIET -> handedness * (0.72D + noise * 0.28D);
+    private double perlinGradient(long latticeX, long latticeZ, double x, double z, long salt) {
+        return switch ((int) (hash(latticeX, latticeZ, salt) & 7L)) {
+            case 0 -> x;
+            case 1 -> -x;
+            case 2 -> z;
+            case 3 -> -z;
+            case 4 -> (x + z) / PERLIN_NORMALIZATION;
+            case 5 -> (-x + z) / PERLIN_NORMALIZATION;
+            case 6 -> (x - z) / PERLIN_NORMALIZATION;
+            default -> (-x - z) / PERLIN_NORMALIZATION;
         };
     }
 
-    private double detailWeight(MeanderPersonality personality) {
-        return switch (personality) {
-            case SWEEP, HOOK, OXBOW, QUIET -> 0D;
-            case S_CURVE -> 0.12D;
-            case COIL, WANDER -> 0.08D;
-            case CHIRP -> 0.1D;
-        };
+    private double perlinFade(double value) {
+        double squared = value * value;
+        double cubed = squared * value;
+        return cubed * (value * (value * 6D - 15D) + 10D);
     }
 
-    private double noiseWeight(MeanderPersonality personality) {
-        return switch (personality) {
-            case SWEEP, S_CURVE, COIL, OXBOW, CHIRP -> 0.08D;
-            case HOOK -> 0.1D;
-            case WANDER -> 0.34D;
-            case QUIET -> 0.14D;
-        };
-    }
-
-    private double warpMeanderPosition(double t, double skew) {
-        return t + skew * t * (1D - t);
-    }
-
-    private double compactLobe(double t, double center, double radius) {
-        double distance = StrictMath.abs(t - center) / radius;
-        if (distance >= 1D) {
-            return 0D;
-        }
-        return smoothStep(1D - distance);
-    }
-
-    private double smoothStep(double value) {
-        double clamped = StrictMath.max(0D, StrictMath.min(1D, value));
-        return clamped * clamped * (3D - 2D * clamped);
-    }
-
-    private void smoothSignal(double[] signal) {
-        if (signal.length < 3) {
-            return;
-        }
-        double previousRaw = signal[0];
-        double currentRaw = signal[1];
-        for (int point = 1; point < signal.length - 1; point++) {
-            double nextRaw = signal[point + 1];
-            signal[point] = (previousRaw + currentRaw * 2D + nextRaw) * 0.25D;
-            previousRaw = currentRaw;
-            currentRaw = nextRaw;
-        }
-    }
-
-    private double clampSigned(double value) {
-        return StrictMath.max(-1D, StrictMath.min(1D, value));
-    }
-
-    private FlowTangent localNormal(double[] x, double[] z, int point) {
-        int previous = StrictMath.max(0, point - 1);
-        int next = StrictMath.min(x.length - 1, point + 1);
-        double tangentX = x[next] - x[previous];
-        double tangentZ = z[next] - z[previous];
-        double tangentLength = StrictMath.hypot(tangentX, tangentZ);
-        if (tangentLength <= 0.0000001D) {
-            return new FlowTangent(0D, 0D);
-        }
-        return new FlowTangent(-tangentZ / tangentLength, tangentX / tangentLength);
-    }
-
-    private FlowTangent flowTangent(
-            RiverNode node,
-            double fallbackX,
-            double fallbackZ,
-            NodeResolver resolver
+    private double bodyMultiplier(
+            ReachPosition position,
+            RiverWorm worm,
+            long primarySalt,
+            long detailSalt,
+            double variation
     ) {
-        FlowTangent preferred = resolver.flowTangent(node);
-        double tangentX = preferred.x();
-        double tangentZ = preferred.z();
-        if (tangentX == 0D && tangentZ == 0D) {
-            return new FlowTangent(fallbackX, fallbackZ);
+        if (variation <= 0D) {
+            return 1D;
         }
-        double alignment = tangentX * fallbackX + tangentZ * fallbackZ;
-        if (alignment < 0D) {
-            tangentX = -tangentX;
-            tangentZ = -tangentZ;
-            alignment = -alignment;
+        return StrictMath.max(
+                0.125D,
+                1D + bodyField(position, worm, primarySalt, detailSalt) * variation
+        );
     }
-        if (alignment < 0.15D) {
-            return new FlowTangent(fallbackX, fallbackZ);
+
+    private double roofScale(ReachPosition position, RiverWorm worm) {
+        if (worm.roofVariation() <= 0D) {
+            return 1D;
         }
-        return new FlowTangent(tangentX, tangentZ);
+        double normalized = bodyField(
+                position,
+                worm,
+                BODY_ROOF_PRIMARY_SALT,
+                BODY_ROOF_DETAIL_SALT
+        ) * 0.5D + 0.5D;
+        return StrictMath.max(0.125D, 1D - normalized * worm.roofVariation());
+    }
+
+    private double bodyField(
+            ReachPosition position,
+            RiverWorm worm,
+            long primarySalt,
+            long detailSalt
+    ) {
+        double primary = perlin(
+                position.x(),
+                position.z(),
+                worm.bodyWavelength(),
+                worm.seed() ^ primarySalt
+        );
+        double detail = perlin(
+                position.x(),
+                position.z(),
+                worm.bodyDetailWavelength(),
+                worm.seed() ^ detailSalt
+        );
+        return primary * 0.7D + detail * 0.3D;
     }
 
     private FlowTangent resolveFlowTangent(RiverNode node, RiverTerrainSampler terrain) {
@@ -771,16 +712,6 @@ public final class RiverNetwork {
         return options.flowAlignmentWeight() * (1D - StrictMath.min(1D, alignment));
     }
 
-    private double smoothEdgeNoise(RiverEdgeId id, double position) {
-        int lower = (int) StrictMath.floor(position);
-        int upper = lower + 1;
-        double fraction = position - lower;
-        double fade = fraction * fraction * (3.0 - 2.0 * fraction);
-        double a = centered(mix(options.seed() ^ id.stableId() ^ MEANDER_SALT ^ lower * 0x9E3779B97F4A7C15L));
-        double b = centered(mix(options.seed() ^ id.stableId() ^ MEANDER_SALT ^ upper * 0x9E3779B97F4A7C15L));
-        return a + (b - a) * fade;
-    }
-
     private boolean intersects(
             RiverReach reach,
             long minimumX,
@@ -812,8 +743,8 @@ public final class RiverNetwork {
             long maximumZ
     ) {
         double length = StrictMath.hypot(to.x() - from.x(), to.z() - from.z());
-        double maximumMeander = StrictMath.min(options.meanderStrength(), length * 0.35D);
-        double padding = options.maximumReachRadius() + maximumMeander;
+        double maximumWormOffset = StrictMath.min(options.maximumWormOffset(), length * 0.35D);
+        double padding = options.maximumReachRadius() + maximumWormOffset;
         double reachMinimumX = StrictMath.min(from.x(), to.x()) - padding;
         double reachMaximumX = StrictMath.max(from.x(), to.x()) + padding;
         double reachMinimumZ = StrictMath.min(from.z(), to.z()) - padding;
@@ -825,8 +756,8 @@ public final class RiverNetwork {
     private int geometryPaddingCells() {
         double maximumEdgeAxisDelta = options.cellSize() * (1D + options.siteJitter());
         double maximumEdgeLength = StrictMath.sqrt(2D) * maximumEdgeAxisDelta;
-        double maximumMeander = StrictMath.min(options.meanderStrength(), maximumEdgeLength * 0.35D);
-        double displacement = options.maximumReachRadius() + maximumMeander;
+        double maximumWormOffset = StrictMath.min(options.maximumWormOffset(), maximumEdgeLength * 0.35D);
+        double displacement = options.maximumReachRadius() + maximumWormOffset;
         return 1 + (int) StrictMath.ceil(displacement / options.cellSize());
     }
 
@@ -917,7 +848,12 @@ public final class RiverNetwork {
         private final Map<RiverEdgeId, RiverRoutingContext> routingContexts;
         private final Map<RiverNodeId, FlowTangent> flowTangents;
         private final Map<RiverEdgeId, Integer> branchSlots;
+        private final Map<RiverNodeId, Double> styleDistances;
+        private final Map<RiverNodeId, StyleParent> styleParents;
+        private final Map<RiverNodeId, RiverWorm> styleWorms;
+        private final Map<RiverEdgeId, Integer> styleBranchSlots;
         private final Map<RiverNodeId, Boolean> resolvedBranchParents;
+        private final Map<RiverNodeId, Boolean> resolvedStyleBranchParents;
 
         private NodeResolver(RiverTerrainSampler terrain) {
             this.terrain = terrain;
@@ -932,7 +868,12 @@ public final class RiverNetwork {
             routingContexts = new HashMap<>();
             flowTangents = new HashMap<>();
             branchSlots = new HashMap<>();
+            styleDistances = new HashMap<>();
+            styleParents = new HashMap<>();
+            styleWorms = new HashMap<>();
+            styleBranchSlots = new HashMap<>();
             resolvedBranchParents = new HashMap<>();
+            resolvedStyleBranchParents = new HashMap<>();
         }
 
         private RiverNode resolve(RiverNodeId id) {
@@ -1099,11 +1040,88 @@ public final class RiverNetwork {
 
         private RiverRoutingContext routingContext(RiverNode from, RiverNode to) {
             RiverEdgeId edgeId = RiverEdgeId.of(from.id(), to.id());
+            RiverWorm worm = worm(from, to);
             return routingContexts.computeIfAbsent(edgeId, ignored -> RiverRoutingContext.lazy(
                     edgeId,
                     from,
                     to,
-                    () -> createPolyline(edgeId, from, to, this)));
+                    () -> createPolyline(from, to, worm)));
+        }
+
+        private RiverWorm worm(RiverNode first, RiverNode second) {
+            RiverNode child = compareRank(first, second) > 0 ? first : second;
+            return styleWorm(child.id());
+        }
+
+        private RiverWorm styleWorm(RiverNodeId id) {
+            RiverWorm cached = styleWorms.get(id);
+            if (cached != null) {
+                return cached;
+            }
+            StyleParent parent = styleParent(id);
+            RiverWorm selected;
+            if (parent.id() == null) {
+                selected = rootWormFor(id);
+            } else {
+                RiverWorm parentWorm = styleWorm(parent.id());
+                selected = childWormFor(
+                        parentWorm,
+                        parent.id(),
+                        id,
+                        styleBranchSlot(parent.id(), id)
+                );
+            }
+            styleWorms.put(id, selected);
+            return selected;
+        }
+
+        private StyleParent styleParent(RiverNodeId id) {
+            return styleParents.computeIfAbsent(id, nodeId -> {
+                double nodeDistance = styleDistance(nodeId);
+                RiverNodeId selected = null;
+                double selectedDistance = Double.POSITIVE_INFINITY;
+                for (RiverNodeId candidate : neighbors(nodeId)) {
+                    double candidateDistance = styleDistance(candidate);
+                    if (candidateDistance >= nodeDistance - 0.000000001D) {
+                        continue;
+                    }
+                    if (candidateDistance < selectedDistance
+                            || candidateDistance == selectedDistance
+                            && (selected == null || candidate.compareTo(selected) < 0)) {
+                        selected = candidate;
+                        selectedDistance = candidateDistance;
+                    }
+                }
+                return new StyleParent(selected);
+            });
+        }
+
+        private double styleDistance(RiverNodeId id) {
+            return styleDistances.computeIfAbsent(id, RiverNetwork.this::drainageDistance);
+        }
+
+        private int styleBranchSlot(RiverNodeId parentId, RiverNodeId childId) {
+            if (!resolvedStyleBranchParents.containsKey(parentId)) {
+                ArrayList<RiverNodeId> children = new ArrayList<>(8);
+                for (RiverNodeId candidate : neighbors(parentId)) {
+                    StyleParent candidateParent = styleParent(candidate);
+                    if (parentId.equals(candidateParent.id())) {
+                        children.add(candidate);
+                    }
+                }
+                children.sort((first, second) -> {
+                    long firstPriority = hash(RiverEdgeId.of(first, parentId), BRANCH_SLOT_SALT);
+                    long secondPriority = hash(RiverEdgeId.of(second, parentId), BRANCH_SLOT_SALT);
+                    int priorityComparison = Long.compareUnsigned(firstPriority, secondPriority);
+                    return priorityComparison != 0 ? priorityComparison : first.compareTo(second);
+                });
+                for (int slot = 0; slot < children.size(); slot++) {
+                    RiverNodeId child = children.get(slot);
+                    styleBranchSlots.put(RiverEdgeId.of(child, parentId), slot);
+                }
+                resolvedStyleBranchParents.put(parentId, true);
+            }
+            return styleBranchSlots.getOrDefault(RiverEdgeId.of(childId, parentId), Integer.MAX_VALUE);
         }
 
         private FlowTangent flowTangent(RiverNode node) {
@@ -1122,27 +1140,13 @@ public final class RiverNetwork {
     private record FlowTangent(double x, double z) {
     }
 
-    private record MeanderProfile(
-            MeanderPersonality personality,
-            double amplitude,
-            double handedness,
-            double phase,
-            double skew,
-            double cycles,
-            double featureA,
-            double featureB
-    ) {
+    private record DrainageBasinId(long x, long z) {
     }
 
-    private enum MeanderPersonality {
-        QUIET,
-        SWEEP,
-        HOOK,
-        S_CURVE,
-        COIL,
-        WANDER,
-        OXBOW,
-        CHIRP
+    private record DrainageBasin(DrainageBasinId id, double distance) {
+    }
+
+    private record StyleParent(RiverNodeId id) {
     }
 
     private record SourceTileId(long tileX, long tileZ) {
@@ -1156,6 +1160,7 @@ public final class RiverNetwork {
         private final RiverNode from;
         private final RiverNode to;
         private final RiverRoutingContext context;
+        private final RiverWorm worm;
         private final RiverTerrainSampler terrain;
         private int wetFlow;
         private int dryFlow;
@@ -1167,12 +1172,14 @@ public final class RiverNetwork {
                 RiverNode from,
                 RiverNode to,
                 RiverRoutingContext context,
+                RiverWorm worm,
                 RiverTerrainSampler terrain
         ) {
             this.id = id;
             this.from = from;
             this.to = to;
             this.context = context;
+            this.worm = worm;
             this.terrain = terrain;
         }
 
@@ -1193,21 +1200,7 @@ public final class RiverNetwork {
         private RiverReach build() {
             int flow = wetFlow + dryFlow;
             int order = 1 + (31 - Integer.numberOfLeadingZeros(flow));
-            double bankWidth = nonNegativeOrFallback(
-                    terrain.bankWidth(context, options.bankWidth()),
-                    options.bankWidth()
-            );
-            double baseDepth = positiveOrFallback(
-                    terrain.depth(context, options.depth()),
-                    options.depth()
-            );
-            RiverWidthProfile widthProfile = widthProfile(order);
-            double width = widthProfile.maximum();
-            bankWidth = StrictMath.min(options.maxBankWidth(), bankWidth);
-            double depth = StrictMath.min(
-                    options.maxDepth(),
-                    baseDepth * (1.0 + options.orderDepthFactor() * (order - 1))
-            );
+            RiverBodyProfile bodyProfile = bodyProfile(order, worm);
             RiverRouteState state = wetFlow > 0 ? RiverRouteState.WET : RiverRouteState.DRY;
             return new RiverReach(
                     id,
@@ -1216,10 +1209,10 @@ public final class RiverNetwork {
                     state,
                     flow,
                     order,
-                    width,
-                    widthProfile,
-                    bankWidth,
-                    depth,
+                    bodyProfile.maximumWidth(),
+                    bodyProfile.maximumBankWidth(),
+                    bodyProfile.maximumDepth(),
+                    bodyProfile,
                     state == RiverRouteState.WET && to.ocean(),
                     state == RiverRouteState.WET
                             ? terminalWetFlow == wetFlow
@@ -1228,12 +1221,21 @@ public final class RiverNetwork {
             );
         }
 
