Providers

Most worldgen fields do not take a plain number: they take a provider, a small object the game samples at every position. That is how one ore configuration can produce veins of varying size, or one carver can dig tunnels at varying heights.

Four families exist, and they show up across carvers, features, structures and material rules:

• Vertical anchors - a single Y level, expressed absolutely or relative to the world bounds.
• Height providers - a distribution of vertical anchors.
• Int providers - a distribution of integers, for counts and sizes.
• Float providers - a distribution of floats, for radii, chances and scales.

Every builder is scoped: it only resolves inside a block actually accepting that kind of value, so nothing pollutes the global completion list.

Vertical Anchors

A vertical anchor is one Y level. It serializes as a one-key object, and the resolved Y is never clamped, so an anchor can point outside the build height of the dimension.

In the Overworld, aboveBottom(0) is Y -64, belowTop(0) is Y 319 and relativeToSeaLevel(0) is Y 63. The Nether and the End resolve against the 128 blocks of their noise settings: bottom Y 0, top Y 127, sea level 32 and 0. The diagram below places each anchor on the world column and shades the range of a uniformHeightProvider, next to its Kotlin call and JSON:

uniformHeightProvider(aboveBottom(8), absolute(180))

{
	"type": "minecraft:uniform",
	"min_inclusive": {
		"above_bottom": 8
	},
	"max_inclusive": {
		"absolute": 180
	}
}

Reference: Vertical anchor

Height Providers

A height provider picks a Y level between two anchors, following a distribution. It is what heightRange() on a placed feature, y on a carver and startHeight on a jigsaw structure take.

Every builder except weightedListHeightProvider also takes plain Int bounds, read as absolute Y coordinates.

heightRange(uniformHeightProvider(minInclusive = 0, maxInclusive = 64))
heightRange(trapezoidHeightProvider(minInclusive = 0, maxInclusive = 64, plateau = 20))
heightRange(constantAbsolute(32))
heightRange(constantHeightProvider(belowTop(16)))
heightRange(veryBiasedToBottomHeightProvider(aboveBottom(8), absolute(16)))

heightRange(weightedListHeightProvider {
	entry(3, constantAbsolute(32))
	entry(1, uniformHeightProvider(aboveBottom(0), absolute(16)))
})

Reference: Height provider

Int Providers

Int providers fill every field expecting a variable count or size: count() and countOnEveryLayer() on placed features, the limit of a capped processor, the layer heights of a blockColumn, and so on.

Each provider has its own distribution shape. The explorer below samples one 10 000 times with the game's formulas, for your parameters or a vanilla value, and prints the matching Kotlin call and JSON (every provider above except weightedList).

uniform(minInclusive = 1, maxInclusive = 5)

{
	"type": "minecraft:uniform",
	"min_inclusive": 1,
	"max_inclusive": 5
}

// A plain Int is a constant, only count() and countOnEveryLayer() accept it.
count(10)
count(biasedToBottom(3, 8))
count(clampedNormal(1, 10, mean = 5.0f, deviation = 2.0f))

// Reroll uniform(0, 20), but never below 4 or above 12.
count(clamped(4, 12, uniform(0, 20)))

// 70% chance of 1, 30% chance of 3.
count(weightedList {
	entry(7, constant(1))
	entry(3, constant(3))
})

// Same pool, written as weight-to-provider pairs.
count(weightedList(7 to constant(1), 3 to constant(3)))

Reference: Int provider

Float Providers

Float providers fill float fields such as roomVerticalRadiusMultiplier and floorLevel on carvers, radius on foliage placers, heightScale and stalactiteBluntness on features, and volume or pitch on enchantment effects.

floorLevel = constant(-0.5f)
pitch = uniform(0.8f, 1.2f)
roomVerticalRadiusMultiplier = clampedNormal(mean = 0.5f, deviation = 0.2f, min = 0.0f, max = 1.0f)
thickness = trapezoid(min = 0.0f, max = 2.0f, plateau = 0.5f)

The explorer under the int providers table also covers the float providers.

constant, uniform, trapezoid and clampedNormal are named the same for ints and floats. A block accepting both, such as largeDripstone { }, tells them apart by argument type: constant(3) builds an int provider and constant(3f) a float one.

Reference: Float provider

See Also

• Carvers - y, count, radius multipliers and canyon shape fields
• Features - heightRange, count and the configured feature parameters
• Noise & Terrain - yAbove and verticalGradient material rule conditions
• Structures - startHeight on jigsaw structures, height on nether fossils