FScatterVariety

One grass variety on one paint layer, in plain C++: the shell turns a ULandscapeGrassType variety plus a layer set entry (FOrreryTerrainLayerGrass) into this.

Declaration

struct FScatterVariety

Header: #include "Native/TerrainScatter.h"
Module: PublicDependencyModuleNames.Add("OrreryTerrainCore"); in your module’s Build.cs.
Stability: Experimental: supported, may change in a minor version, with a changelog line.
Thread: Tier 1: plain C++, no allocation, deterministic in canonical order (ascending candidate index), any thread. (the header’s rule)

Properties

Name	Type	Default	Meaning
`Seed`	`uint64_t`	`0`	ScatterVarietySeed(package path, variety index): part of every key.
`Layer`	`int32_t`	`0`	Paint layer whose effective weight drives the keep test, 0..255.
`DensityPer100m2`	`float`	`0.f`	Candidates per 100 m²: the variety's density × the entry's DensityScale.
`bUseGrid`	`bool`	`false`	Jittered grid instead of the Halton(2,3) sequence.
`PlacementJitter`	`float`	`1.f`	Grid only, 0..1 of a grid step.
`MinWeight`	`float`	`0.f`	AllowedDensityRange.Min: kept only when W > MinWeight.
`MaxWeight`	`float`	`1.f`	AllowedDensityRange.Max: kept only when W <= MaxWeight.
`Scaling`	`EScatterScaling`	`EScatterScaling::Uniform`	—
`ScaleX`	`float`	`{1.f, 1.f}`	Min, max.
`ScaleY`	`float`	`{1.f, 1.f}`	—
`ScaleZ`	`float`	`{1.f, 1.f}`	—
`bWeightAttenuatesMaxScale`	`bool`	`false`	A low weight lowers the scale's upper end.
`MaxScaleWeightAttenuation`	`float`	`0.5f`	With bWeightAttenuatesMaxScale, 0..1: the weights from this value to 1 map the upper end of each scale range from its minimum to its maximum; at or below it the upper end is the minimum (ULandscapeGrassType's public doc).
`bRandomRotation`	`bool`	`true`	Yaw from the key; else 0.
`bAlignToSurface`	`bool`	`true`	Output the surface normal; else +Z.
`bAlignToTriangleNormals`	`bool`	`false`	The cell's triangle normal instead of the bilinear post normal. ULandscapeGrassType applies its flag to the grid only ("Halton always uses triangle normal"): the shell sets this for Halton varieties to match.
`SlopeRangeDeg`	`float`	`{0.f, 90.f}`	Grows inside this slope band, degrees (the slope the material reads).
`SlopeFadeDeg`	`float`	`3.f`	Smoothstep fade outside the band, degrees.
`AltitudeRangeM`	`float`	`{-1.0e6f, 1.0e6f}`	Grows inside this world-altitude band, metres (world Z, no AutoNoise offset).
`AltitudeFadeM`	`float`	`5.f`	Smoothstep fade outside the band, metres.
`GroundClassMask`	`uint32_t`	`0xFFFFFFFFu`	Bit c: grows on ground class c (c < 31); bit 31: classes 31 and above.
`bOnPlates`	`bool`	`false`	Grows inside plate footprints (cleared by default).
`KeepClearMarginCm`	`float`	`100.f`	Cleared within this distance of a corridor or opening footprint, cm.