Material rule

Helpers that build a minecraft:material_rule object, one for each of its types. Where a field takes one, write the helper's call; its name is the type it makes. Click a type to see what it accepts.

Bandlands makes minecraft:bandlands

Places the striped terracotta of badlands, with the colour picked by height.

Bandlands()

SurfaceRule stripes = If(YAbove(63)) { Bandlands() }

Block makes minecraft:block

Places one block. Writing just a block id where a rule is expected does the same thing.

Block(result_state)

result_state: BlockState
The block, with optional state such as oak_log[axis = y].

SurfaceRule floor = Block(stone)

Condition makes minecraft:condition

Runs then_run only where if_true passes. Usually written If(condition) { rules }.

Condition(if_true, then_run)

if_true: MaterialConditionRef
The condition to test.
then_run: MaterialRuleRef
The rule to run when it passes.

SurfaceRule grass = If(StoneDepth(Floor)) { Block(grass_block) }

OreVein makes minecraft:ore_vein

OreVein(ore_block, raw_ore_block, filler_block, raw_ore_chance, density, richness, filler_gap)

ore_block: BlockState
raw_ore_block: BlockState
filler_block: BlockState
raw_ore_chance: number 0..1
density: DensityFunctionRef
richness: DensityFunctionRef
filler_gap: DensityFunctionRef

Sequence makes minecraft:sequence

Tries each rule in order and stops at the first one that places a block. A list [a, b], or several rules in an If { } body, makes the same thing.

Sequence(sequence)

sequence: list of MaterialRuleRef
The rules, in order.

SurfaceRule top = [
  If(StoneDepth(Floor)) { Block(grass_block) },
  Block(dirt),
]