Invisible Collision Mesh Has Purpose Guide#

Code

RB.010

Validator

Compatibility

Tags

Summary#

Invisible collision meshes must have their purpose attribute set to ‘guide’ to be properly excluded from rendering.

Why#

When collision meshes are meant to be invisible (used only for physics simulation, not rendering), they should have their purpose attribute set to guide. This ensures:

  • Renderers correctly exclude these meshes from final output

  • The collision geometry is clearly marked as non-renderable

  • Tools and pipelines can correctly identify physics-only geometry

How to comply#

  • Set the purpose attribute to guide on all collision meshes that should not be rendered.

  • Ensure collision-only geometry does not have purpose set to default or render.

Example#

def Mesh "CollisionMesh" (
    prepend apiSchemas = ["PhysicsCollisionAPI"]
)
{
    uniform token purpose = "guide"
    # Collision mesh geometry...
}

Good: Collision mesh with purpose = guide
┌────────────────────────┐
│ Mesh "CollisionMesh"   │
│   purpose = "guide"    │  ← Correctly marked as non-renderable
│   + PhysicsCollisionAPI│
└────────────────────────┘

Bad: Collision mesh with default purpose
┌────────────────────────┐
│ Mesh "CollisionMesh"   │
│   purpose = "default"  │  ← Will be rendered!
│   + PhysicsCollisionAPI│
└────────────────────────┘