Hi Micha, the other thing I don't quite understand is why you are so intent on loading the mesh data back into Rhino. Rhino has some issues with handling mesh data in general - there are various restrictions like you can't use n-gons, and you can't have welded mesh points that have joined vertices but separate UVs and normals for each face.

Most people who are "mesh only" users are generating meshes to go into some more full featured polygon modeling program like Modo or Cinema4D. For these programs using OBJ or LWO format is the way to go - these formats handle mesh structures that are not allowed in 3DM mesh data (n-gons and welding).

Why are you so intent on trying to use Rhino as a mesh modeling program when it is not really a particularly good thing to use it for?

- Michael