Collision Mesh limit

[TorQueMoD]

Hey all,

So it seems like the ok limit of collision primitives per model is sitting around 20. I have one mesh that's slightly more complex with 63 collision primitives. My question is, if I were to divide the mesh into 3 pieces with 21 collision primitives each, would it make a big performance difference? I mean, in every situation that the model is used, its going to require all 3 pieces so I figured if they're all one mesh with 63 primitives, it'd be the same thing as 3 x 21, but I'm not sure if the math translates the same as far as the engine sees it. Any insight on how the engine handles this would be greatly appreciated.

[BmB23]

Having less collision per object could help the physics engine optimize. I'm not sure of that though. Could also make zero difference to the optimization. It really depends how they did it.

[TorQueMoD]

Yeah, I'm not really sure if it makes that much of a difference. You'd think it would be total collision objects per scene rather than per model. I guess one way to look at it though would be that if the mesh is broken into 3 pieces, the engine would be able to cull the other meshes once they're not in view and remove the collision as well. Anyone else have any more insight into this?

[BmB23]

Typically you'd perform some sort of optimisation to only check things that actually have a potential to collide. It could optimize for every seperate primitive in which case it doesn't matter, or it could optimize per object in which case it does matter.

[TorQueMoD]

hmmm.... any Unreal Engine experts out there who could let us know how it works exactly with UDK?