Hi, I guess the best way to translate SW assemblies to UG (NX2) is via parasolid (bin or asc). Although I define the parasolid option not to flatten assembly hirarchy (the checkbox is unchecked), the assembly is imported to UG without any tree structure (all parts are children of the root parent). Although this is not a UG group, maybe someone knows the secret how to keep original structure in UG? Thx, Steph.