collisionhull / collisionmesh

[gamecreator]

I was wondering simply what the limitations are of creating shapes like this in a 3D modeling program. In other words, how complex can they be?. Can they be a single plus shape (+) or will that need to be made out of two boxes (or more, if they can't overlap)? How about a torus knot?

 

Maybe it's easier to ask if the collisionhull/collisionmesh shapes must be convex as well, like the convex shape examples in the tutorial.

 

(I am aware that they don't work with animated models though.)

[Josh]

If you want a dynamic concave shape, build it out of multiple convex shapes. If you just want static geometry (an object that can be collided against but can't itself move) then the collision mesh is fine. Simpler geometry is always better because it's faster to calculate. Physics shapes can be very rough approximations of the visible geometry..

[gamecreator]

Thanks. Are you saying then that collision meshes can be non-convex?

 

I was just thinking of things like rotating gears like in the below mockup and how I would theoretically pull them off, though I'm not working on my Summer Games entry any more for the time being.

 

[Josh]

I would make the round part a cylinder and make a box for each of the teeth.