Cooking a mesh

Ok say I have a mesh blah.mesh that from 3ds max using the lexi exporter.. what do i need to do to cook that mess to get the physics model for whatever weird shape the over all model it might be?

Also are there limits on detail of models when cooking?

Depends on the type of mesh.

But in 0.9, you can throw an Ogre Mesh into NxOgre and it'll convert it on the fly for you through what ever type of shape you want it to be used in.