Rigidbody objects not colliding.

Can someone provide more details around this? I have a need for mesh on mesh collision. I have some very large objects that I need to get right up on and a box collider wont work. $$anonymous$$aybe I can use a box or capsule for the smaller object co$$anonymous$$g up on the larger one, but I suspect I'll have some situations where 2 large vehicles are getting up on each other and a crude box to box wont look right?

2 points:

1. what's this that mesh on mesh won't collide? I'm experiencing this but I don't understand why? Seems like a very odd limitation to me.

2. when I was writing my own engine I'd use a box or sphere collision for a crude check and then perform a more detailed mesh check only if the box/sphere check shows a collision. Doesn't Unity support something similar, and if so what's the best way to set it up?

thanks

1. Because it's a very expensive operation. As I mentioned in my answer, you can use convex mesh colliders, but those have limitations (such as, well, being convex, also a max of 256 polys).

2. Yes, that's what Unity does.

Thanks Eric.

Relative to question 2, does this happen automatically? In other words, I don't need to add two separate colliders, right? I suspect internally it's going to do a sphere distance check then apply whatever collider you've chosen for the detailed collision, or do you need to somehow specify how you want it to behave?

Yes, certainly it's automatic.