i have the same problem, so i “bake” the nurbs into meshe before use Datasmith, in ue 4.24.3. Another very interesting export option would be the possibility of joining the objects by layer or by materials something similar to what is done in twinmotion, it would be a pleasant possibility to do an export from twinmotion to ue4, this would solve half of the export problems already that the sync option between rhino and twinmotion works relatively well. regards