Sampling, filtering, and spawning

Surface scatter procedure

1. Obtain actor/landscape/surface data within explicit component bounds.
2. Use Surface Sampler or the appropriate sampler to produce candidate points.
3. Project/re-project after transforms that move points off the target surface.
4. Compute slope, height, surface type/tag, density, and clearance attributes.
5. Apply hard filters before random thinning.
6. Subtract roads, structures, water, paths, and gameplay-clearance shapes with Difference or point filters.
7. Use density/weights for natural distribution and mesh choice.
8. Transform points within bounded rotation/scale ranges.
9. Inspect points and bounds before Static Mesh Spawner/Spawn Actor.

Exclusion and spacing

• Use spatial Difference for clear exclusion shapes.
• Use Distance to create a gradient near another point set; filter/remap the result.
• Use Self Pruning or neighborhood logic for overlap/spacing, choosing bounds and pruning order intentionally.
• Account for final mesh bounds, not only pivot distance.
• Keep critical traversal and gameplay sightlines as hard constraints, never probability alone.

Mesh selection

• Drive mesh/material/scale selection from explicit attributes or weighted selector data.
• Use Data Tables/Attribute Sets plus Match And Set Attributes for editable catalogs.
• Keep asset references soft/async where the generation and loading model requires it.
• Prefer instancing for repeated static meshes; use Actors only when Actor behavior is required.

Spline pattern

1. Get Spline Data from the intended actor/component.
2. Sample by distance, subdivision, or control-point semantics appropriate to the asset.
3. Write tangent/orientation/width/side attributes.
4. Offset or project candidates.
5. Exclude intersections and invalid surface regions.
6. Spawn fence posts, roadside objects, or downstream spline/mesh data.

Use Shape Grammar when a repeatable module grammar materially simplifies fences/buildings; do not force grammar onto free-form scatter.

Spawn-output selector

Output	Use
ISM/HISM/static mesh spawner	repeated static visual content
Spawn Actor	behavior, identity, components, or independent lifecycle required
Output node data	downstream PCG component/subgraph consumes points/attributes
PCG Data Asset	reusable baked data exchange

Do not spawn thousands of Actors for decoration. Do not use GPU procedural instances for outputs that need collision, nav, HLOD, persistence, ray tracing, or distance fields.