Adding simple primitives

[ValorZard]

2d: Circle, Box, Capsule 3d: Sphere, Cube/box, Capsule

Additionally, it would be nice if they could rotate and stuff, and if it would be possible for these shapes to merge. This would allow for a basic collision system to be formed.

[ValorZard]

Also, a way to display these collision primitive would be nice as well

[aevyrie]

I think visualization is better left to another crate, but it sounds like you are looking for the ability to raycast against these primitives to find the intersection?

Do you think parry would be a better fit for what you're trying to do? https://github.com/dimforge/parry

Is this what you're thinking for viz (animation)?: https://github.com/aevyrie/bevy_mod_bounding