What happend to mesh after applying lightmap?

[_Neo]

Basically, I use newton dynamics for physics simulation.And I have to extract vertices and vector to create Newton Collison object,
but the problem is, the mesh's vertices cannot be extracted correctly after the light map is applied in the map.
So I just wondering what happened to mesh after lightmap is used and how to get correct vertices in this condition?

[hybrid]

You probably use the base SMesh, while lightmapped meshes have special vertex types. You have to do the casts properly.