Actually gets to world gen now B)

src/main/java/com/dfsek/terra/biome/BiomeZone.java

@@ -26,7 +26,7 @@ public class BiomeZone {
         this.noise.setNoiseType(FastNoiseLite.NoiseType.OpenSimplex2);
         this.noise.setFractalType(FastNoiseLite.FractalType.FBm);
         this.noise.setFractalOctaves(4);
-        this.noise.setFrequency(wc.getConfig().getTemplate().getZoneFreq());
+        this.noise.setFrequency(1D / wc.getConfig().getTemplate().getZoneFreq());
         this.grids = grids;
         imageLoader = wc.imageLoader;
         useImage = wc.fromImage;

src/main/java/com/dfsek/terra/biome/UserDefinedBiome.java

@@ -4,13 +4,16 @@ import com.dfsek.terra.WorldObject;
 import com.dfsek.terra.config.builder.GeneratorBuilder;
 import com.dfsek.terra.config.templates.BiomeTemplate;
 import com.dfsek.terra.generation.UserDefinedDecorator;
+import com.dfsek.terra.generation.config.WorldGenerator;
 import org.bukkit.World;
 import org.polydev.gaea.biome.Biome;
 import org.polydev.gaea.biome.Decorator;
 import org.polydev.gaea.biome.Generator;
 import org.polydev.gaea.structures.features.Feature;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Class representing a config-defined biome
@@ -22,6 +25,7 @@ public class UserDefinedBiome implements Biome, WorldObject {
     private final String id;
     private final BiomeTemplate config;
     private final boolean erode;
+    private final Map<World, WorldGenerator> gens = new HashMap<>();
 
 
     public UserDefinedBiome(org.bukkit.block.Biome vanilla, UserDefinedDecorator dec, GeneratorBuilder gen, boolean erode, BiomeTemplate config) {
@@ -87,6 +91,6 @@ public class UserDefinedBiome implements Biome, WorldObject {
 
     @Override
     public Generator getGenerator(World w) {
-        return gen.build(w.getSeed());
+        return gens.computeIfAbsent(w, world -> gen.build(world.getSeed()));
     }
 }

src/main/java/com/dfsek/terra/biome/palette/PaletteHolderBuilder.java

@@ -1,6 +1,7 @@
 package com.dfsek.terra.biome.palette;
 
 import com.dfsek.terra.util.DataUtil;
+import net.jafama.FastMath;
 import org.bukkit.block.data.BlockData;
 import org.polydev.gaea.world.palette.Palette;
 
@@ -18,7 +19,7 @@ public class PaletteHolderBuilder {
     @SuppressWarnings("unchecked")
     public PaletteHolder build() {
         Palette<BlockData>[] palettes = new Palette[paletteMap.lastKey() + 1];
-        for(int y = 0; y <= paletteMap.lastKey(); y++) {
+        for(int y = 0; y <= FastMath.max(paletteMap.lastKey(), 255); y++) {
             Palette<BlockData> d = DataUtil.BLANK_PALETTE;
             for(Map.Entry<Integer, Palette<BlockData>> e : paletteMap.entrySet()) {
                 if(e.getKey() >= y) {

src/main/java/com/dfsek/terra/biome/palette/PaletteLayer.java

@@ -1,17 +1,19 @@
 package com.dfsek.terra.biome.palette;
 
 import org.bukkit.block.data.BlockData;
+import org.jetbrains.annotations.NotNull;
 import org.polydev.gaea.math.ProbabilityCollection;
 
 public class PaletteLayer {
     private final ProbabilityCollection<BlockData> layer;
     private final int size;
 
-    public PaletteLayer(ProbabilityCollection<BlockData> layer, int size) {
+    public PaletteLayer(@NotNull ProbabilityCollection<BlockData> layer, int size) {
         this.layer = layer;
         this.size = size;
     }
 
+    @NotNull
     public ProbabilityCollection<BlockData> getLayer() {
         return layer;
     }

src/main/java/com/dfsek/terra/biome/palette/SinglePalette.java

@@ -0,0 +1,16 @@
+package com.dfsek.terra.biome.palette;
+
+import org.polydev.gaea.world.palette.Palette;
+
+public class SinglePalette<E> extends Palette<E> {
+    private final E item;
+
+    public SinglePalette(E item) {
+        this.item = item;
+    }
+
+    @Override
+    public E get(int i, int i1, int i2) {
+        return item;
+    }
+}