Physics Simulation Spaces

[marsmaantje]

Is your feature request related to a problem? Please describe.

There are many situations where you want certain elements of the physics simulation to only interact with a specific subset of others. examples:

• A paintbrush only interacting with its canvas or "paintable" surfaces.
• Projectiles only interacting with users or damageable objects.
• In the future with rigidbodies, only have the balls on a pool table interact with each other and the table.
• A raycast only checking for specific colliders you want it to collide with. (ignoring users perhaps)

Describe the solution you'd like

The ability to assign colliders to one or more physics simulation spaces or layers. This might show up as a list entry on the collider allowing you to reference specific simulation spaces, or the reverse, where you assign specific colliders to a simulation space present in the world.

Describe alternatives you've considered

A rudimentary version of this already exists in the separation of haptic and normal colliders, so users could (ab)use the haptic layer as a secondary simulation space. Alternatively you can filter collision events in ProtoFlux

Additional Context

Requested by: Elektrospy, marsmaantje, Zyzyl

[JackTheFoxOtter]

I would like this. This could allow the feet IK raycast to exclude certain layers / "tags", allowing you to mark raycast colliders as "ground", or rather "not ground". Could stop gizmos from freaking out avatars when selecting them, among other things.