Default Placement Modifiers

Placement modifiers add conditions for the placement of features and dynamically modify where they generate in the world. Below is a list of all default placement modifiers included in AbyssalLib.

CountModifier

ID: abyssallib:count

Duplicates the incoming position stream a specified number of times.

Parameter	Information
`count`	The number of times to duplicate the input positions.

HeightRangeModifier

ID: abyssallib:height_range

Randomizes the Y-coordinate of input positions between a specified minimum and maximum bounds.

Parameter	Information
`min_inclusive`	The minimum allowed Y coordinate (inclusive).
`max_inclusive`	The maximum allowed Y coordinate (inclusive).

InSquareModifier

ID: abyssallib:in_square

Spreads the input positions randomly across the X and Z axes within the bounds of a standard 16x16 chunk.

(No parameters required)

EnvironmentScanModifier

ID: abyssallib:environment_scan

Performs a vertical scan to find the nearest solid surface.

Parameter	Information
`max_steps`	The maximum number of blocks to scan in the specified direction.
`up`	Determines the scan direction; `true` to scan upwards, `false` to scan downwards.

BlockFilterModifier

ID: abyssallib:block_filter

Filters out incoming positions based on the target block type.

Parameter	Information
`targets`	The list of allowed block info targets.
`offset`	The coordinate offset to check relative to the current placement position.

BiomeFilterModifier

ID: abyssallib:biome_filter

Filters positions based on the active biome at the coordinates.

Parameter	Information
`allowed_biomes`	The list of acceptable biome identifiers (e.g., `"minecraft:plains"`).

ChanceModifier

ID: abyssallib:chance

Filters positions based on a random probability.

Parameter	Information
`chance`	The denominator for the 1-in-X probability. Must be >= 1.

RandomOffsetModifier

ID: abyssallib:random_offset

Slightly shifts the incoming position randomly along all three axes based on the defined spread values.

Parameter	Information
`xz_spread`	The maximum horizontal distance (positive or negative) to offset the position.
`y_spread`	The maximum vertical distance (positive or negative) to offset the position.

HeightmapModifier

ID: abyssallib:heightmap

Snaps the Y-coordinate of incoming positions to the highest block at that specific X and Z coordinate, dictated by a selected heightmap.

Parameter	Information
`heightmap`	The heightmap projection to use when calculating the surface.

RarityFilterModifier

ID: abyssallib:rarity_filter

Acts as a per-chunk probability gate. Unlike the standard ChanceModifier which evaluates each generated vector individually, this modifier evaluates the probability exactly once per stream execution.

Parameter	Information
`chance`	The denominator for the 1-in-X probability per chunk.

WaterDepthFilterModifier

ID: abyssallib:water_depth_filter

Filters positions based on the depth of the water column above them.

Parameter	Information
`max_depth`	The maximum allowed number of contiguous water blocks directly above the position.

NoiseThresholdModifier

ID: abyssallib:noise_threshold

Filters positions based on 2D simplex noise.

Parameter	Information
`frequency`	The frequency multiplier applied to coordinates before sampling noise.
`threshold`	The threshold value to compare the sampled noise against.
`above_threshold`	Whether the noise value must be above or below the threshold.

NoiseCountModifier

ID: abyssallib:noise_count

Duplicates the incoming position stream a variable number of times based on a 2D simplex noise evaluation.

Parameter	Information
`frequency`	The frequency multiplier applied to coordinates before sampling the noise field.
`threshold`	The noise value boundary determining which count is used.
`count_above`	The number of positions to yield if the sampled noise is strictly greater than the threshold.
`count_below`	The number of positions to yield if the sampled noise is less than or equal to the threshold.

SurfaceRelativeThresholdModifier

ID: abyssallib:surface_relative_threshold

Filters positions based on their vertical proximity to a selected world heightmap (surface).

Parameter	Information
`heightmap`	The heightmap criteria used to locate the surface block.
`min_inclusive`	The minimum allowed relative offset from the surface (inclusive).
`max_inclusive`	The maximum allowed relative offset from the surface (inclusive).

BiomeTransitionModifier

ID: abyssallib:biome_transition

Prevents feature bleeding across chunk boundaries.

(No parameters required)

CountOnEveryLayerModifier

ID: abyssallib:count_on_every_layer

Duplicates the incoming position stream across every single Y-coordinate from the bottom of the world to the top.

Parameter	Information
`count`	The number of placement attempts to make per Y-layer.

FixedPlacementModifier

ID: abyssallib:fixed_placement

Completely overrides the procedural generation stream, replacing it with a fixed, hardcoded list of specific coordinates.

Parameter	Information
`positions`	The static list of absolute world coordinates.

05 June 2026