dirk

You can try (from the menu) assemblies>advanced>simplify assembly You can select all components which you want to have in 1 solid body. I have this almost every time, it doesn't seem to be a problem. If your part is not classified or anything I can try it for you.

I am an NX user. I have never had any problems loading stl files from NX. I use these settings: traingle tol 0.0025 adjacency tol 0.0125 auto normal gen on