Im having problems exporting a mesh into unreal. When I export the mesh to UT3 from XSI mod tool using the ActorX exporter the mesh gets "truncated" in areas and does not match the original.

I see people suggest solutions to this problem. They say its the smoothing groups. What I want to ask is: What are smoothing groups, how to "edit" them in XSI, and their effect on the model.

If someone can help me with this I would greatly appreciate it.