> but sadly I think the changes will need to come from their end.

Yes, this is probably true. If they don't have the type of mesh structure where two adjacent faces can share the same vertex, but let each face have its own unique vertex normal, then that's going to prevent it from being able to read in .obj files in their full fidelity. MoI won't produce .obj files with this type of structure quite yet, but it will once the next phase of handling the welding is done.

But there is still some additional stuff that I can do that might help - I can also define smoothing groups inside the .obj file, and if they process those then I can probably get it set up a lot better than when you try to do a merge with break angles.

- Michael