I have a question for you.
3DS file use a single index for verticies, normal and texcoords. So when you change UVW Map (Spherical, Plane, ecc...) 3DS change index to change texcoords.
I have some trouble with this. I have implemented an algorimth that reasearch the object's edges to extrude geometry (stencil shadow). To do this I need that any superficies is closed: any edges is shared by two triangles (or faces). With default plane UVW map I have no trouble, but with any other UVW Map my algorith don't find two triangles for any edges. Why ? How Can I Solve This Problem ?