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

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.