Quick answer: Raise Sim Steps in the ProceduralFoliageSpawner to 50–100, balance per-FoliageType Initial Seed Density, and check Steepness/Ground Slope angle limits.
A procedural forest produces dense clumps in the center and empty edges. The simulation favors aggressive species and the volume isn’t finishing its competition cycle.
The Simulation Model
ProceduralFoliage simulates plant growth and competition over multiple steps. Each step, plants spread seeds, compete for space, and die from overcrowding. Final distribution emerges from these dynamics.
Tune Sim Steps
Open the ProceduralFoliageSpawner asset. Set Num Steps to 50–100. Each step refines the competition; too few = uneven; too many = no further change but longer bake.
Per-FoliageType Tuning
For each FoliageType in the spawner’s list:
- Initial Seed Density: plants per square meter at start. High species dominate; pick values balanced for the mix.
- Average Spread Distance: how far seeds disperse. Low = clumpy, high = spread.
- Max Age: plants live this many sim cycles. Long-lived dominate.
- Steepness: max ground slope (degrees). Filters placement.
Resimulate After Edits
Right-click the volume → Resimulate. Sim runs again with new params; foliage redistributes. Save and check.
Exclusion Volumes
A ProceduralFoliageBlockingVolume excludes regions from spawning. Useful for paths and clearings. Verify none accidentally cover your empty patches.
Verifying
Resimulate. Visualize with Show → Procedural Foliage. Distribution should look organic: variety across the volume, no obvious clumps or holes (other than intended exclusion zones).
“Procedural foliage is a balance act between species. Higher Sim Steps + balanced densities = natural-looking forests.”
Bake foliage placements before shipping — runtime resimulation is for editing, not gameplay.