Non-Adjacent Collision Meshes Do Not Clash#

Code

BA.002

Validator

Compatibility

Tags

Summary#

Collision meshes on non-adjacent links in the articulation hierarchy must not overlap or intersect.

Why#

When collision meshes on non-adjacent links overlap, it causes:

  • Physics simulation instability at startup

  • Explosive forces as the solver tries to separate interpenetrating bodies

  • Unpredictable behavior that makes the asset unusable in simulation

How to comply#

  • Review collision meshes for all links in the articulation.

  • Ensure collision geometry has appropriate clearance between non-adjacent links.

  • Use simplified collision approximations (convex hulls) that don’t interpenetrate.

  • Test the asset at the default pose to verify no collisions are detected.

Example#

Good: Collision meshes have clearance
┌─────┐     ┌─────┐     ┌─────┐
│Link1│─────│Link2│─────│Link3│
└─────┘     └─────┘     └─────┘
   ↑           ↑           ↑
 No overlap between Link1 and Link3

Bad: Non-adjacent collision meshes overlap
┌──┌─┐─────────────┐
│  │ │  Link1      │
│  └─│─────────┬───┘
│    │    ┌────┴────┐
│    │    │  Link2  │
│    │    └────┬────┘
│    └─────────┴──┐
│     Link3       │  ← Overlaps with Link1!
└─────────────────┘