3D optimization: visibility, bounds and groups
Avoid unnecessary geometry without losing visible objects to incorrect AABBs.
Different ways to reduce work
Frustum culling rejects an object using camera bounds; occlusion culling uses information about objects hiding other objects. These are different mechanisms. A Z-buffer alone does not remove all hidden-geometry CPU preparation, vertex work and submission.
Distance simplification, visibility limits, simpler shadows and level partitioning address different costs. Change them for a measured bottleneck and inspect transitions. Distance visibility does not automatically stream world data in or out.
Account for group size
MultiMesh stores individual transforms in a buffer while the group uses combined bounds for visibility. A city-sized group may stay visible when the camera sees only a small section. Partition spatially when culling savings justify extra groups and submissions.
| Situation | Check |
|---|---|
| Object disappears with camera movement | Bounds, transform, layer and visibility range |
| Tail or effect edge disappears | GPU deformation and AABB margin |
| Only a small part of a large school is seen | Combined bounds and group size |
| Silhouette or shadows changed after optimization | Whether necessary visual work was removed |
Bounds for GPU animation
The MultiMesh example sets CustomAabb. Particles use VisibilityAabb with motion margin. GPU vertex deformation does not automatically supply appropriate CPU bounds for every pose.
Particle CaptureAabb estimates current state with possible lag and GPU-buffer readback. For known bounded animation, explicit safe bounds avoid per-frame readback. An infinitely large AABB is not a universal fix for disappearing objects.
Check actual cost
This example uses an opaque unshaded material without shadows. It does not replace testing a lit model with transparency, shadows and effects. Depth prepass settings and individual techniques depend on the rendering method; they are not identical guarantees for Forward+, Mobile and Compatibility.