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Biomes

Biomes define climate, visuals, mob spawns, carvers, and the placed features list for each decoration step. In Minecraft, biomes control not just the terrain appearance but also weather behavior, mob spawning rules, and which features generate.

How Biomes Work

In the Overworld, biome placement is determined by 6 climate parameters:

Temperature - Controls snow/ice coverage and vegetation types (5 levels from frozen to hot)
Humidity - Affects vegetation density (5 levels from arid to humid)
Continentalness - Determines ocean/beach/inland placement
Erosion - Controls flat vs mountainous terrain (7 levels)
Weirdness - Triggers biome variants (e.g., Jungle → Bamboo Jungle)
Depth - Determines surface vs cave biomes

These parameters form a 6D space where each biome occupies defined intervals. The game selects the closest matching biome for any given location.

References: Biome, Biome definition

Basic Biome

val myBiome = dp.biome("my_biome") {
	temperature = 0.8f
	downfall = 0.4f
	hasPrecipitation = true

	attributes {
		skyColor(0x78A7FF)
		fogColor(0xC0D8FF)
		waterFogColor(0x050533)
	}

	effects {
		waterColor = color(0x3F76E4)
	}
}

Environment Attributes

Biome visuals/audio/gameplay are partially controlled by environment attributes (attributes), a shared system used by both biomes and dimension types. See the Environment Attributes page for the full list of attributes, modifiers, and interpolation rules.

attributes {
	// Simple values serialize as a raw JSON value (equivalent to "minecraft:override")
	skyColor(0x78A7FF)

	// Expanded form when a modifier is provided
	fogColor(0xC0D8FF, AttributeModifier.ADD)
}

Effects

The effects block controls biome-specific colors like water/foliage/grass. Visual sky/fog/water fog, particles and sounds are handled by attributes.

Reference: Biome definition - Effects

effects {
	// Water color (serialized as a decimal int in JSON)
	waterColor = color(0x3F76E4)

	// Optional colors
	foliageColor = color(0x59AE30)
	grassColor = color(0x79C05A)
}

Spawners

Define mob spawn rules per category. Each spawner entry specifies the entity type, spawn weight (relative probability), and count range. Higher weights mean more frequent spawns relative to other entries in the same category.

Reference: Biome definition - Mob spawning

spawners {
	creature {
		spawner(EntityTypes.COW, weight = 6, minCount = 2, maxCount = 4)
		spawner(EntityTypes.SHEEP, weight = 8, minCount = 2, maxCount = 4)
	}
	monster {
		spawner(EntityTypes.SKELETON, weight = 80, minCount = 1, maxCount = 2)
		spawner(EntityTypes.ZOMBIE, weight = 80, minCount = 1, maxCount = 2)
	}
	// Other categories: ambient, waterCreature, undergroundWaterCreature, waterAmbient, misc, axolotls
}

Spawn Costs

Spawn costs control mob density using an energy budget system. Each mob type has an energyBudget (max population density) and charge ( cost per mob). This prevents overcrowding while allowing natural mob distribution.

Reference: Biome definition - Spawn costs

spawnCosts {
	this[EntityTypes.COW] = spawnCost(energyBudget = 1.2f, charge = 0.1f)
	this[EntityTypes.SHEEP] = spawnCost(energyBudget = 1.0f, charge = 0.08f)
}

Carvers

Carvers hollow out terrain to create caves and canyons. They run during the carvers generation step, after terrain noise but before features. Two carving modes exist: air for standard caves and liquid for underwater caves.

Reference: Carver

carvers {
	air(myCaveCarver)        // Carves air (caves)
	liquid(myUnderwaterCave) // Carves underwater caves
}

See Carvers below for creating configured carvers.

Features

Features are attached to biomes via decoration steps. Each step runs in order during chunk generation, with structures placing before features within the same step. See the main worldgen page for the full step list.

Reference: Biome definition - Features

features {
	fluidSprings = listOf(...)
	lakes = listOf(...)
	localModifications = listOf(...)
	rawGeneration = listOf(...)
	strongholds = listOf(...)
	surfaceStructures = listOf(...)
	topLayerModification = listOf(...)
	undergroundDecoration = listOf(...)
	undergroundOres = listOf(orePlaced)
	undergroundStructures = listOf(...)
	vegetalDecoration = listOf(treePlaced, flowerPlaced)
}

See Features for creating configured and placed features.

Carvers (Caves/Canyons)

Configured carvers remove terrain to form cave systems and canyons. They use noise-based algorithms to create natural-looking underground spaces. Carvers run after terrain generation but before features, ensuring caves don't destroy placed decorations.

Minecraft has two carver types:

Cave carvers - Create winding tunnel systems with variable radius
Canyon carvers - Create deep ravines with steep walls

References: Carver, Configured carver

Cave Carver

val caveCfg = caveConfig {
	floorLevel = constant(-0.2f)
	horizontalRadiusMultiplier = constant(1.0f)
	lavaLevel = absolute(8)
	probability = 0.08
	verticalRadiusMultiplier = constant(0.7f)
	y = uniformHeightProvider(32, 128)
	yScale = constant(0.5f)
}

val cave = dp.configuredCarver("my_cave", caveCfg) {}

Canyon Carver

val canyonCfg = canyonConfig {
	lavaLevel = absolute(8)
	probability = 0.02
	y = uniformHeightProvider(10, 67)
	yScale = constant(3.0f)
	// Additional canyon-specific settings...
}

val canyon = dp.configuredCarver("my_canyon", canyonCfg) {}

Complete Biome Example

fun DataPack.createHighlandsBiome() {
	// Create a cave carver
	val caveCfg = caveConfig {
		floorLevel = constant(-0.2f)
		horizontalRadiusMultiplier = constant(1.0f)
		lavaLevel = absolute(8)
		probability = 0.08
		verticalRadiusMultiplier = constant(0.7f)
		y = uniformHeightProvider(32, 128)
		yScale = constant(0.5f)
	}
	val cave = configuredCarver("highlands_cave", caveCfg) {}

	// Create placed features (see Features page)
	val treePlaced = /* ... */
	val orePlaced = /* ... */

		// Create the biome
		biome("highlands") {
			temperature = 0.8f
			downfall = 0.3f
			hasPrecipitation = true

			attributes {
				fogColor(0xBFEFFF)
				skyColor(0x99D9FF)
				waterFogColor(0x0A2C4F)
			}

			effects {
				waterColor = color(0x34A7F0)
			}

			spawners {
				creature {
					spawner(EntityTypes.COW, 6, 2, 4)
					spawner(EntityTypes.SHEEP, 8, 2, 4)
				}
				monster {
					spawner(EntityTypes.SKELETON, 80, 1, 2)
					spawner(EntityTypes.ZOMBIE, 80, 1, 2)
				}
			}

			spawnCosts {
				this[EntityTypes.COW] = spawnCost(1.2f, 0.1f)
				this[EntityTypes.SHEEP] = spawnCost(1.0f, 0.08f)
			}

			carvers { air(cave) }

			features {
				undergroundOres = listOf(orePlaced)
				vegetalDecoration = listOf(treePlaced)
			}
		}
}

linkBiomes

linkHow Biomes Work

linkBasic Biome

linkEnvironment Attributes

linkEffects

linkSpawners

linkSpawn Costs

linkCarvers

linkFeatures

linkCarvers (Caves/Canyons)

linkCave Carver

linkCanyon Carver

linkComplete Biome Example

linkSee Also