-        private RiverWidthProfile widthProfile(int order) {
+        private RiverBodyProfile bodyProfile(int order, RiverWorm worm) {
             RiverPolyline polyline = context.polyline();
-            int sampleCount = Math.min(WIDTH_PROFILE_SAMPLES, Math.max(2, polyline.size()));
+            double minimumWavelength = StrictMath.min(worm.bodyWavelength(), worm.bodyDetailWavelength());
+            int resolvedSamples = 1 + (int) StrictMath.ceil(polyline.length() * 2D / minimumWavelength);
+            int sampleCount = StrictMath.max(
+                    MINIMUM_BODY_PROFILE_SAMPLES,
+                    StrictMath.min(MAXIMUM_BODY_PROFILE_SAMPLES, resolvedSamples)
+            );
             double[] positions = new double[sampleCount];
             double[] widths = new double[sampleCount];
-            double orderScale = 1D + options.orderWidthFactor() * (order - 1);
+            double[] bankWidths = new double[sampleCount];
+            double[] depths = new double[sampleCount];
+            double[] roofScales = new double[sampleCount];
+            double widthOrderScale = 1D + options.orderWidthFactor() * (order - 1);
+            double depthOrderScale = 1D + options.orderDepthFactor() * (order - 1);
             for (int index = 0; index < sampleCount; index++) {
                 double alongReach = (double) index / (sampleCount - 1);
                 ReachPosition position = positionAt(polyline, alongReach);
@@ -1249,10 +1251,59 @@ public final class RiverNetwork {
                 positions[index] = alongReach;
                 widths[index] = StrictMath.min(
                         options.maxChannelWidth(),
-                        StrictMath.max(1D, baseWidth * orderScale)
+                        StrictMath.max(
+                                1D,
+                                baseWidth
+                                        * widthOrderScale
+                                        * worm.widthMultiplier()
+                                        * bodyMultiplier(
+                                                position,
+                                                worm,
+                                                BODY_WIDTH_PRIMARY_SALT,
+                                                BODY_WIDTH_DETAIL_SALT,
+                                                worm.widthVariation()
+                                        )
+                        )
                 );
+                double baseBankWidth = nonNegativeOrFallback(
+                        terrain.bankWidth(context, position.x(), position.z(), options.bankWidth()),
+                        options.bankWidth()
+                );
+                bankWidths[index] = StrictMath.min(
+                        options.maxBankWidth(),
+                        baseBankWidth
+                                * worm.bankMultiplier()
+                                * bodyMultiplier(
+                                        position,
+                                        worm,
+                                        BODY_BANK_PRIMARY_SALT,
+                                        BODY_BANK_DETAIL_SALT,
+                                        worm.bankVariation()
+                                )
+                );
+                double baseDepth = positiveOrFallback(
+                        terrain.depth(context, position.x(), position.z(), options.depth()),
+                        options.depth()
+                );
+                depths[index] = StrictMath.min(
+                        options.maxDepth(),
+                        StrictMath.max(
+                                1D,
+                                baseDepth
+                                        * depthOrderScale
+                                        * worm.depthMultiplier()
+                                        * bodyMultiplier(
+                                                position,
+                                                worm,
+                                                BODY_DEPTH_PRIMARY_SALT,
+                                                BODY_DEPTH_DETAIL_SALT,
+                                                worm.depthVariation()
+                                        )
+                        )
+                );
+                roofScales[index] = roofScale(position, worm);
             }
-            return new RiverWidthProfile(positions, widths);
+            return new RiverBodyProfile(positions, widths, bankWidths, depths, roofScales);
         }
     }
 

core/src/main/java/art/arcane/iris/engine/river/RiverNetworkOptions.java

@@ -1,5 +1,9 @@
 package art.arcane.iris.engine.river;
 
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
 public record RiverNetworkOptions(
         long seed,
         int cellSize,
@@ -21,8 +25,6 @@ public record RiverNetworkOptions(
         double routingNoiseWeight,
         double flowAlignmentWeight,
         double confluenceWeight,
-        int branchSoftCap,
-        double branchChildShrinkFactor,
         double oceanAttraction,
         double channelWidth,
         double bankWidth,
@@ -33,8 +35,7 @@ public record RiverNetworkOptions(
         double orderWidthFactor,
         double orderDepthFactor,
         double maximumReachRadius,
-        double meanderStrength,
-        int meanderSubdivisions
+        List<RiverWorm> worms
 ) {
     public RiverNetworkOptions {
         requireRange(cellSize, 8, 4096, "cellSize");
@@ -47,7 +48,6 @@ public record RiverNetworkOptions(
         requireRange(routingDeviationStrengthCells, 0D, 32D, "routingDeviationStrengthCells");
         requirePositive(routingPlateauHeight, "routingPlateauHeight");
         requireFinite(hydraulicBaseHeight, "hydraulicBaseHeight");
-        requireRange(meanderSubdivisions, 1, 64, "meanderSubdivisions");
         requireProbability(siteJitter, "siteJitter");
         requireProbability(sourceChance, "sourceChance");
         requireProbability(reachChance, "reachChance");
@@ -56,8 +56,6 @@ public record RiverNetworkOptions(
         requireFiniteNonNegative(routingNoiseWeight, "routingNoiseWeight");
         requireFiniteNonNegative(flowAlignmentWeight, "flowAlignmentWeight");
         requireFiniteNonNegative(confluenceWeight, "confluenceWeight");
-        requireRange(branchSoftCap, 1, 8, "branchSoftCap");
-        requireProbability(branchChildShrinkFactor, "branchChildShrinkFactor");
         requireFiniteNonNegative(oceanAttraction, "oceanAttraction");
         requirePositive(channelWidth, "channelWidth");
         requireFiniteNonNegative(bankWidth, "bankWidth");
@@ -68,15 +66,27 @@ public record RiverNetworkOptions(
         requireFiniteNonNegative(orderWidthFactor, "orderWidthFactor");
         requireFiniteNonNegative(orderDepthFactor, "orderDepthFactor");
         requireFiniteNonNegative(maximumReachRadius, "maximumReachRadius");
-        requireFiniteNonNegative(meanderStrength, "meanderStrength");
+        if (worms == null || worms.isEmpty()) {
+            throw new IllegalArgumentException("worms must contain at least one profile");
+        }
+        if (worms.size() > 16) {
+            throw new IllegalArgumentException("worms must contain at most 16 root profiles");
+        }
+        Set<String> ids = new HashSet<String>();
+        Set<Long> seeds = new HashSet<Long>();
+        int wormCount = validateWormTree(worms, 1, ids, seeds);
+        if (wormCount > 128) {
+            throw new IllegalArgumentException("worm hierarchy must contain at most 128 profiles");
+        }
+        worms = List.copyOf(worms);
         RiverTopologyComplexity.requireSafe(
                 cellSize,
                 tileCells,
                 siteJitter,
                 maxRouteReaches,
                 maximumReachRadius,
-                meanderStrength,
-                meanderSubdivisions
+                maximumWormOffset(worms),
+                maximumWormSegments(worms)
         );
     }
 
@@ -84,6 +94,66 @@ public record RiverNetworkOptions(
         return new Builder(seed);
     }
 
+    public double maximumWormOffset() {
+        return maximumWormOffset(worms);
+    }
+
+    public int maximumWormSegments() {
+        return maximumWormSegments(worms);
+    }
+
+    private static double maximumWormOffset(List<RiverWorm> worms) {
+        double maximum = 0D;
+        for (RiverWorm worm : worms) {
+            if (worm == null) {
+                throw new IllegalArgumentException("worms must not contain null profiles");
+            }
+            maximum = StrictMath.max(maximum, worm.maxOffset());
+            maximum = StrictMath.max(maximum, maximumWormOffset(worm.children()));
+        }
+        return maximum;
+    }
+
+    private static int maximumWormSegments(List<RiverWorm> worms) {
+        int maximum = 1;
+        for (RiverWorm worm : worms) {
+            if (worm == null) {
+                throw new IllegalArgumentException("worms must not contain null profiles");
+            }
+            maximum = StrictMath.max(maximum, worm.segments());
+            maximum = StrictMath.max(maximum, maximumWormSegments(worm.children()));
+        }
+        return maximum;
+    }
+
+    private static int validateWormTree(
+            List<RiverWorm> worms,
+            int depth,
+            Set<String> ids,
+            Set<Long> seeds
+    ) {
+        if (depth > 4) {
+            throw new IllegalArgumentException("worm hierarchy must be at most 4 profiles deep");
+        }
+        int count = 0;
+        for (RiverWorm worm : worms) {
+            if (worm == null) {
+                throw new IllegalArgumentException("worm hierarchy must not contain null profiles");
+            }
+            if (!ids.add(worm.id())) {
+                throw new IllegalArgumentException("worm ids must be unique: " + worm.id());
+            }
+            if (!seeds.add(worm.seed())) {
+                throw new IllegalArgumentException("worm seeds must be unique: " + worm.seed());
+            }
+            count++;
+            if (!worm.children().isEmpty()) {
+                count += validateWormTree(worm.children(), depth + 1, ids, seeds);
+            }
+        }
+        return count;
+    }
+
     private static void requireRange(int value, int minimum, int maximum, String name) {
         if (value < minimum || value > maximum) {
             throw new IllegalArgumentException(name + " must be between " + minimum + " and " + maximum);
@@ -141,8 +211,6 @@ public record RiverNetworkOptions(
         private double routingNoiseWeight;
         private double flowAlignmentWeight;
         private double confluenceWeight;
-        private int branchSoftCap;
-        private double branchChildShrinkFactor;
         private double oceanAttraction;
         private double channelWidth;
         private double bankWidth;
@@ -153,8 +221,7 @@ public record RiverNetworkOptions(
         private double orderWidthFactor;
         private double orderDepthFactor;
         private double maximumReachRadius;
-        private double meanderStrength;
-        private int meanderSubdivisions;
+        private List<RiverWorm> worms;
 
         private Builder(long seed) {
             this.seed = seed;
@@ -177,8 +244,6 @@ public record RiverNetworkOptions(
             routingNoiseWeight = 24.0;
             flowAlignmentWeight = 0D;
             confluenceWeight = 0D;
-            branchSoftCap = 4;
-            branchChildShrinkFactor = 0.35D;
             oceanAttraction = 64.0;
             channelWidth = 10.0;
             bankWidth = 8.0;
@@ -189,8 +254,32 @@ public record RiverNetworkOptions(
             orderWidthFactor = 0.35;
             orderDepthFactor = 0.2;
             maximumReachRadius = Double.NaN;
-            meanderStrength = 40.0;
-            meanderSubdivisions = 8;
+            worms = List.of(new RiverWorm(
+                    "default",
+                    1L,
+                    1D,
+                    1024D,
+                    256D,
+                    0.5D,
+                    0.15D,
+                    40D,
+                    8,
+                    1D,
+                    1D,
+                    1D,
+                    512D,
+                    128D,
+                    0D,
+                    0D,
+                    0D,
+                    0D,
+                    4,
+                    0.35D,
+                    1D,
+                    0D,
+                    0D,
+                    List.of()
+            ));
         }
 
         public Builder cellSize(int value) {
@@ -288,16 +377,6 @@ public record RiverNetworkOptions(
             return this;
         }
 
-        public Builder branchSoftCap(int value) {
-            branchSoftCap = value;
-            return this;
-        }
-
-        public Builder branchChildShrinkFactor(double value) {
-            branchChildShrinkFactor = value;
-            return this;
-        }
-
         public Builder oceanAttraction(double value) {
             oceanAttraction = value;
             return this;
@@ -348,13 +427,8 @@ public record RiverNetworkOptions(
             return this;
         }
 
-        public Builder meanderStrength(double value) {
-            meanderStrength = value;
-            return this;
-        }
-
-        public Builder meanderSubdivisions(int value) {
-            meanderSubdivisions = value;
+        public Builder worms(List<RiverWorm> value) {
+            worms = value;
             return this;
         }
 
@@ -383,8 +457,6 @@ public record RiverNetworkOptions(
                     routingNoiseWeight,
                     flowAlignmentWeight,
                     confluenceWeight,
-                    branchSoftCap,
-                    branchChildShrinkFactor,
                     oceanAttraction,
                     channelWidth,
                     bankWidth,
@@ -395,8 +467,7 @@ public record RiverNetworkOptions(
                     orderWidthFactor,
                     orderDepthFactor,
                     resolvedMaximumReachRadius,
-                    meanderStrength,
-                    meanderSubdivisions
+                    worms
             );
         }
 

core/src/main/java/art/arcane/iris/engine/river/RiverReach.java

@@ -10,9 +10,9 @@ public record RiverReach(
         int flow,
         int order,
         double width,
-        RiverWidthProfile widthProfile,
         double bankWidth,
         double depth,
+        RiverBodyProfile bodyProfile,
         boolean mouth,
         boolean terminal,
         RiverPolyline polyline
@@ -22,7 +22,7 @@ public record RiverReach(
         Objects.requireNonNull(from);
         Objects.requireNonNull(to);
         Objects.requireNonNull(state);
-        Objects.requireNonNull(widthProfile);
+        Objects.requireNonNull(bodyProfile);
         Objects.requireNonNull(polyline);
         if (state == RiverRouteState.SUPPRESSED) {
             throw new IllegalArgumentException("Suppressed routes cannot produce reaches");
@@ -34,12 +34,26 @@ public record RiverReach(
                 || !Double.isFinite(depth) || depth <= 0.0) {
             throw new IllegalArgumentException("River reach dimensions must be finite and valid");
         }
-        if (Double.compare(width, widthProfile.maximum()) != 0) {
-            throw new IllegalArgumentException("River reach width must equal its profile maximum");
+        if (Double.compare(width, bodyProfile.maximumWidth()) != 0
+                || Double.compare(bankWidth, bodyProfile.maximumBankWidth()) != 0
+                || Double.compare(depth, bodyProfile.maximumDepth()) != 0) {
+            throw new IllegalArgumentException("River reach dimensions must equal their body-profile maxima");
         }
     }
 
     public double widthAt(double alongReach) {
-        return widthProfile.sample(alongReach);
+        return bodyProfile.width(alongReach);
+    }
+
+    public double bankWidthAt(double alongReach) {
+        return bodyProfile.bankWidth(alongReach);
+    }
+
+    public double depthAt(double alongReach) {
+        return bodyProfile.depth(alongReach);
+    }
+
+    public double roofScaleAt(double alongReach) {
+        return bodyProfile.roofScale(alongReach);
     }
 }

core/src/main/java/art/arcane/iris/engine/river/RiverTerrainSampler.java

@@ -50,10 +50,6 @@ public interface RiverTerrainSampler {
         return 0.0;
     }
 
-    default double meanderNoise(RiverMeanderContext context) {
-        return Double.NaN;
-    }
-
     default double flowNoise(double x, double z) {
         return Double.NaN;
     }
@@ -75,10 +71,28 @@ public interface RiverTerrainSampler {
         return fallback;
     }
 
+    default double bankWidth(
+            RiverRoutingContext context,
+            double x,
+            double z,
+            double fallback
+    ) {
+        return bankWidth(context, fallback);
+    }
+
     default double depth(RiverRoutingContext context, double fallback) {
         return fallback;
     }
 
