Basic biomes customization
This page focuses on the basics of creating and editing biomes including changing ground and water blocks, ore generation, tree/plant spawning and creating hills/pits. For info on the ReplacedBlocks feature, using CustomHeightControl and more difficult features like waterfalls see Advance Biomes Customization (Under Construction).
Biome editing may be broken into four main parts: biome placement, terrain shape, biome population and appearance. For information on biome placement see this tutorial.
The basic shape of the terrain is affected by a lt of variables. You can change the height, how hilly it is and up to what level air blocks should be filled with water blocks. The shape of the terrain is forming during the first pass of terrain generation, just after the biomes have been calculated.
The first and most important variable in determining a biomes height is the BiomeHeight setting. This variable is dependent on what WorldHeightBits is set to in the worldconfig. Minecraft divides the terrain height it generates into equal positive and negative values with a BiomeHeight of 0.0 representing the middle. On default settings (WorldHeightBits:7) the terrain will generate up to 128 blocks in height, which would put BiomeHeight:0.0 at y=64. If WorldHeightBits is changed to 8 then the generation height doubles to 256, and every height settings effect roughly doubles. BiomeHeight:0.0 becomes y=128 and upping it to 0.1 will have double the effect of raising it to 0.1 on WorldHeightBits:7. Upping the WorldHeightBits to 8 is necessary to get terrain generation up to the maximum of 256. WorldHeightBits may be lowered to have the opposite effect, with each step lower the terrain generation max height will be cut in half. A WorldHeightBits of 6 would not generate terrain above y=64. Note: these two features do not work if the generator is set to OldGenerator in the WorldConfig.
Changing ExtraBiomeHeight can create overhangs and cliffs 8 times its value. Changing ExtraHeightConstrictWaist determines how the cliffs generate. Keeping values between -0.4 and 1.0, positive values give the cliffs an hour glass like shape by removing the middle region (4 x ExtraBiomeHeight). Greater than 1.0 can cause hanging and floating terrain. Negative values cause the middle region (4 x ExtraBiomeHeight) to expand. Decreasing below -0.4 can start to create shelves that can have massive caves beneath.
The following table can help with determining what height settings to use based on WorldHeightBits of 7 and 8. Do not use -2.0 as a BiomeHeight setting as this is bugged (causes a division by zero). Also note the terrain will not generate to the max of 256 and will stop at 255, if not a few blocks before that. BiomeHeight may have any value between -10 and 10, although any value above/below 4/-4 has no further effect.
| BiomeHeight | WorldHeightBits:7 | WorldHeightBits:8 |
|---|---|---|
| -4 | 0 | 0 |
| -3.5 | 7 | 10 |
| -3 | 16 | 28 |
| -2.5 | 24 | 45 |
| -2 | Error | Error |
| -1.99 | 32 | 60 |
| -1.5 | 40 | 78 |
| -1 | 48 | 95 |
| -0.5 | 57 | 111 |
| 0 | 67 | 128 |
| 0.5 | 76 | 144 |
| 1 | 85 | 156 |
| 1.5 | 94 | 173 |
| 2 | 102 | 190 |
| 2.5 | 111 | 207 |
| 3 | 119 | 223 |
| 3.5 | 128 | 240 |
| 4 | 128 | 255 |
There are a lot of settings to fine-tune how hilly the terrain is. The most important of them is BiomeVolatility. Increasing it will make the terrain more hilly. 0.0 makes the terrain almost flat. A value of 1.0 will give you hills. 2.0 gives you cliffs. Just like BiomeHeight the effects are doubled on WorldHeightBits:8. This setting does not work on TerrainMode:OldGenerator.
During the second pass of terrain generation the biomes are populated with resources like ores, trees, custom objects, flowers, tall grasses and small ponds above/below sea level. After this is done, biomes with a low BiomeTemperature will be covered in snow.
You can find all resources in the Resources queue.
There are things that haven't got anything to do with terrain generation, but that you still want to change. For exampe, uou can edit the colors and weather of the biome. Sadly, the vanilla singleplayer client will ignore all those settings. It will also display custom (non-vanilla) biomes with the colors and weather of the plains biome. Players will need to install the Forge version of Terrain Control to fix this.
These settings, along with a description, can be found here.
