How should I go about having objects in different "dimensions"

[Pindrought]

I have the possibility for entities/cameras to be assigned dimensions in my engine.
For example, I could have a cube at 0,0,0 in dimension 0 and a sphere at 0,0,0 in dimension 1.
The camera that is inside dimension 0 would only see the cube, and the camera in dimension 1 would only see the sphere.

What is the recommended way to handle something like this in Jolt since I would only want objects in the same dimension to collide with each other?

There are two methods I can think of, but i'm not sure if either of these are good/bad.

Method 1: Have some bits reserved in the layer for the dimension that layer is intended for and change the ShouldCollide implementations to compare the bitmask for the dimension. I wonder though if it will be a problem having a potentially large number of layers for performance?

Method 2: Each layer has its own physics system - The downside here seems like it would be memory usage.

Please let me know your thoughts on what the approach should be.

Thank you!

[jrouwe]

I think both methods are valid solutions and I can't really predict if one of them will be better than the other. If you pick method 1 and objects in different dimensions can never collide with each other then it is smart to give each dimension at least 2 broad phase trees (BroadPhaseLayer): 1 for static and 1 for dynamic. This minimizes the amount of work that the collision detection system needs to do as it can trivially disregard all other dimensions (since they're in different trees).