+    default double depth(
+            RiverRoutingContext context,
+            double x,
+            double z,
+            double fallback
+    ) {
+        return depth(context, fallback);
+    }
+
     default RiverTerminalPolicy terminalPolicy(int blockX, int blockZ) {
         return RiverTerminalPolicy.INHERIT;
     }

core/src/main/java/art/arcane/iris/engine/river/RiverTile.java

@@ -210,9 +210,11 @@ public final class RiverTile {
 
         double distance = StrictMath.sqrt(nearestDistanceSquared);
         double localWidth = nearestReach.widthAt(nearestAlongReach);
+        double localBankWidth = nearestReach.bankWidthAt(nearestAlongReach);
+        double localDepth = nearestReach.depthAt(nearestAlongReach);
         double channelRadius = localWidth * 0.5;
         RiverSection section = section(nearestReach, distance, channelRadius);
-        double carveWeight = carveWeight(distance, channelRadius, nearestReach.bankWidth());
+        double carveWeight = carveWeight(distance, channelRadius, localBankWidth);
         return new RiverSample(
                 true,
                 nearestReach.state(),
@@ -223,8 +225,8 @@ public final class RiverTile {
                 nearestReach.flow(),
                 nearestReach.order(),
                 localWidth,
-                nearestReach.bankWidth(),
-                nearestReach.depth(),
+                localBankWidth,
+                localDepth,
                 nearestReach.terminal(),
                 nearestReach.id()
         );
@@ -325,7 +327,7 @@ public final class RiverTile {
         RiverPolyline polyline = reach.polyline();
         if (polyline.length() == 0D) {
             double distanceSquared = squared(x - polyline.x(0)) + squared(z - polyline.z(0));
-            double radius = reach.widthAt(0D) * 0.5D + reach.bankWidth() + additionalRadius;
+            double radius = reach.widthAt(0D) * 0.5D + reach.bankWidthAt(0D) + additionalRadius;
             return distanceSquared <= radius * radius ? new ClosestPoint(distanceSquared, 0D) : null;
         }
         double nearest = Double.POSITIVE_INFINITY;
@@ -339,9 +341,9 @@ public final class RiverTile {
             }
             double deltaX = polyline.x(point + 1) - polyline.x(point);
             double deltaZ = polyline.z(point + 1) - polyline.z(point);
-            for (int profileIndex = 0; profileIndex < reach.widthProfile().size() - 1; profileIndex++) {
-                double profileStart = reach.widthProfile().position(profileIndex);
-                double profileEnd = reach.widthProfile().position(profileIndex + 1);
+            for (int profileIndex = 0; profileIndex < reach.bodyProfile().size() - 1; profileIndex++) {
+                double profileStart = reach.bodyProfile().position(profileIndex);
+                double profileEnd = reach.bodyProfile().position(profileIndex + 1);
                 double overlapStart = StrictMath.max(segmentStartAlong, profileStart);
                 double overlapEnd = StrictMath.min(segmentEndAlong, profileEnd);
                 if (overlapStart > overlapEnd) {
@@ -349,13 +351,16 @@ public final class RiverTile {
                 }
                 double intervalStart = (overlapStart - segmentStartAlong) / segmentAlongSpan;
                 double intervalEnd = (overlapEnd - segmentStartAlong) / segmentAlongSpan;
-                double widthSlope = (reach.widthProfile().width(profileIndex + 1)
-                        - reach.widthProfile().width(profileIndex)) / (profileEnd - profileStart);
-                double radiusBase = (reach.widthProfile().width(profileIndex)
+                double widthSlope = (reach.bodyProfile().widthAtIndex(profileIndex + 1)
+                        - reach.bodyProfile().widthAtIndex(profileIndex)) / (profileEnd - profileStart);
+                double bankSlope = (reach.bodyProfile().bankWidthAtIndex(profileIndex + 1)
+                        - reach.bodyProfile().bankWidthAtIndex(profileIndex)) / (profileEnd - profileStart);
+                double radiusBase = (reach.bodyProfile().widthAtIndex(profileIndex)
                         + widthSlope * (segmentStartAlong - profileStart)) * 0.5D
-                        + reach.bankWidth()
+                        + reach.bodyProfile().bankWidthAtIndex(profileIndex)
+                        + bankSlope * (segmentStartAlong - profileStart)
                         + additionalRadius;
-                double radiusSlope = widthSlope * segmentAlongSpan * 0.5D;
+                double radiusSlope = (widthSlope * 0.5D + bankSlope) * segmentAlongSpan;
                 ClosestPoint candidate = coveringPoint(
                         intervalStart,
                         intervalEnd,
@@ -394,7 +399,7 @@ public final class RiverTile {
                     maximumX,
                     maximumZ
             );
-            double radius = reach.widthAt(0D) * 0.5D + reach.bankWidth();
+            double radius = reach.widthAt(0D) * 0.5D + reach.bankWidthAt(0D);
             return distanceSquared <= radius * radius ? new ClosestPoint(distanceSquared, 0D) : null;
         }
         double nearest = Double.POSITIVE_INFINITY;
@@ -410,9 +415,9 @@ public final class RiverTile {
             double startZ = polyline.z(point);
             double deltaX = polyline.x(point + 1) - startX;
             double deltaZ = polyline.z(point + 1) - startZ;
-            for (int profileIndex = 0; profileIndex < reach.widthProfile().size() - 1; profileIndex++) {
-                double profileStart = reach.widthProfile().position(profileIndex);
-                double profileEnd = reach.widthProfile().position(profileIndex + 1);
+            for (int profileIndex = 0; profileIndex < reach.bodyProfile().size() - 1; profileIndex++) {
+                double profileStart = reach.bodyProfile().position(profileIndex);
+                double profileEnd = reach.bodyProfile().position(profileIndex + 1);
                 double overlapStart = StrictMath.max(segmentStartAlong, profileStart);
                 double overlapEnd = StrictMath.min(segmentEndAlong, profileEnd);
                 if (overlapStart > overlapEnd) {
@@ -420,11 +425,15 @@ public final class RiverTile {
                 }
                 double intervalStart = (overlapStart - segmentStartAlong) / segmentAlongSpan;
                 double intervalEnd = (overlapEnd - segmentStartAlong) / segmentAlongSpan;
-                double widthSlope = (reach.widthProfile().width(profileIndex + 1)
-                        - reach.widthProfile().width(profileIndex)) / (profileEnd - profileStart);
-                double radiusBase = (reach.widthProfile().width(profileIndex)
-                        + widthSlope * (segmentStartAlong - profileStart)) * 0.5D + reach.bankWidth();
-                double radiusSlope = widthSlope * segmentAlongSpan * 0.5D;
+                double widthSlope = (reach.bodyProfile().widthAtIndex(profileIndex + 1)
+                        - reach.bodyProfile().widthAtIndex(profileIndex)) / (profileEnd - profileStart);
+                double bankSlope = (reach.bodyProfile().bankWidthAtIndex(profileIndex + 1)
+                        - reach.bodyProfile().bankWidthAtIndex(profileIndex)) / (profileEnd - profileStart);
+                double radiusBase = (reach.bodyProfile().widthAtIndex(profileIndex)
+                        + widthSlope * (segmentStartAlong - profileStart)) * 0.5D
+                        + reach.bodyProfile().bankWidthAtIndex(profileIndex)
+                        + bankSlope * (segmentStartAlong - profileStart);
+                double radiusSlope = (widthSlope * 0.5D + bankSlope) * segmentAlongSpan;
                 double cursor = intervalStart;
                 do {
                     double next = intervalEnd;

core/src/main/java/art/arcane/iris/engine/river/RiverTopologyComplexity.java

@@ -19,14 +19,12 @@ public final class RiverTopologyComplexity {
             double siteJitter,
             int maxRouteReaches,
             double maximumReachRadius,
-            double meanderStrength,
-            int meanderSubdivisions
+            double maximumWormOffset,
+            int maximumWormSegments
     ) {
         double maximumEdgeAxisDelta = cellSize * (1D + siteJitter);
-        double maximumEdgeLength = StrictMath.sqrt(2D) * maximumEdgeAxisDelta;
-        double maximumMeander = StrictMath.min(meanderStrength, maximumEdgeLength * 0.35D);
         long geometryPaddingCells = 1L + ceilToLong(
-                (maximumReachRadius + maximumMeander) / cellSize
+                (maximumReachRadius + maximumWormOffset) / cellSize
         );
         long targetWindowAxis = saturatedAdd(tileCells, saturatedMultiply(2L, geometryPaddingCells));
         long sourceWindowAxis = saturatedAdd(
@@ -36,7 +34,7 @@ public final class RiverTopologyComplexity {
         long sourceWindowCells = saturatedMultiply(sourceWindowAxis, sourceWindowAxis);
         long maximumRouteScanSteps = saturatedMultiply(sourceWindowCells, maxRouteReaches);
         double maximumSegmentSpan = maximumEdgeAxisDelta
-                + maximumMeander * 2D
+                + maximumWormOffset * 2D
                 + maximumReachRadius * 2D;
         long maximumSegmentBucketAxis = saturatedAdd(
                 ceilToLong(maximumSegmentSpan / SPATIAL_BUCKET_SIZE),
@@ -48,7 +46,7 @@ public final class RiverTopologyComplexity {
         );
         long maximumBucketWritesPerReach = saturatedMultiply(
                 maximumSegmentBucketCount,
-                meanderSubdivisions
+                maximumWormSegments
         );
         return new Estimate(
                 geometryPaddingCells,
@@ -66,8 +64,8 @@ public final class RiverTopologyComplexity {
             double siteJitter,
             int maxRouteReaches,
             double maximumReachRadius,
-            double meanderStrength,
-            int meanderSubdivisions
+            double maximumWormOffset,
+            int maximumWormSegments
     ) {
         Estimate estimate = estimate(
                 cellSize,
@@ -75,8 +73,8 @@ public final class RiverTopologyComplexity {
                 siteJitter,
                 maxRouteReaches,
                 maximumReachRadius,
-                meanderStrength,
-                meanderSubdivisions
+                maximumWormOffset,
+                maximumWormSegments
         );
         List<String> violations = estimate.violations();
         if (!violations.isEmpty()) {
@@ -205,7 +203,7 @@ public final class RiverTopologyComplexity {
                         + " bucket writes for one reach (" + maximumSegmentBucketAxis
                         + " buckets per segment axis), above the safe limit of "
                         + MAXIMUM_BUCKET_WRITES_PER_REACH
-                        + "; reduce channel width, bank width, orderWidthFactor, meanderStrength, or meanderSubdivisions.");
+                        + "; reduce channel width, bank width, orderWidthFactor, worm maxOffset, or worm segments.");
             }
             return List.copyOf(violations);
         }

core/src/main/java/art/arcane/iris/engine/river/RiverWidthProfile.java

@@ -1,89 +0,0 @@
-package art.arcane.iris.engine.river;
-
-import java.util.Arrays;
-
-public final class RiverWidthProfile {
-    private final double[] positions;
-    private final double[] widths;
-    private final double maximum;
-
-    public RiverWidthProfile(double[] positions, double[] widths) {
-        if (positions == null || widths == null || positions.length < 2 || positions.length != widths.length) {
-            throw new IllegalArgumentException("River width profiles require matching position and width samples");
-        }
-        this.positions = positions.clone();
-        this.widths = widths.clone();
-        double resolvedMaximum = 0D;
-        for (int index = 0; index < this.positions.length; index++) {
-            double position = this.positions[index];
-            double width = this.widths[index];
-            if (!Double.isFinite(position) || position < 0D || position > 1D
-                    || (index > 0 && position <= this.positions[index - 1])) {
-                throw new IllegalArgumentException("River width profile positions must increase from zero to one");
-            }
-            if (!Double.isFinite(width) || width <= 0D) {
-                throw new IllegalArgumentException("River width profile widths must be finite and positive");
-            }
-            resolvedMaximum = Math.max(resolvedMaximum, width);
-        }
-        if (this.positions[0] != 0D || this.positions[this.positions.length - 1] != 1D) {
-            throw new IllegalArgumentException("River width profile positions must include zero and one");
-        }
-        maximum = resolvedMaximum;
-    }
-
-    public static RiverWidthProfile constant(double width) {
-        return new RiverWidthProfile(new double[]{0D, 1D}, new double[]{width, width});
-    }
-
-    public double sample(double alongReach) {
-        double position = Math.max(0D, Math.min(1D, alongReach));
-        int index = Arrays.binarySearch(positions, position);
-        if (index >= 0) {
-            return widths[index];
-        }
-        int upper = -index - 1;
-        if (upper <= 0) {
-            return widths[0];
-        }
-        if (upper >= positions.length) {
-            return widths[widths.length - 1];
-        }
-        int lower = upper - 1;
-        double range = positions[upper] - positions[lower];
-        double interpolation = range <= 0D ? 0D : (position - positions[lower]) / range;
-        return widths[lower] + (widths[upper] - widths[lower]) * interpolation;
-    }
-
-    public double maximum() {
-        return maximum;
-    }
-
-    public int size() {
-        return widths.length;
-    }
-
-    public double position(int index) {
-        return positions[index];
-    }
-
-    public double width(int index) {
-        return widths[index];
-    }
-
-    @Override
-    public boolean equals(Object object) {
-        if (this == object) {
-            return true;
-        }
-        if (!(object instanceof RiverWidthProfile profile)) {
-            return false;
-        }
-        return Arrays.equals(positions, profile.positions) && Arrays.equals(widths, profile.widths);
-    }
-
-    @Override
-    public int hashCode() {
-        return 31 * Arrays.hashCode(positions) + Arrays.hashCode(widths);
-    }
-}

core/src/main/java/art/arcane/iris/engine/river/RiverWorm.java

@@ -0,0 +1,79 @@
+package art.arcane.iris.engine.river;
+
+import java.util.List;
+
+public record RiverWorm(
+        String id,
+        long seed,
+        double weight,
+        double wavelength,
+        double detailWavelength,
+        double tortuosity,
+        double detailTortuosity,
+        double maxOffset,
+        int segments,
+        double widthMultiplier,
+        double bankMultiplier,
+        double depthMultiplier,
+        double bodyWavelength,
+        double bodyDetailWavelength,
+        double widthVariation,
+        double bankVariation,
+        double depthVariation,
+        double roofVariation,
+        int branchCap,
+        double branchDecay,
+        double confluenceMultiplier,
+        double childChance,
+        double branchChildChance,
+        List<RiverWorm> children
+) {
+    public RiverWorm {
+        if (id == null || !id.matches("[a-z0-9][a-z0-9_-]{0,63}")) {
+            throw new IllegalArgumentException("id must use 1 to 64 lowercase letters, digits, underscores, or hyphens");
+        }
+        requireRange(weight, 0.000001D, 1000000D, "weight");
+        requireRange(wavelength, 8D, 16384D, "wavelength");
+        requireRange(detailWavelength, 8D, 16384D, "detailWavelength");
+        requireRange(tortuosity, 0D, 1D, "tortuosity");
+        requireRange(detailTortuosity, 0D, 1D, "detailTortuosity");
+        requireRange(maxOffset, 0D, 1024D, "maxOffset");
+        if (segments < 1 || segments > 64) {
+            throw new IllegalArgumentException("segments must be between 1 and 64");
+        }
+        requireRange(widthMultiplier, 0.125D, 8D, "widthMultiplier");
+        requireRange(bankMultiplier, 0.125D, 8D, "bankMultiplier");
+        requireRange(depthMultiplier, 0.125D, 8D, "depthMultiplier");
+        requireRange(bodyWavelength, 32D, 16384D, "bodyWavelength");
+        requireRange(bodyDetailWavelength, 32D, 16384D, "bodyDetailWavelength");
+        requireRange(widthVariation, 0D, 0.875D, "widthVariation");
+        requireRange(bankVariation, 0D, 0.875D, "bankVariation");
+        requireRange(depthVariation, 0D, 0.875D, "depthVariation");
+        requireRange(roofVariation, 0D, 0.875D, "roofVariation");
+        if (branchCap < 1 || branchCap > 8) {
+            throw new IllegalArgumentException("branchCap must be between 1 and 8");
+        }
+        requireRange(branchDecay, 0D, 1D, "branchDecay");
+        requireRange(confluenceMultiplier, 0D, 8D, "confluenceMultiplier");
+        requireRange(childChance, 0D, 1D, "childChance");
+        requireRange(branchChildChance, 0D, 1D, "branchChildChance");
+        if (children == null) {
+            throw new IllegalArgumentException("children must not be null");
+        }
+        if (children.size() > 16) {
+            throw new IllegalArgumentException("children must contain at most 16 profiles");
+        }
+        for (RiverWorm child : children) {
+            if (child == null) {
+                throw new IllegalArgumentException("children must not contain null profiles");
+            }
+        }
+        children = List.copyOf(children);
+    }
+
+    private static void requireRange(double value, double minimum, double maximum, String name) {
+        if (!Double.isFinite(value) || value < minimum || value > maximum) {
+            throw new IllegalArgumentException(name + " must be between " + minimum + " and " + maximum);
+        }
+    }
+}

