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Cull Distance, Lightmass, PVS, HLOD Volumes

A grab-bag of optimization volumes.

CullDistanceVolume

Per-region maximum draw distance keyed by mesh size. Tiny meshes get culled early, big meshes draw further.

Property Effect
Cull Distances Array of (Size, Distance) pairs
Enabled Master toggle

For a typical scene:

Size 10 → Distance 1000
Size 50 → Distance 5000
Size 200 → Distance 20000
Size 1000 → Distance 100000

The "size" measure is the actor's bounding box max dimension. Any static mesh inside the volume gets the matching distance interpolated.

Per-actor override: Cull Distance on StaticMeshComponent. Volume only applies if the per-actor value is 0.

LightmassImportanceVolume

For projects still using Lightmass static lighting (not Lumen), this volume restricts photon distribution to the region inside. Bakes faster, higher quality where you care.

Lumen-only projects can ignore this — no Lightmass means no bake.

PrecomputedVisibilityVolume

Static potentially-visible-set computation. Used on mobile / older hardware where dynamic occlusion is too expensive.

  1. Project Settings → Precompute Visibility = true
  2. Place a PrecomputedVisibilityVolume covering player-reachable areas
  3. Build lighting — the visibility data is baked alongside lightmaps

Skips draw calls for actors known to be invisible from inside any sample point.

HLOD / Mesh Merging Volumes

Within a MeshMergingVolume, static meshes auto-merge for HLOD generation (Hierarchical LOD — proxy meshes used at distance in World Partition).

  • Project Settings → World Settings → HLOD Setup drives the proxy strategy.
  • For World Partition, use HLOD Layer data assets to declare which actors merge into which proxy.

Combining

These volumes don't interfere with each other or with PostProcess / Trigger / Physics volumes — they all evaluate independently per-actor.