core/src/main/java/art/arcane/iris/engine/river/runtime/IrisRiverRuntime.java

@@ -16,11 +16,11 @@ import art.arcane.iris.engine.object.IrisRiverTerrain;
 import art.arcane.iris.engine.object.IrisRiverTopology;
 import art.arcane.iris.engine.object.IrisRiverWater;
 import art.arcane.iris.engine.object.IrisRiverWaterMode;
+import art.arcane.iris.engine.object.IrisRiverWorm;
 import art.arcane.iris.engine.object.IrisStyledRange;
 import art.arcane.iris.engine.object.NoiseStyle;
 import art.arcane.iris.engine.river.RiverAnchor;
 import art.arcane.iris.engine.river.RiverEdgeId;
-import art.arcane.iris.engine.river.RiverMeanderContext;
 import art.arcane.iris.engine.river.RiverNetworkOptions;
 import art.arcane.iris.engine.river.RiverPolyline;
 import art.arcane.iris.engine.river.RiverReach;
@@ -35,6 +35,7 @@ import art.arcane.iris.engine.river.RiverTerminalPolicy;
 import art.arcane.iris.engine.river.RiverTile;
 import art.arcane.iris.engine.river.RiverTileCache;
 import art.arcane.iris.engine.river.RiverTopologyComplexity;
+import art.arcane.iris.engine.river.RiverWorm;
 import art.arcane.iris.util.project.interpolation.NoiseBounds;
 import art.arcane.iris.util.project.noise.CNG;
 import art.arcane.iris.util.project.stream.ProceduralStream;
@@ -61,7 +62,6 @@ public final class IrisRiverRuntime implements AutoCloseable {
     private static final long WIDTH_NOISE_SALT = 0xBE5466CF34E90C6CL;
     private static final long BANK_NOISE_SALT = 0xC0AC29B7C97C50DDL;
     private static final long DEPTH_NOISE_SALT = 0x3F84D5B5B5470917L;
-    private static final long MEANDER_NOISE_SALT = 0x9216D5D98979FB1BL;
     private static final long BED_NOISE_SALT = 0xD1310BA698DFB5ACL;
     private static final long BIOME_NOISE_SALT = 0x2FFD72DBD01ADFB7L;
     private static final long CAVE_ENTRY_NOISE_SALT = 0xB8E1AFED6A267E96L;
@@ -98,7 +98,6 @@ public final class IrisRiverRuntime implements AutoCloseable {
     private final CNG widthNoise;
     private final CNG bankNoise;
     private final CNG depthNoise;
-    private final CNG meanderNoise;
     private final CNG bedNoise;
     private final CNG biomeNoise;
     private final CNG caveEntryNoise;
@@ -144,7 +143,6 @@ public final class IrisRiverRuntime implements AutoCloseable {
         widthNoise = noise(terrain.getChannelWidth(), WIDTH_NOISE_SALT);
         bankNoise = noise(terrain.getBankWidth(), BANK_NOISE_SALT);
         depthNoise = noise(terrain.getDepth(), DEPTH_NOISE_SALT);
-        meanderNoise = noise(terrain.getMeanderStyle(), MEANDER_NOISE_SALT);
         bedNoise = noise(terrain.getBedRoughnessStyle(), BED_NOISE_SALT);
         biomeNoise = noise(configuration.getBiomes().getSelectionStyle(), BIOME_NOISE_SALT);
         caveEntryNoise = noise(caves.getEntry(), CAVE_ENTRY_NOISE_SALT);
@@ -256,7 +254,11 @@ public final class IrisRiverRuntime implements AutoCloseable {
                 z
         );
         int ceilingY = shapedTunnelCeilingY(
-                waterHeadY, caves.getDryHeadroom(), profile, roofOffset);
+                waterHeadY,
+                caves.getDryHeadroom() * column.reach().roofScaleAt(column.river().alongReach()),
+                profile,
+                roofOffset
+        );
         return new IrisRiverTunnelSample(column.river(), bedY, waterHeadY, ceilingY);
     }
 
@@ -349,7 +351,7 @@ public final class IrisRiverRuntime implements AutoCloseable {
         IrisBiome sampledBiome = naturalBiome.get(center.x(), center.z());
         double head = waterSurface(reach, alongReach, isNaturalOcean(sampledBiome));
         double centerNaturalHeight = naturalHeight.get(center.x(), center.z());
-        double centerBedHeight = head - reach.depth() + bedRoughness(center.x(), center.z());
+        double centerBedHeight = head - reach.depthAt(alongReach) + bedRoughness(center.x(), center.z());
         EffectiveRiverSettings settings = settingsFor(sampledRegion, sampledBiome);
         double maximumIncision = Math.max(0D, terrain.getMaxIncision() * settings.maxIncisionMultiplier());
         double cappedSurface = incisedHeight(centerNaturalHeight, centerBedHeight, 1D, maximumIncision);
@@ -627,8 +629,6 @@ public final class IrisRiverRuntime implements AutoCloseable {
                 .routingNoiseWeight(0D)
                 .flowAlignmentWeight(topology.getFlowAlignmentWeight())
                 .confluenceWeight(topology.getConfluenceWeight())
-                .branchSoftCap(topology.getBranchSoftCap())
-                .branchChildShrinkFactor(topology.getBranchChildShrinkFactor())
                 .oceanAttraction(topology.getOceanAttraction())
                 .channelWidth(mid(riverTerrain.getChannelWidth(), 12D))
                 .bankWidth(mid(riverTerrain.getBankWidth(), 8D))
@@ -639,11 +639,63 @@ public final class IrisRiverRuntime implements AutoCloseable {
                 .orderWidthFactor(riverTerrain.getOrderWidthFactor())
                 .orderDepthFactor(riverTerrain.getOrderDepthFactor())
                 .maximumReachRadius(maximumReachRadius(topology, riverTerrain))
-                .meanderStrength(riverTerrain.getMeanderStrength())
-                .meanderSubdivisions(riverTerrain.getMeanderSubdivisions())
+                .worms(worms(riverTerrain))
                 .build();
     }
 
+    private List<RiverWorm> worms(IrisRiverTerrain riverTerrain) {
+        if (riverTerrain.getWorms() == null || riverTerrain.getWorms().isEmpty()) {
+            throw new IllegalArgumentException("River terrain must configure at least one Perlin worm");
+        }
+        ArrayList<RiverWorm> worms = new ArrayList<>(riverTerrain.getWorms().size());
+        for (IrisRiverWorm configured : riverTerrain.getWorms()) {
+            if (configured == null) {
+                throw new IllegalArgumentException("River terrain worms must not contain null entries");
+            }
+            worms.add(worm(configured));
+        }
+        return List.copyOf(worms);
+    }
+
+    private RiverWorm worm(IrisRiverWorm configured) {
+        if (configured.getChildren() == null) {
+            throw new IllegalArgumentException("River worm children must be an array");
+        }
+        ArrayList<RiverWorm> children = new ArrayList<>(configured.getChildren().size());
+        for (IrisRiverWorm child : configured.getChildren()) {
+            if (child == null) {
+                throw new IllegalArgumentException("River worm children must not contain null entries");
+            }
+            children.add(worm(child));
+        }
+        return new RiverWorm(
+                configured.getId(),
+                configured.getSeed(),
+                configured.getWeight(),
+                configured.getWavelength(),
+                configured.getDetailWavelength(),
+                configured.getTortuosity(),
+                configured.getDetailTortuosity(),
+                configured.getMaxOffset(),
+                configured.getSegments(),
+                configured.getWidthMultiplier(),
+                configured.getBankMultiplier(),
+                configured.getDepthMultiplier(),
+                configured.getBodyWavelength(),
+                configured.getBodyDetailWavelength(),
+                configured.getWidthVariation(),
+                configured.getBankVariation(),
+                configured.getDepthVariation(),
+                configured.getRoofVariation(),
+                configured.getBranchCap(),
+                configured.getBranchDecay(),
+                configured.getConfluenceMultiplier(),
+                configured.getChildChance(),
+                configured.getBranchChildChance(),
+                List.copyOf(children)
+        );
+    }
+
     private void addTerminalCaveAnchors(
             RiverTile tile,
             int minimumX,
@@ -1141,11 +1193,6 @@ public final class IrisRiverRuntime implements AutoCloseable {
             return routingCost(context.midpointX(), context.midpointZ());
         }
 
-        @Override
-        public double meanderNoise(RiverMeanderContext context) {
-            return meanderNoise.fitDouble(-1D, 1D, context.x(), context.z());
-        }
-
         @Override
         public double flowNoise(double x, double z) {
             return routingNoise.fitDouble(-1D, 1D, x, z);
@@ -1183,6 +1230,18 @@ public final class IrisRiverRuntime implements AutoCloseable {
                     * settings.bankWidthMultiplier();
         }
 
+        @Override
+        public double bankWidth(RiverRoutingContext context, double x, double z, double fallback) {
+            EffectiveRiverSettings settings = settingsAt(x, z);
+            return styled(
+                    terrain.getBankWidth(),
+                    bankNoise,
+                    (int) StrictMath.round(x),
+                    (int) StrictMath.round(z),
+                    fallback
+            ) * settings.bankWidthMultiplier();
+        }
+
         @Override
         public double depth(RiverRoutingContext context, double fallback) {
             EffectiveRiverSettings settings = settingsAt(context.midpointX(), context.midpointZ());
@@ -1199,6 +1258,22 @@ public final class IrisRiverRuntime implements AutoCloseable {
             );
         }
 
+        @Override
+        public double depth(RiverRoutingContext context, double x, double z, double fallback) {
+            EffectiveRiverSettings settings = settingsAt(x, z);
+            double configuredDepth = styled(
+                    terrain.getDepth(),
+                    depthNoise,
+                    (int) StrictMath.round(x),
+                    (int) StrictMath.round(z),
+                    fallback
+            ) * settings.depthMultiplier();
+            return Math.min(
+                    terrain.getMaxDepth(),
+                    Math.max(1D + terrain.getBedRoughness(), configuredDepth)
+            );
+        }
+
         @Override
         public RiverTerminalPolicy terminalPolicy(int blockX, int blockZ) {
             EffectiveRiverSettings settings = settingsAt(blockX, blockZ);

core/src/main/java/art/arcane/iris/util/common/plugin/VolmitPlugin.java

@@ -50,19 +50,19 @@ public abstract class VolmitPlugin extends JavaPlugin implements Listener {
     }
 
     public void l(Object l) {
-        IrisLogging.info("[" + getName() + "]: " + l);
+        IrisLogging.info(String.valueOf(l));
     }
 
     public void w(Object l) {
-        IrisLogging.warn("[" + getName() + "]: " + l);
+        IrisLogging.warn(String.valueOf(l));
     }
 
     public void f(Object l) {
-        IrisLogging.error("[" + getName() + "]: " + l);
+        IrisLogging.error(String.valueOf(l));
     }
 
     public void v(Object l) {
-        IrisLogging.debug("[" + getName() + "]: " + l);
+        IrisLogging.debug(String.valueOf(l));
     }
 
     public void onEnable() {

core/src/test/java/art/arcane/iris/core/pack/PackRiverValidatorTest.java

@@ -25,6 +25,7 @@ public class PackRiverValidatorTest {
                   "logicalHeight": 256,
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "biomes": {
                       "channel": [],
                       "bank": [],
@@ -41,6 +42,212 @@ public class PackRiverValidatorTest {
         assertTrue(result.getBlockingErrors().toString(), result.isLoadable());
     }
 
+    @Test
+    public void acceptsRequiredValidWormProfiles() throws Exception {
+        File pack = pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {
+                      "worms": [
+                        {
+                          "id": "floodplain_trunk",
+                          "seed": 17,
+                          "weight": 2.5,
+                          "wavelength": 1536,
+                          "detailWavelength": 192,
+                          "tortuosity": 0.65,
+                          "detailTortuosity": 0.2,
+                          "maxOffset": 420,
+                          "segments": 56,
+                          "widthMultiplier": 1.4,
+                          "bankMultiplier": 1.2,
+                          "depthMultiplier": 0.8,
+                          "bodyWavelength": 1400,
+                          "bodyDetailWavelength": 320,
+                          "widthVariation": 0.65,
+                          "bankVariation": 0.75,
+                          "depthVariation": 0.45,
+                          "roofVariation": 0.55,
+                          "branchCap": 3,
+                          "branchDecay": 0.25,
+                          "confluenceMultiplier": 1.5,
+                          "childChance": 0.2,
+                          "branchChildChance": 0.6,
+                          "children": [
+                            {
+                              "id": "floodplain_tributary",
+                              "seed": 29,
+                              "weight": 1,
+                              "wavelength": 640,
+                              "detailWavelength": 128,
+                              "tortuosity": 0.8,
+                              "detailTortuosity": 0.3,
+                              "maxOffset": 300,
+                              "segments": 48,
+                              "widthMultiplier": 0.7,
+                              "bankMultiplier": 0.9,
+                              "depthMultiplier": 1.3,
+                              "bodyWavelength": 180,
+                              "bodyDetailWavelength": 48,
+                              "widthVariation": 0.8,
+                              "bankVariation": 0.8,
+                              "depthVariation": 0.65,
+                              "roofVariation": 0.75,
+                              "branchCap": 2,
+                              "branchDecay": 0.1,
+                              "confluenceMultiplier": 0.75,
+                              "childChance": 0,
+                              "branchChildChance": 0,
+                              "children": []
+                            }
+                          ]
+                        }
+                      ]
+                    }
+                  }
+                }
+                """);
+
+        PackRiverValidator.Validation result = validate(pack);
+
+        assertTrue(result.errors().toString(), result.errors().isEmpty());
+    }
+
+    @Test
+    public void rejectsInvalidWormHierarchyIdentifiersRangesAndChildren() throws Exception {
+        File pack = pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {
+                      "worms": [
+                        {
+                          "id": "trunk",
+                          "seed": 17,
+                          "bodyWavelength": 31,
+                          "bodyDetailWavelength": 16385,
+                          "widthVariation": -0.1,
+                          "bankVariation": 0.876,
+                          "depthVariation": -0.1,
+                          "roofVariation": 0.876,
+                          "branchCap": 0,
+                          "branchDecay": 2,
+                          "confluenceMultiplier": 9,
+                          "childChance": -0.1,
+                          "branchChildChance": 1.1,
+                          "children": "tributary"
+                        },
+                        {"id": "trunk", "seed": 29},
+                        {"id": "Bad ID", "seed": 31}
+                      ]
+                    }
+                  }
+                }
+                """);
+
+        PackRiverValidator.Validation result = validate(pack);
+
+        assertContains(result.errors(), "rivers.terrain.worms[0].bodyWavelength must be at least 32");
+        assertContains(result.errors(), "rivers.terrain.worms[0].bodyDetailWavelength must be at most 16384");
+        assertContains(result.errors(), "rivers.terrain.worms[0].widthVariation must be at least 0");
+        assertContains(result.errors(), "rivers.terrain.worms[0].bankVariation must be at most 0.875");
+        assertContains(result.errors(), "rivers.terrain.worms[0].depthVariation must be at least 0");
+        assertContains(result.errors(), "rivers.terrain.worms[0].roofVariation must be at most 0.875");
+        assertContains(result.errors(), "rivers.terrain.worms[0].branchCap must be at least 1");
+        assertContains(result.errors(), "rivers.terrain.worms[0].branchDecay must be at most 1");
+        assertContains(result.errors(), "rivers.terrain.worms[0].confluenceMultiplier must be at most 8");
+        assertContains(result.errors(), "rivers.terrain.worms[0].childChance must be at least 0");
+        assertContains(result.errors(), "rivers.terrain.worms[0].branchChildChance must be at most 1");
+        assertContains(result.errors(), "rivers.terrain.worms[0].children must be an array");
+        assertContains(result.errors(), "rivers.terrain.worms[1].id must be unique inside the worm hierarchy");
+        assertContains(result.errors(),
+                "rivers.terrain.worms[2].id must use 1 to 64 lowercase letters, digits, underscores, or hyphens");
+    }
+
+    @Test
+    public void rejectsWormHierarchyDepthAndProfileLimits() throws Exception {
+        File excessiveDepth = pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {
+                      "worms": [
+                        {
+                          "id": "level_1",
+                          "seed": 1,
+                          "children": [
+                            {
+                              "id": "level_2",
+                              "seed": 2,
+                              "children": [
+                                {
+                                  "id": "level_3",
+                                  "seed": 3,
+                                  "children": [
+                                    {
+                                      "id": "level_4",
+                                      "seed": 4,
+                                      "children": [
+                                        {"id": "level_5", "seed": 5}
+                                      ]
+                                    }
+                                  ]
+                                }
+                              ]
+                            }
+                          ]
+                        }
+                      ]
+                    }
+                  }
+                }
+                """);
+        File excessiveRoots = packWithWorms(wormHierarchy(17, 0));
+        File excessiveProfiles = packWithWorms(wormHierarchy(16, 8));
+
+        PackRiverValidator.Validation depthResult = validate(excessiveDepth);
+        PackRiverValidator.Validation rootResult = validate(excessiveRoots);
+        PackRiverValidator.Validation profileResult = validate(excessiveProfiles);
+
+        assertContains(depthResult.errors(), "children exceeds the maximum hierarchy depth of 4");
+        assertContains(rootResult.errors(), "rivers.terrain.worms must contain at most 16 root profiles");
+        assertContains(profileResult.errors(), "rivers.terrain.worms hierarchy must contain at most 128 profiles");
+    }
+
+    @Test
+    public void rejectsMissingAndEmptyWormLists() throws Exception {
+        File missing = pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {}
+                  }
+                }
+                """);
+        File empty = pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {"worms": []}
+                  }
+                }
+                """);
+
+        PackRiverValidator.Validation missingResult = validate(missing);
+        PackRiverValidator.Validation emptyResult = validate(empty);
+
+        assertContains(missingResult.errors(),
+                "rivers.terrain.worms must be an array with at least one Perlin-worm profile");
+        assertContains(emptyResult.errors(),
+                "rivers.terrain.worms must contain at least one Perlin-worm profile");
+    }
+
     @Test
     public void rejectsNullEnabledNetworkSections() throws Exception {
         File pack = pack("""
@@ -84,11 +291,10 @@ public class PackRiverValidatorTest {
                       "routingPlateauHeight": 0,
                       "flowAlignmentWeight": 1025,
                       "confluenceWeight": -1,
-                      "branchSoftCap": 9,
-                      "branchChildShrinkFactor": 2,
                       "routingStyle": {"zoom": 0}
                     },
                     "terrain": {
+                      "worms": [{"id": "river"}],
                       "channelWidth": {"min": 40, "max": 12},
                       "depth": {},
                       "tunnelWidthMultiplier": {"min": 0.5, "max": 9},
@@ -116,8 +322,6 @@ public class PackRiverValidatorTest {
         assertContains(result.errors(), "rivers.topology.routingPlateauHeight must be at least 1");
         assertContains(result.errors(), "rivers.topology.flowAlignmentWeight must be at most 1024");
         assertContains(result.errors(), "rivers.topology.confluenceWeight must be at least 0");
-        assertContains(result.errors(), "rivers.topology.branchSoftCap must be at most 8");
-        assertContains(result.errors(), "rivers.topology.branchChildShrinkFactor must be at most 1");
         assertContains(result.errors(), "rivers.topology.routingStyle.zoom must be at least");
         assertContains(result.errors(), "rivers.terrain.channelWidth.min must not exceed");
         assertContains(result.errors(), "rivers.terrain.depth must set min and max explicitly.");
@@ -138,6 +342,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "water": {
                       "mode": "TERRACED",
                       "maximumPoolRise": 2,
@@ -169,8 +374,7 @@ public class PackRiverValidatorTest {
                       "channelWidth": {"min": 2048, "max": 2048},
                       "bankWidth": {"min": 2048, "max": 2048},
                       "orderWidthFactor": 8,
-                      "meanderStrength": 1024,
-                      "meanderSubdivisions": 64
+                      "worms": [{"id": "river", "maxOffset": 1024, "segments": 64}]
                     }
                   }
                 }
@@ -191,6 +395,7 @@ public class PackRiverValidatorTest {
                   "rivers": {
                     "enabled": true,
                     "terrain": {
+                      "worms": [{"id": "river"}],
                       "maxChannelWidth": 0,
                       "maxBankWidth": -1,
                       "maxDepth": 513
@@ -214,6 +419,7 @@ public class PackRiverValidatorTest {
                   "rivers": {
                     "enabled": true,
                     "terrain": {
+                      "worms": [{"id": "river"}],
                       "maxChannelWidth": 2048,
                       "tunnelMouthBlend": 16
                     }
@@ -234,6 +440,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "biomes": {
                       "channel": ["biome", "missing"],
                       "bank": ["biome"]
@@ -257,6 +464,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "biomes": {
                       "channel": ["biome"],
                       "bank": ["biome"]
@@ -292,7 +500,10 @@ public class PackRiverValidatorTest {
         File pack = pack("""
                 {
                   "regions": ["region"],
-                  "rivers": {"enabled": true}
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]}
+                  }
                 }
                 """);
         write(pack, "regions/region.json", """
@@ -326,7 +537,10 @@ public class PackRiverValidatorTest {
         File pack = pack("""
                 {
                   "regions": ["region"],
-                  "rivers": {"enabled": true}
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]}
+                  }
                 }
                 """);
         write(pack, "regions/region.json", """
@@ -352,6 +566,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "caves": {
                       "mode": "GENERATE_GROTTO",
                       "throatRadius": 4,
@@ -383,6 +598,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "caves": {
                       "mode": "FLOOD_CLOSED_COMPONENT",
                       "maximumPerReach": 0,
@@ -406,7 +622,10 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
-                    "terrain": {"terminalMode": "SINKHOLE_GROTTO"},
+                    "terrain": {
+                      "worms": [{"id": "river"}],
+                      "terminalMode": "SINKHOLE_GROTTO"
+                    },
                     "caves": {"mode": "SEALED"}
                   }
                 }
@@ -424,7 +643,10 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
-                    "terrain": {"terminalMode": "SINKHOLE_GROTTO"},
+                    "terrain": {
+                      "worms": [{"id": "river"}],
+                      "terminalMode": "SINKHOLE_GROTTO"
+                    },
                     "caves": {
                       "mode": "GENERATE_GROTTO",
                       "maximumPerReach": 0
@@ -446,7 +668,10 @@ public class PackRiverValidatorTest {
                   "carvingEnabled": false,
                   "rivers": {
                     "enabled": true,
-                    "terrain": {"terminalMode": "SINKHOLE_GROTTO"},
+                    "terrain": {
+                      "worms": [{"id": "river"}],
+                      "terminalMode": "SINKHOLE_GROTTO"
+                    },
                     "caves": {"mode": "GENERATE_GROTTO"}
                   }
                 }
@@ -464,7 +689,10 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
-                    "terrain": {"terminalMode": "SINKHOLE_GROTTO"},
+                    "terrain": {
+                      "worms": [{"id": "river"}],
+                      "terminalMode": "SINKHOLE_GROTTO"
+                    },
                     "caves": {
                       "mode": "FLOOD_CLOSED_COMPONENT",
                       "fallback": "SEALED",
@@ -490,6 +718,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "caves": {"mode": "SEALED"}
                   }
                 }
@@ -514,6 +743,7 @@ public class PackRiverValidatorTest {
                   "carvingEnabled": false,
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "caves": {"mode": "GENERATE_GROTTO"}
                   }
                 }
@@ -545,6 +775,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "topology": {
                       "routingStyle": {"expression": "route"}
                     }
@@ -587,6 +818,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "topology": {
                       "routingStyle": {"expression": "route"}
                     }
@@ -618,6 +850,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "topology": {
                       "routingStyle": "snippet/style/first"
                     }
@@ -639,6 +872,7 @@ public class PackRiverValidatorTest {
                   "regions": ["region"],
                   "rivers": {
                     "enabled": true,
+                    "terrain": {"worms": [{"id": "river"}]},
                     "topology": {
                       "routingStyle": {"expression": "route"}
                     }
@@ -677,6 +911,50 @@ public class PackRiverValidatorTest {
         return pack;
     }
 
+    private File packWithWorms(String worms) throws Exception {
+        return pack("""
+                {
+                  "regions": ["region"],
+                  "rivers": {
+                    "enabled": true,
+                    "terrain": {"worms": %s}
+                  }
+                }
+                """.formatted(worms));
+    }
+
+    private String wormHierarchy(int rootCount, int childrenPerRoot) {
+        StringBuilder hierarchy = new StringBuilder("[");
+        int seed = 1;
+        for (int rootIndex = 0; rootIndex < rootCount; rootIndex++) {
+            if (rootIndex > 0) {
+                hierarchy.append(',');
+            }
+            hierarchy.append("{\"id\":\"root_")
+                    .append(rootIndex)
+                    .append("\",\"seed\":")
+                    .append(seed++);
+            if (childrenPerRoot > 0) {
+                hierarchy.append(",\"children\":[");
+                for (int childIndex = 0; childIndex < childrenPerRoot; childIndex++) {
+                    if (childIndex > 0) {
+                        hierarchy.append(',');
+                    }
+                    hierarchy.append("{\"id\":\"child_")
+                            .append(rootIndex)
+                            .append('_')
+                            .append(childIndex)
+                            .append("\",\"seed\":")
+                            .append(seed++)
+                            .append('}');
+                }
+                hierarchy.append(']');
+            }
+            hierarchy.append('}');
+        }
+        return hierarchy.append(']').toString();
+    }
+
     private void assertContains(List<String> messages, String fragment) {
         assertTrue(messages.toString(), contains(messages, fragment));
     }

core/src/test/java/art/arcane/iris/core/project/IrisRiverSchemaTest.java

@@ -30,7 +30,10 @@ public class IrisRiverSchemaTest {
         JSONObject properties = schema.getJSONObject("properties");
         JSONObject topology = referencedProperties(definitions, properties.getJSONObject("topology"));
         JSONObject source = referencedProperties(definitions, topology.getJSONObject("source"));
-        JSONObject terrain = referencedProperties(definitions, properties.getJSONObject("terrain"));
+        JSONObject terrainDefinition = referencedDefinition(definitions, properties.getJSONObject("terrain"));
+        JSONObject terrain = terrainDefinition.getJSONObject("properties");
+        JSONObject worms = terrain.getJSONObject("worms");
+        JSONObject worm = referencedProperties(definitions, worms.getJSONObject("items"));
         JSONObject water = referencedProperties(definitions, properties.getJSONObject("water"));
         JSONObject biomes = referencedProperties(definitions, properties.getJSONObject("biomes"));
 
@@ -46,6 +49,29 @@ public class IrisRiverSchemaTest {
         assertEquals(2048D, terrain.getJSONObject("maxChannelWidth").getDouble("maximum"), 0D);
         assertEquals(0D, terrain.getJSONObject("maxBankWidth").getDouble("minimum"), 0D);
         assertEquals(512D, terrain.getJSONObject("maxDepth").getDouble("maximum"), 0D);
+        assertTrue(arrayContains(terrainDefinition.getJSONArray("required"), "worms"));
+        assertEquals("array", worms.getString("type"));
+        assertEquals(1, worms.getInt("minItems"));
+        assertEquals(0.000001D, worm.getJSONObject("weight").getDouble("minimum"), 0D);
+        assertEquals(16384D, worm.getJSONObject("wavelength").getDouble("maximum"), 0D);
+        assertEquals(1D, worm.getJSONObject("tortuosity").getDouble("maximum"), 0D);
+        assertEquals(1024D, worm.getJSONObject("maxOffset").getDouble("maximum"), 0D);
+        assertEquals(64, worm.getJSONObject("segments").getInt("maximum"));
+        assertEquals(0.125D, worm.getJSONObject("widthMultiplier").getDouble("minimum"), 0D);
+        assertEquals(8D, worm.getJSONObject("bankMultiplier").getDouble("maximum"), 0D);
+        assertEquals(8D, worm.getJSONObject("depthMultiplier").getDouble("maximum"), 0D);
+        assertEquals(32D, worm.getJSONObject("bodyWavelength").getDouble("minimum"), 0D);
+        assertEquals(16384D, worm.getJSONObject("bodyDetailWavelength").getDouble("maximum"), 0D);
+        assertEquals(0.875D, worm.getJSONObject("widthVariation").getDouble("maximum"), 0D);
+        assertEquals(0.875D, worm.getJSONObject("bankVariation").getDouble("maximum"), 0D);
+        assertEquals(0.875D, worm.getJSONObject("depthVariation").getDouble("maximum"), 0D);
+        assertEquals(0.875D, worm.getJSONObject("roofVariation").getDouble("maximum"), 0D);
+        assertEquals(8, worm.getJSONObject("branchCap").getInt("maximum"));
+        assertEquals(1D, worm.getJSONObject("branchDecay").getDouble("maximum"), 0D);
+        assertEquals(8D, worm.getJSONObject("confluenceMultiplier").getDouble("maximum"), 0D);
+        assertEquals(1D, worm.getJSONObject("childChance").getDouble("maximum"), 0D);
+        assertEquals(1D, worm.getJSONObject("branchChildChance").getDouble("maximum"), 0D);
+        assertEquals("array", worm.getJSONObject("children").getString("type"));
         assertEquals(List.of("SEA_LEVEL", "TERRACED"), enumValues(definitions, water.getJSONObject("mode")));
         assertEquals("array", biomes.getJSONObject("channel").getString("type"));
         assertEquals("#/definitions/erzbiomes",
@@ -87,8 +113,21 @@ public class IrisRiverSchemaTest {
     }
 
     private static JSONObject referencedProperties(JSONObject definitions, JSONObject reference) {
+        return referencedDefinition(definitions, reference).getJSONObject("properties");
+    }
+
+    private static JSONObject referencedDefinition(JSONObject definitions, JSONObject reference) {
         String key = reference.getString("$ref").substring("#/definitions/".length());
-        return definitions.getJSONObject(key).getJSONObject("properties");
+        return definitions.getJSONObject(key);
+    }
+
+    private static boolean arrayContains(JSONArray values, String expected) {
+        for (int index = 0; index < values.length(); index++) {
+            if (expected.equals(values.getString(index))) {
+                return true;
+            }
+        }
+        return false;
     }
 
     private static List<String> enumValues(JSONObject definitions, JSONObject reference) {

core/src/test/java/art/arcane/iris/engine/object/IrisRiverConfigurationTest.java

@@ -36,6 +36,7 @@ public class IrisRiverConfigurationTest {
         assertEquals(10D, dimension.getRivers().getTerrain().getMaxChannelWidth(), 0D);
         assertEquals(4D, dimension.getRivers().getTerrain().getMaxBankWidth(), 0D);
         assertEquals(10D, dimension.getRivers().getTerrain().getMaxDepth(), 0D);
+        assertTrue(dimension.getRivers().getTerrain().getWorms().isEmpty());
         assertEquals(IrisRiverCaveMode.SEALED, dimension.getRivers().getCaves().getMode());
         assertEquals(IrisRiverCaveFallback.SEALED, dimension.getRivers().getCaves().getFallback());
         assertEquals(IrisRiverExistingFluidPolicy.REJECT,
@@ -65,6 +66,27 @@ public class IrisRiverConfigurationTest {
                       "maxBankWidth": 2.5,
                       "maxDepth": 8,
                       "maxIncision": 36,
+                      "worms": [
+                        {
+                          "seed": 73,
+                          "weight": 2.5,
+                          "wavelength": 1536,
+                          "detailWavelength": 192,
+                          "tortuosity": 0.65,
+                          "detailTortuosity": 0.2,
+                          "maxOffset": 420,
+                          "segments": 56,
+                          "widthMultiplier": 1.4,
+                          "bankMultiplier": 1.2,
+                          "depthMultiplier": 0.8,
+                          "bodyWavelength": 704,
+                          "bodyDetailWavelength": 88,
+                          "widthVariation": 0.75,
+                          "bankVariation": 0.65,
+                          "depthVariation": 0.55,
+                          "roofVariation": 0.45
+                        }
+                      ],
                       "terminalMode": "SUPPRESS"
                     },
                     "water": {"mode": "TERRACED", "poolLength": 80},
@@ -111,6 +133,24 @@ public class IrisRiverConfigurationTest {
         assertEquals(2.5D, dimension.getRivers().getTerrain().getMaxBankWidth(), 0D);
         assertEquals(8D, dimension.getRivers().getTerrain().getMaxDepth(), 0D);
         assertEquals(36, dimension.getRivers().getTerrain().getMaxIncision());
+        IrisRiverWorm worm = dimension.getRivers().getTerrain().getWorms().get(0);
+        assertEquals(73L, worm.getSeed());
+        assertEquals(2.5D, worm.getWeight(), 0D);
+        assertEquals(1536D, worm.getWavelength(), 0D);
+        assertEquals(192D, worm.getDetailWavelength(), 0D);
+        assertEquals(0.65D, worm.getTortuosity(), 0D);
+        assertEquals(0.2D, worm.getDetailTortuosity(), 0D);
+        assertEquals(420D, worm.getMaxOffset(), 0D);
+        assertEquals(56, worm.getSegments());
+        assertEquals(1.4D, worm.getWidthMultiplier(), 0D);
+        assertEquals(1.2D, worm.getBankMultiplier(), 0D);
+        assertEquals(0.8D, worm.getDepthMultiplier(), 0D);
+        assertEquals(704D, worm.getBodyWavelength(), 0D);
+        assertEquals(88D, worm.getBodyDetailWavelength(), 0D);
+        assertEquals(0.75D, worm.getWidthVariation(), 0D);
+        assertEquals(0.65D, worm.getBankVariation(), 0D);
+        assertEquals(0.55D, worm.getDepthVariation(), 0D);
+        assertEquals(0.45D, worm.getRoofVariation(), 0D);
         assertEquals(IrisRiverTerminalMode.SUPPRESS,
                 dimension.getRivers().getTerrain().getTerminalMode());
         assertEquals(IrisRiverWaterMode.TERRACED, dimension.getRivers().getWater().getMode());
@@ -145,7 +185,11 @@ public class IrisRiverConfigurationTest {
                 .setFloodedCaveBiomes(new KList<>("biome-grotto"));
         IrisDimension dimension = new IrisDimension()
                 .setRegions(new KList<>("region"))
-                .setRivers(new IrisRiverNetwork().setEnabled(true).setBiomes(dimensionBiomes));
+                .setRivers(new IrisRiverNetwork()
+                        .setEnabled(true)
+                        .setTerrain(new IrisRiverTerrain()
+                                .setWorms(new KList<>(new IrisRiverWorm())))
+                        .setBiomes(dimensionBiomes));
         IrisRegion region = new IrisRegion()
                 .setLandBiomes(new KList<>("natural"))
                 .setRiverOverride(regionOverride);

core/src/test/java/art/arcane/iris/engine/river/RiverNetworkTest.java

@@ -21,8 +21,6 @@ import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
 public class RiverNetworkTest {
-    private static final double TWO_PI_FOR_TESTS = StrictMath.PI * 2D;
-
     @Test
     public void mapsNegativeWorldCoordinatesWithFloorDivision() {
         RiverNetwork network = new RiverNetwork(options(1L).build());
@@ -164,12 +162,25 @@ public class RiverNetworkTest {
     }
 
     @Test
-    public void recursiveBranchesApplyTheChildSoftCapAtEveryNode() {
+    public void recursiveBranchesApplyTheProfileChildSoftCapAtEveryNode() {
+        RiverWorm constrained = wormProfile(
+                "constrained",
+                720L,
+                6,
+                1D,
+                1D,
+                1D,
+                4,
+                0D,
+                1D,
+                0D,
+                0D,
+                List.of()
+        );
         RiverNetwork network = new RiverNetwork(options(720L)
                 .requireOcean(false)
                 .routingBasinCells(16)
-                .branchSoftCap(4)
-                .branchChildShrinkFactor(0D)
+                .worms(List.of(constrained))
                 .build());
         RiverTerrainSampler terrain = flatTerrain(false);
         HashMap<RiverNodeId, Integer> incoming = new HashMap<>();
@@ -188,36 +199,29 @@ public class RiverNetworkTest {
     }
 
     @Test
-    public void candidateRankingAndTracingDoNotMaterializeMeanderGeometry() {
-        RiverNetwork network = new RiverNetwork(options(75L)
+    public void candidateRankingAndTracingAreIndependentOfWormGeometry() {
+        RiverNetwork straightNetwork = new RiverNetwork(options(75L)
                 .requireOcean(false)
-                .meanderSubdivisions(32)
+                .worms(List.of(worm(1L, 0D, 0D, 0D, 1)))
+                .build());
+        RiverNetwork windingNetwork = new RiverNetwork(options(75L)
+                .requireOcean(false)
+                .worms(List.of(worm(2L, 0.8D, 0.2D, 32D, 32)))
                 .build());
-        int[] meanderSamples = new int[1];
         RiverTerrainSampler terrain = new TestTerrain(false) {
             @Override
             public double reachRoutingCost(RiverRoutingContext context) {
                 return context.midpointX() + context.midpointZ();
             }
-
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                meanderSamples[0]++;
-                return 0D;
-            }
         };
+        RiverNodeId source = new RiverNodeId(0L, 0L);
 
-        assertFalse(network.downstreamCandidates(new RiverNodeId(0L, 0L), terrain).isEmpty());
-        assertEquals(0, meanderSamples[0]);
-        assertFalse(network.trace(new RiverNodeId(0L, 0L), terrain).edges().isEmpty());
-        assertEquals(0, meanderSamples[0]);
-
-        RiverTile tile = network.buildTile(0, 0, terrain);
-
-        assertFalse(tile.reaches().isEmpty());
-        assertTrue(meanderSamples[0] > 0);
-        assertEquals(0, meanderSamples[0] % 12);
-        assertTrue(meanderSamples[0] / 12 <= 256);
+        assertFalse(straightNetwork.downstreamCandidates(source, terrain).isEmpty());
+        assertEquals(
+                straightNetwork.downstreamCandidates(source, terrain),
+                windingNetwork.downstreamCandidates(source, terrain)
+        );
+        assertEquals(straightNetwork.trace(source, terrain), windingNetwork.trace(source, terrain));
     }
 
     @Test
@@ -616,10 +620,10 @@ public class RiverNetworkTest {
         );
 
         assertEquals(List.of(
-                3050685048971830506L,
-                -3861364772874819248L,
-                -8770785170128501517L,
-                6698607697170340377L
+                973031325888677478L,
+                8932177974453767311L,
+                -5189009084208004632L,
+                6374264141259432071L
         ), actual);
     }
 
@@ -659,9 +663,20 @@ public class RiverNetworkTest {
                 .channelWidth(512D)
                 .maxChannelWidth(512D)
                 .bankWidth(0D)
-                .branchChildShrinkFactor(1D)
-                .meanderStrength(0D)
-                .meanderSubdivisions(1)
+                .worms(List.of(wormProfile(
+                        "straight",
+                        1L,
+                        1,
+                        1D,
+                        1D,
+                        1D,
+                        8,
+                        1D,
+                        1D,
+                        0D,
+                        0D,
+                        List.of()
+                )))
                 .build());
         RiverTerrainSampler terrain = new TestTerrain(false) {
             @Override
@@ -787,9 +802,9 @@ public class RiverNetworkTest {
                 1,
                 1,
                 10.0,
-                RiverWidthProfile.constant(10.0),
                 5.0,
                 3.0,
+                RiverBodyProfile.constant(10.0, 5.0, 3.0),
                 false,
                 true,
                 new RiverPolyline(new double[]{0.0, 100.0}, new double[]{0.0, 0.0})
@@ -867,14 +882,9 @@ public class RiverNetworkTest {
                 .maxChannelWidth(10D)
                 .maxBankWidth(3D)
                 .maxDepth(6D)
-                .meanderStrength(0D)
+                .worms(List.of(worm(1L, 0D, 0D, 0D, 1)))
                 .build());
         RiverTerrainSampler styled = new TestTerrain(false) {
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                return 0.0;
-            }
-
             @Override
             public double channelWidth(RiverRoutingContext context, double fallback) {
                 return 20.0;
@@ -906,12 +916,15 @@ public class RiverNetworkTest {
     }
 
     @Test
-    public void channelWidthVariesInsideOneReachAndRemainsSpatiallyQueryable() {
+    public void bodyAnatomyVariesInsideOneReachAndRemainsSpatiallyQueryable() {
         RiverNode from = node(0L, 0L, 0D, 0D);
         RiverNode to = node(1L, 0L, 100D, 0D);
-        RiverWidthProfile profile = new RiverWidthProfile(
+        RiverBodyProfile profile = new RiverBodyProfile(
                 new double[]{0D, 0.5D, 1D},
-                new double[]{1D, 7D, 1D}
+                new double[]{1D, 7D, 1D},
+                new double[]{1D, 9D, 1D},
+                new double[]{2D, 8D, 2D},
+                new double[]{1D, 0.35D, 1D}
         );
         RiverReach reach = new RiverReach(
                 RiverEdgeId.of(from.id(), to.id()),
@@ -921,31 +934,100 @@ public class RiverNetworkTest {
                 1,
                 1,
                 7D,
+                9D,
+                8D,
                 profile,
-                0D,
-                3D,
                 false,
                 false,
                 new RiverPolyline(new double[]{0D, 100D}, new double[]{0D, 0D})
         );
         RiverTile tile = new RiverTile(0, 0, 0, -16, 128, 32, List.of(reach));
 
-        RiverSample narrow = tile.sample(10D, 2D);
-        RiverSample wide = tile.sample(50D, 2D);
+        RiverSample narrow = tile.sample(10D, 7D);
+        RiverSample swollen = tile.sample(50D, 7D);
 
         assertFalse(narrow.present());
-        assertTrue(wide.present());
-        assertEquals(7D, wide.width(), 0D);
-        assertEquals(RiverSection.CHANNEL, wide.section());
+        assertTrue(swollen.present());
+        assertEquals(7D, swollen.width(), 0D);
+        assertEquals(9D, swollen.bankWidth(), 0D);
+        assertEquals(8D, swollen.depth(), 0D);
+        assertEquals(0.35D, reach.roofScaleAt(swollen.alongReach()), 0.0000001D);
+        assertEquals(RiverSection.BANK, swollen.section());
+    }
+
+    @Test
+    public void perlinWormBodyAnatomyVariesAllDimensionsDeterministically() {
+        RiverWorm anatomy = wormProfile(
+                "anatomy",
+                917L,
+                24,
+                1D,
+                1D,
+                1D,
+                64D,
+                32D,
+                0.875D,
+                0.875D,
+                0.875D,
+                0.875D,
+                4,
+                0.35D,
+                1D,
+                0D,
+                0D,
+                List.of()
+        );
+        RiverNetwork network = new RiverNetwork(options(917L)
+                .requireOcean(false)
+                .maxChannelWidth(64D)
+                .maxBankWidth(64D)
+                .maxDepth(64D)
+                .maximumReachRadius(96D)
+                .worms(List.of(anatomy))
+                .build());
+        RiverTerrainSampler terrain = flatTerrain(false);
+
+        RiverTile first = network.buildTile(0, 0, terrain);
+        RiverTile second = network.buildTile(0, 0, terrain);
+
+        assertFalse(first.reaches().isEmpty());
+        assertEquals(digest(first), digest(second));
+        double minimumWidth = Double.POSITIVE_INFINITY;
+        double maximumWidth = 0D;
+        double minimumBank = Double.POSITIVE_INFINITY;
+        double maximumBank = 0D;
+        double minimumDepth = Double.POSITIVE_INFINITY;
+        double maximumDepth = 0D;
+        double minimumRoof = Double.POSITIVE_INFINITY;
+        double maximumRoof = 0D;
+        for (RiverReach reach : first.reaches()) {
+            for (int index = 0; index < reach.bodyProfile().size(); index++) {
+                minimumWidth = StrictMath.min(minimumWidth, reach.bodyProfile().widthAtIndex(index));
+                maximumWidth = StrictMath.max(maximumWidth, reach.bodyProfile().widthAtIndex(index));
+                minimumBank = StrictMath.min(minimumBank, reach.bodyProfile().bankWidthAtIndex(index));
+                maximumBank = StrictMath.max(maximumBank, reach.bodyProfile().bankWidthAtIndex(index));
+                minimumDepth = StrictMath.min(minimumDepth, reach.bodyProfile().depthAtIndex(index));
+                maximumDepth = StrictMath.max(maximumDepth, reach.bodyProfile().depthAtIndex(index));
+                minimumRoof = StrictMath.min(minimumRoof, reach.bodyProfile().roofScaleAtIndex(index));
+                maximumRoof = StrictMath.max(maximumRoof, reach.bodyProfile().roofScaleAtIndex(index));
+            }
+        }
+        assertTrue(maximumWidth - minimumWidth > 2D);
+        assertTrue(maximumBank - minimumBank > 1.5D);
+        assertTrue(maximumDepth - minimumDepth > 0.75D);
+        assertTrue(maximumRoof - minimumRoof > 0.1D);
     }
 
     @Test
     public void foldedReachSamplingFindsFartherCoveringWidthEnvelope() {
         RiverNode from = node(0L, 0L, 0D, 0D);
         RiverNode to = node(1L, 0L, 0D, 10D);
-        RiverWidthProfile profile = new RiverWidthProfile(
+        RiverBodyProfile profile = new RiverBodyProfile(
                 new double[]{0D, 0.48D, 0.53D, 1D},
-                new double[]{1D, 1D, 18D, 18D}
+                new double[]{1D, 1D, 18D, 18D},
+                new double[]{0D, 0D, 0D, 0D},
+                new double[]{3D, 3D, 3D, 3D},
+                new double[]{1D, 1D, 1D, 1D}
         );
         RiverReach reach = new RiverReach(
                 RiverEdgeId.of(from.id(), to.id()),
@@ -955,9 +1037,9 @@ public class RiverNetworkTest {
                 1,
                 1,
                 18D,
-                profile,
                 0D,
                 3D,
+                profile,
                 false,
                 false,
                 new RiverPolyline(
@@ -978,15 +1060,12 @@ public class RiverNetworkTest {
     }
 
     @Test
-    public void reachFeasibilityReceivesTheFinalPinnedMeanderPolyline() {
-        RiverNetwork network = new RiverNetwork(options(62L).meanderStrength(20D).build());
-        boolean[] observedMeander = new boolean[1];
+    public void reachFeasibilityReceivesTheFinalPinnedWormPolyline() {
+        RiverNetwork network = new RiverNetwork(options(62L)
+                .worms(List.of(worm(62L, 0.8D, 0.2D, 20D, 32)))
+                .build());
+        boolean[] observedWorm = new boolean[1];
         RiverTerrainSampler terrain = new TestTerrain(false) {
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                return 1D;
-            }
-
             @Override
             public boolean allowsReach(RiverRoutingContext context) {
                 RiverPolyline polyline = context.polyline();
@@ -996,7 +1075,7 @@ public class RiverNetworkTest {
                     double pointX = polyline.x(point) - context.from().x();
                     double pointZ = polyline.z(point) - context.from().z();
                     if (StrictMath.abs(pointX * deltaZ - pointZ * deltaX) > 0.000001D) {
-                        observedMeander[0] = true;
+                        observedWorm[0] = true;
                         return false;
                     }
                 }
@@ -1006,76 +1085,66 @@ public class RiverNetworkTest {
 
         RiverNode downstream = network.downstream(new RiverNodeId(0L, 0L), terrain);
 
-        assertTrue(observedMeander[0]);
+        assertTrue(observedWorm[0]);
         assertEquals(null, downstream);
     }
 
     @Test
-    public void irisNoiseChangesTheSelectedPersonalityWithoutBreakingItsEnvelope() {
-        double meanderStrength = 20D;
-        RiverNetwork network = new RiverNetwork(options(63L)
+    public void wormSeedChangesDeterministicGeometryWithoutBreakingItsEnvelope() {
+        double maximumOffset = 20D;
+        RiverNetwork firstNetwork = new RiverNetwork(options(63L)
                 .siteJitter(0D)
                 .requireOcean(false)
-                .meanderStrength(meanderStrength)
-                .meanderSubdivisions(32)
+                .worms(List.of(worm(101L, 0.8D, 0.2D, maximumOffset, 32)))
                 .build());
-        RiverTerrainSampler quietTerrain = new TestTerrain(false) {
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                return 0D;
-            }
-        };
-        RiverTerrainSampler noisyTerrain = new TestTerrain(false) {
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                return StrictMath.sin(context.normalizedPosition() * StrictMath.PI * 7D);
-            }
-        };
+        RiverNetwork secondNetwork = new RiverNetwork(options(63L)
+                .siteJitter(0D)
+                .requireOcean(false)
+                .worms(List.of(worm(202L, 0.8D, 0.2D, maximumOffset, 32)))
+                .build());
+        RiverTerrainSampler terrain = new TestTerrain(false);
 
-        RiverReach quietReach = network.buildTile(0, 0, quietTerrain).reaches().getFirst();
-        RiverReach noisyReach = network.buildTile(0, 0, noisyTerrain).reaches().getFirst();
-        assertEquals(quietReach.id(), noisyReach.id());
-        RiverPolyline quietPolyline = quietReach.polyline();
-        RiverPolyline noisyPolyline = noisyReach.polyline();
-        double deltaX = noisyReach.to().x() - noisyReach.from().x();
-        double deltaZ = noisyReach.to().z() - noisyReach.from().z();
-        double chordLength = StrictMath.hypot(deltaX, deltaZ);
-        boolean changed = false;
-        for (int point = 1; point < noisyPolyline.size() - 1; point++) {
-            double pointX = noisyPolyline.x(point) - noisyReach.from().x();
-            double pointZ = noisyPolyline.z(point) - noisyReach.from().z();
-            double signedOffset = (pointX * deltaZ - pointZ * deltaX) / chordLength;
-            if (Double.doubleToLongBits(noisyPolyline.x(point)) != Double.doubleToLongBits(quietPolyline.x(point))
-                    || Double.doubleToLongBits(noisyPolyline.z(point))
-                    != Double.doubleToLongBits(quietPolyline.z(point))) {
-                changed = true;
-            }
-            assertTrue(StrictMath.abs(signedOffset) <= meanderStrength + 0.0000001D);
-        }
+        RiverReach firstReach = firstNetwork.buildTile(0, 0, terrain).reaches().getFirst();
+        RiverReach repeatedReach = firstNetwork.buildTile(0, 0, terrain).reaches().getFirst();
+        RiverReach secondReach = secondNetwork.buildTile(0, 0, terrain).reaches().getFirst();
 
-        assertTrue(changed);
-        assertEquals(noisyReach.from().x(), noisyPolyline.x(0), 0D);
-        assertEquals(noisyReach.from().z(), noisyPolyline.z(0), 0D);
-        int last = noisyPolyline.size() - 1;
-        assertEquals(noisyReach.to().x(), noisyPolyline.x(last), 0D);
-        assertEquals(noisyReach.to().z(), noisyPolyline.z(last), 0D);
+        assertReachEquals(firstReach, repeatedReach);
+        assertEquals(firstReach.id(), secondReach.id());
+        assertTrue(polylinesDiffer(firstReach.polyline(), secondReach.polyline()));
+        assertWormBounds(firstReach, maximumOffset);
+        assertWormBounds(secondReach, maximumOffset);
     }
 
     @Test
-    public void reachesSpanBroadAsymmetricCompoundAndRestlessShapeFamilies() {
-        double meanderStrength = 20D;
+    public void weightedWormProfilesSelectDistinctConfigurableVariants() {
+        RiverWorm gentle = new RiverWorm(
+                "gentle", 301L, 1D, 1024D, 256D, 0.2D, 0.05D, 10D, 8, 0.5D, 0.5D, 0.5D,
+                512D, 128D, 0D, 0D, 0D, 0D,
+                4, 0.35D, 1D, 0D, 0D, List.of()
+        );
+        RiverWorm winding = new RiverWorm(
+                "winding", 302L, 1D, 512D, 128D, 0.55D, 0.15D, 20D, 16, 1D, 1D, 1D,
+                512D, 128D, 0D, 0D, 0D, 0D,
+                4, 0.35D, 1D, 0D, 0D, List.of()
+        );
+        RiverWorm restless = new RiverWorm(
+                "restless", 303L, 1D, 192D, 48D, 0.9D, 0.35D, 30D, 32, 2D, 2D, 2D,
+                512D, 128D, 0D, 0D, 0D, 0D,
+                4, 0.35D, 1D, 0D, 0D, List.of()
+        );
         RiverNetwork network = new RiverNetwork(options(64L)
                 .siteJitter(0D)
+                .routingBasinCells(8)
                 .requireOcean(false)
-                .meanderStrength(meanderStrength)
-                .meanderSubdivisions(48)
+                .maxChannelWidth(32D)
+                .maxBankWidth(32D)
+                .maxDepth(32D)
+                .orderWidthFactor(0D)
+                .orderDepthFactor(0D)
+                .maximumReachRadius(32D)
+                .worms(List.of(gentle, winding, restless))
                 .build());
-        RiverTerrainSampler terrain = new TestTerrain(false) {
-            @Override
-            public double meanderNoise(RiverMeanderContext context) {
-                return 0D;
-            }
-        };
+        RiverTerrainSampler terrain = new TestTerrain(false);
 
         HashMap<RiverEdgeId, RiverReach> uniqueReaches = new HashMap<>();
         for (int tileX = -2; tileX <= 2; tileX++) {
@@ -1085,39 +1154,217 @@ public class RiverNetworkTest {
                 }
             }
         }
-        ArrayList<ReachShape> shapes = new ArrayList<>(uniqueReaches.size());
+        Set<Integer> selectedPointCounts = new HashSet<>();
+        HashMap<Integer, Double> maximumDisplacementRatios = new HashMap<>();
         for (RiverReach reach : uniqueReaches.values()) {
-            shapes.add(shapeOf(reach, meanderStrength));
-        }
-        double minimumAmplitude = shapes.stream()
-                .mapToDouble(ReachShape::amplitudeRatio)
-                .min()
-                .orElseThrow();
-        double maximumAmplitude = shapes.stream()
-                .mapToDouble(ReachShape::amplitudeRatio)
-                .max()
-                .orElseThrow();
-        HashSet<Integer> dominantBands = new HashSet<>();
-        HashSet<String> signatures = new HashSet<>();
-        for (ReachShape shape : shapes) {
-            dominantBands.add(shape.dominantBand());
-            signatures.add(
-                    StrictMath.min(6, shape.crossings()) + ":"
-                            + (int) StrictMath.floor(shape.centroid() * 5D) + ":"
-                            + (int) StrictMath.floor(shape.amplitudeRatio() * 5D) + ":"
-                            + shape.dominantBand()
+            int pointCount = reach.polyline().size();
+            selectedPointCounts.add(pointCount);
+            RiverWorm selected = switch (pointCount) {
+                case 9 -> gentle;
+                case 17 -> winding;
+                case 33 -> restless;
+                default -> throw new AssertionError("Unexpected worm point count " + pointCount);
+            };
+            assertEquals(8D * selected.widthMultiplier(), reach.width(), 0.0000001D);
+            assertEquals(6D * selected.bankMultiplier(), reach.bankWidth(), 0.0000001D);
+            assertEquals(3D * selected.depthMultiplier(), reach.depth(), 0.0000001D);
+            assertWormBounds(reach, selected.maxOffset());
+            maximumDisplacementRatios.merge(
+                    pointCount,
+                    maximumWormDisplacement(reach) / selected.maxOffset(),
+                    StrictMath::max
             );
         }
-        String diagnostics = shapes.toString();
-        assertTrue(diagnostics, shapes.size() >= 32);
-        assertTrue(diagnostics, shapes.stream().anyMatch(shape -> shape.crossings() <= 1));
-        assertTrue(diagnostics, shapes.stream().anyMatch(shape -> shape.crossings() >= 2 && shape.crossings() <= 4));
-        assertTrue(diagnostics, shapes.stream().anyMatch(shape -> shape.crossings() >= 5));
-        assertTrue(diagnostics, shapes.stream().anyMatch(shape -> shape.centroid() < 0.43D));
-        assertTrue(diagnostics, shapes.stream().anyMatch(shape -> shape.centroid() > 0.57D));
-        assertTrue(diagnostics, maximumAmplitude - minimumAmplitude >= 0.25D);
-        assertTrue(diagnostics, dominantBands.size() >= 3);
-        assertTrue(diagnostics, signatures.size() >= 8);
+        assertEquals(Set.of(9, 17, 33), selectedPointCounts);
+        assertTrue(maximumDisplacementRatios.toString(), maximumDisplacementRatios.get(9) > 0.03D);
+        assertTrue(maximumDisplacementRatios.toString(), maximumDisplacementRatios.get(17) > 0.18D);
+        assertTrue(maximumDisplacementRatios.toString(), maximumDisplacementRatios.get(33) > 0.4D);
+    }
+
+    @Test
+    public void forcedChildHierarchyControlsReachGeometryAndDimensionsDeterministically() {
+        RiverWorm child = wormProfile(
+                "child",
+                402L,
+                24,
+                2D,
+                1.5D,
+                0.5D,
+                8,
+                1D,
+                1D,
+                0D,
+                0D,
+                List.of()
+        );
+        RiverWorm root = wormProfile(
+                "root",
+                401L,
+                8,
+                0.5D,
+                0.5D,
+                0.5D,
+                8,
+                1D,
+                1D,
+                1D,
+                0D,
+                List.of(child)
+        );
+        RiverNetwork network = new RiverNetwork(options(68L)
+                .siteJitter(0D)
+                .requireOcean(false)
+                .maxChannelWidth(32D)
+                .maxBankWidth(32D)
+                .maxDepth(32D)
+                .orderWidthFactor(0D)
+                .orderDepthFactor(0D)
+                .maximumReachRadius(32D)
+                .worms(List.of(root))
+                .build());
+        RiverTerrainSampler terrain = new TestTerrain(false);
+
+        RiverTile first = network.buildTile(0, 0, terrain);
+        RiverTile second = network.buildTile(0, 0, terrain);
+
+        assertFalse(first.reaches().isEmpty());
+        assertEquals(digest(first), digest(second));
+        for (RiverReach reach : first.reaches()) {
+            assertEquals(child.segments() + 1, reach.polyline().size());
+            assertEquals(8D * child.widthMultiplier(), reach.width(), 0.0000001D);
+            assertEquals(6D * child.bankMultiplier(), reach.bankWidth(), 0.0000001D);
+            assertEquals(3D * child.depthMultiplier(), reach.depth(), 0.0000001D);
+            assertWormBounds(reach, child.maxOffset());
+        }
+    }
+
+    @Test
+    public void wormHierarchyRejectsInvalidIdsDepthAndCounts() {
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "Invalid",
+                1L,
+                8,
+                1D,
+                1D,
+                1D,
+                512D,
+                128D,
+                0D,
+                0D,
+                0D,
+                0D,
+                4,
+                0.35D,
+                1D,
+                0D,
+                0D,
+                List.of()
+        ));
+
+        RiverWorm duplicateChild = wormProfile(
+                "duplicate", 2L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 0D, 0D, List.of()
+        );
+        RiverWorm duplicateRoot = wormProfile(
+                "duplicate", 3L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 1D, 0D, List.of(duplicateChild)
+        );
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> options(10L).worms(List.of(duplicateRoot)).build()
+        );
+
+        RiverWorm tooDeep = wormProfile(
+                "depth-5", 5L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 0D, 0D, List.of()
+        );
+        for (int depth = 4; depth >= 1; depth--) {
+            tooDeep = wormProfile(
+                    "depth-" + depth,
+                    depth,
+                    8,
+                    1D,
+                    1D,
+                    1D,
+                    4,
+                    0.35D,
+                    1D,
+                    1D,
+                    0D,
+                    List.of(tooDeep)
+            );
+        }
+        RiverWorm depthRoot = tooDeep;
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> options(10L).worms(List.of(depthRoot)).build()
+        );
+
+        ArrayList<RiverWorm> roots = new ArrayList<>();
+        for (int root = 0; root < 17; root++) {
+            roots.add(wormProfile(
+                    "root-" + root, root, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 0D, 0D, List.of()
+            ));
+        }
+        assertThrows(IllegalArgumentException.class, () -> options(10L).worms(roots).build());
+
+        ArrayList<RiverWorm> branches = new ArrayList<>();
+        for (int branch = 0; branch < 8; branch++) {
+            ArrayList<RiverWorm> leaves = new ArrayList<>();
+            for (int leaf = 0; leaf < 16; leaf++) {
+                leaves.add(wormProfile(
+                        "leaf-" + branch + "-" + leaf,
+                        branch * 16L + leaf,
+                        8,
+                        1D,
+                        1D,
+                        1D,
+                        4,
+                        0.35D,
+                        1D,
+                        0D,
+                        0D,
+                        List.of()
+                ));
+            }
+            branches.add(wormProfile(
+                    "branch-" + branch,
+                    branch,
+                    8,
+                    1D,
+                    1D,
+                    1D,
+                    4,
+                    0.35D,
+                    1D,
+                    1D,
+                    0D,
+                    leaves
+            ));
+        }
+        RiverWorm oversized = wormProfile(
+                "oversized", 900L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 1D, 0D, branches
+        );
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> options(10L).worms(List.of(oversized)).build()
+        );
+    }
+
+    @Test
+    public void wormProfileRejectsInvalidBranchControls() {
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "cap", 1L, 8, 1D, 1D, 1D, 0, 0.35D, 1D, 0D, 0D, List.of()
+        ));
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "decay", 1L, 8, 1D, 1D, 1D, 4, 1.1D, 1D, 0D, 0D, List.of()
+        ));
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "confluence", 1L, 8, 1D, 1D, 1D, 4, 0.35D, 8.1D, 0D, 0D, List.of()
+        ));
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "child-chance", 1L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 1.1D, 0D, List.of()
+        ));
+        assertThrows(IllegalArgumentException.class, () -> wormProfile(
+                "sibling-chance", 1L, 8, 1D, 1D, 1D, 4, 0.35D, 1D, 0D, 1.1D, List.of()
+        ));
     }
 
     @Test
@@ -1194,8 +1441,6 @@ public class RiverNetworkTest {
         assertThrows(IllegalArgumentException.class, () -> options(10L).routingPlateauHeight(0D).build());
         assertThrows(IllegalArgumentException.class, () -> options(10L).hydraulicBaseHeight(Double.NaN).build());
         assertThrows(IllegalArgumentException.class, () -> options(10L).confluenceWeight(-1D).build());
-        assertThrows(IllegalArgumentException.class, () -> options(10L).branchSoftCap(0).build());
-        assertThrows(IllegalArgumentException.class, () -> options(10L).branchChildShrinkFactor(1.1D).build());
         assertThrows(IllegalArgumentException.class, () -> options(10L).channelWidth(-1.0).build());
         assertThrows(IllegalArgumentException.class, () -> options(10L)
                 .tileCells(1)
@@ -1255,8 +1500,7 @@ public class RiverNetworkTest {
                         .siteJitter(0.49D)
                         .maxRouteReaches(256)
                         .maximumReachRadius(pathologicalRadius)
-                        .meanderStrength(1024D)
-                        .meanderSubdivisions(64)
+                        .worms(List.of(worm(1L, 1D, 1D, 1024D, 64)))
                         .build()
         );
         assertTrue(failure.getMessage(), failure.getMessage().contains("source window"));
@@ -1278,8 +1522,126 @@ public class RiverNetworkTest {
                 .channelWidth(8.0)
                 .bankWidth(6.0)
                 .depth(3.0)
-                .meanderStrength(12.0)
-                .meanderSubdivisions(6);
+                .worms(List.of(worm(1L, 0.5D, 0.15D, 12D, 6)));
+    }
+
+    private static RiverWorm worm(
+            long seed,
+            double tortuosity,
+            double detailTortuosity,
+            double maximumOffset,
+            int segments
+    ) {
+        return new RiverWorm(
+                "worm-" + Long.toUnsignedString(seed),
+                seed,
+                1D,
+                1024D,
+                256D,
+                tortuosity,
+                detailTortuosity,
+                maximumOffset,
+                segments,
+                1D,
+                1D,
+                1D,
+                512D,
+                128D,
+                0D,
+                0D,
+                0D,
+                0D,
+                4,
+                0.35D,
+                1D,
+                0D,
+                0D,
+                List.of()
+        );
+    }
+
+    private static RiverWorm wormProfile(
+            String id,
+            long seed,
+            int segments,
+            double widthMultiplier,
+            double bankMultiplier,
+            double depthMultiplier,
+            int branchCap,
+            double branchDecay,
+            double confluenceMultiplier,
+            double childChance,
+            double branchChildChance,
+            List<RiverWorm> children
+    ) {
+        return wormProfile(
+                id,
+                seed,
+                segments,
+                widthMultiplier,
+                bankMultiplier,
+                depthMultiplier,
+                512D,
+                128D,
+                0D,
+                0D,
+                0D,
+                0D,
+                branchCap,
+                branchDecay,
+                confluenceMultiplier,
+                childChance,
+                branchChildChance,
+                children
+        );
+    }
+
+    private static RiverWorm wormProfile(
+            String id,
+            long seed,
+            int segments,
+            double widthMultiplier,
+            double bankMultiplier,
+            double depthMultiplier,
+            double bodyWavelength,
+            double bodyDetailWavelength,
+            double widthVariation,
+            double bankVariation,
+            double depthVariation,
+            double roofVariation,
+            int branchCap,
+            double branchDecay,
+            double confluenceMultiplier,
+            double childChance,
+            double branchChildChance,
+            List<RiverWorm> children
+    ) {
+        return new RiverWorm(
+                id,
+                seed,
+                1D,
+                256D,
+                64D,
+                0.7D,
+                0.2D,
+                32D,
+                segments,
+                widthMultiplier,
+                bankMultiplier,
+                depthMultiplier,
+                bodyWavelength,
+                bodyDetailWavelength,
+                widthVariation,
+                bankVariation,
+                depthVariation,
+                roofVariation,
+                branchCap,
+                branchDecay,
+                confluenceMultiplier,
+                childChance,
+                branchChildChance,
+                children
+        );
     }
 
     private static RiverNode node(long cellX, long cellZ, double x, double z) {
@@ -1305,9 +1667,9 @@ public class RiverNetworkTest {
                 1,
                 1,
                 width,
-                RiverWidthProfile.constant(width),
                 bankWidth,
                 3D,
+                RiverBodyProfile.constant(width, bankWidth, 3D),
                 false,
                 false,
                 new RiverPolyline(
@@ -1347,55 +1709,45 @@ public class RiverNetworkTest {
         return hydraulicComparison != 0 ? hydraulicComparison : first.id().compareTo(second.id());
     }
 
-    private static ReachShape shapeOf(RiverReach reach, double meanderStrength) {
+    private static void assertWormBounds(RiverReach reach, double maximumOffset) {
+        assertTrue(maximumWormDisplacement(reach) <= maximumOffset + 0.0000001D);
+        RiverPolyline polyline = reach.polyline();
+        assertEquals(reach.from().x(), polyline.x(0), 0D);
+        assertEquals(reach.from().z(), polyline.z(0), 0D);
+        int last = polyline.size() - 1;
+        assertEquals(reach.to().x(), polyline.x(last), 0D);
+        assertEquals(reach.to().z(), polyline.z(last), 0D);
+    }
+
+    private static double maximumWormDisplacement(RiverReach reach) {
         RiverPolyline polyline = reach.polyline();
         double deltaX = reach.to().x() - reach.from().x();
         double deltaZ = reach.to().z() - reach.from().z();
-        double chordLength = StrictMath.hypot(deltaX, deltaZ);
-        double[] offsets = new double[polyline.size()];
-        double maximumOffset = 0D;
-        double weightedPosition = 0D;
-        double totalWeight = 0D;
-        int crossings = 0;
-        int previousSign = 0;
+        double maximumDisplacement = 0D;
         for (int point = 0; point < polyline.size(); point++) {
-            double pointX = polyline.x(point) - reach.from().x();
-            double pointZ = polyline.z(point) - reach.from().z();
-            double offset = (pointX * deltaZ - pointZ * deltaX) / chordLength;
-            offsets[point] = offset;
-            double absoluteOffset = StrictMath.abs(offset);
-            maximumOffset = StrictMath.max(maximumOffset, absoluteOffset);
             double t = (double) point / (polyline.size() - 1);
-            weightedPosition += t * absoluteOffset;
-            totalWeight += absoluteOffset;
-            int sign = absoluteOffset < meanderStrength * 0.05D ? 0 : offset < 0D ? -1 : 1;
-            if (sign != 0 && previousSign != 0 && sign != previousSign) {
-                crossings++;
+            double straightX = reach.from().x() + deltaX * t;
+            double straightZ = reach.from().z() + deltaZ * t;
+            double displacement = StrictMath.hypot(
+                    polyline.x(point) - straightX,
+                    polyline.z(point) - straightZ
+            );
+            maximumDisplacement = StrictMath.max(maximumDisplacement, displacement);
         }
-            if (sign != 0) {
-                previousSign = sign;
+        return maximumDisplacement;
     }
-            assertTrue(absoluteOffset <= meanderStrength + 0.0000001D);
+
+    private static boolean polylinesDiffer(RiverPolyline first, RiverPolyline second) {
+        if (first.size() != second.size()) {
+            return true;
         }
-        int dominantBand = 1;
-        double dominantEnergy = -1D;
-        int samples = offsets.length - 1;
-        for (int frequency = 1; frequency <= 8; frequency++) {
-            double cosine = 0D;
-            double sine = 0D;
-            for (int point = 0; point < samples; point++) {
-                double phase = TWO_PI_FOR_TESTS * frequency * point / samples;
-                cosine += offsets[point] * StrictMath.cos(phase);
-                sine += offsets[point] * StrictMath.sin(phase);
-            }
-            double energy = cosine * cosine + sine * sine;
-            if (energy > dominantEnergy) {
-                dominantEnergy = energy;
-                dominantBand = frequency;
+        for (int point = 0; point < first.size(); point++) {
+            if (Double.doubleToLongBits(first.x(point)) != Double.doubleToLongBits(second.x(point))
+                    || Double.doubleToLongBits(first.z(point)) != Double.doubleToLongBits(second.z(point))) {
+                return true;
             }
         }
-        double centroid = totalWeight <= 0.0000001D ? 0.5D : weightedPosition / totalWeight;
-        return new ReachShape(crossings, maximumOffset / meanderStrength, centroid, dominantBand);
+        return false;
     }
 
     private static long digest(RiverTile tile) {
@@ -1408,9 +1760,12 @@ public class RiverNetworkTest {
             hash = RiverNetwork.mix(hash ^ reach.order());
             hash = RiverNetwork.mix(hash ^ reach.state().ordinal());
             hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.width()));
-            for (int index = 0; index < reach.widthProfile().size(); index++) {
-                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.widthProfile().position(index)));
-                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.widthProfile().width(index)));
+            for (int index = 0; index < reach.bodyProfile().size(); index++) {
+                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bodyProfile().position(index)));
+                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bodyProfile().widthAtIndex(index)));
+                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bodyProfile().bankWidthAtIndex(index)));
+                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bodyProfile().depthAtIndex(index)));
+                hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bodyProfile().roofScaleAtIndex(index)));
             }
             hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.bankWidth()));
             hash = RiverNetwork.mix(hash ^ Double.doubleToLongBits(reach.depth()));
@@ -1442,7 +1797,7 @@ public class RiverNetworkTest {
         assertEquals(first.flow(), second.flow());
         assertEquals(first.order(), second.order());
         assertEquals(first.width(), second.width(), 0.0);
-        assertEquals(first.widthProfile(), second.widthProfile());
+        assertEquals(first.bodyProfile(), second.bodyProfile());
         assertEquals(first.bankWidth(), second.bankWidth(), 0.0);
         assertEquals(first.depth(), second.depth(), 0.0);
         assertEquals(first.mouth(), second.mouth());
@@ -1473,7 +1828,4 @@ public class RiverNetworkTest {
             return ocean && blockX >= 224;
         }
     }
-
-    private record ReachShape(int crossings, double amplitudeRatio, double centroid, int dominantBand) {
-    }
 }

core/src/test/java/art/arcane/iris/engine/river/RiverTileCacheTest.java

@@ -295,9 +295,9 @@ public class RiverTileCacheTest {
                 1,
                 1,
                 8.0,
-                RiverWidthProfile.constant(8.0),
                 4.0,
                 3.0,
+                RiverBodyProfile.constant(8.0, 4.0, 3.0),
                 false,
                 false,
                 new RiverPolyline(new double[]{8.0, 56.0}, new double[]{8.0, 8.0})

core/src/test/java/art/arcane/iris/engine/river/runtime/IrisRiverRuntimeTest.java

@@ -11,6 +11,7 @@ import art.arcane.iris.engine.object.IrisRiverOverride;
 import art.arcane.iris.engine.object.IrisRiverRoutingPolicy;
 import art.arcane.iris.engine.object.IrisRiverTerminalMode;
 import art.arcane.iris.engine.object.IrisRiverWaterMode;
+import art.arcane.iris.engine.object.IrisRiverWorm;
 import art.arcane.iris.engine.object.IrisStyledRange;
 import art.arcane.iris.engine.object.NoiseStyle;
 import art.arcane.iris.engine.river.RiverEdgeId;
@@ -20,14 +21,15 @@ import art.arcane.iris.engine.river.RiverPolyline;
 import art.arcane.iris.engine.river.RiverReach;
 import art.arcane.iris.engine.river.RiverRouteState;
 import art.arcane.iris.engine.river.RiverAnchor;
+import art.arcane.iris.engine.river.RiverBodyProfile;
 import art.arcane.iris.engine.river.RiverRoutingContext;
 import art.arcane.iris.engine.river.RiverTerrainNodeSample;
 import art.arcane.iris.engine.river.RiverTopologyComplexity;
 import art.arcane.iris.engine.river.RiverTerrainSourceSample;
-import art.arcane.iris.engine.river.RiverWidthProfile;
 import art.arcane.iris.util.project.interpolation.NoiseBounds;
 import art.arcane.iris.util.project.stream.ProceduralStream;
 import art.arcane.iris.util.project.stream.interpolation.Interpolated;
+import art.arcane.volmlib.util.collection.KList;
 import org.junit.Test;
 
 import java.util.HashMap;
@@ -793,9 +795,9 @@ public class IrisRiverRuntimeTest {
                 1,
                 1,
                 4D,
-                RiverWidthProfile.constant(4D),
                 2D,
                 4D,
+                RiverBodyProfile.constant(4D, 2D, 4D),
                 true,
                 false,
                 new RiverPolyline(new double[]{-600D, 0D}, new double[]{0D, 0D})
@@ -1004,8 +1006,12 @@ public class IrisRiverRuntimeTest {
                 .setBankWidth(range(12D))
                 .setDepth(range(5D))
                 .setMaxIncision(512)
-                .setMeanderStrength(0D)
-                .setMeanderStyle(flat())
+                .setWorms(new KList<>(new IrisRiverWorm()
+                        .setSeed(1L)
+                        .setTortuosity(0D)
+                        .setDetailTortuosity(0D)
+                        .setMaxOffset(0D)
+                        .setSegments(1)))
                 .setBedRoughness(0D)
                 .setBedRoughnessStyle(flat())
                 .setDryContinuationChance(1D);