Hi Michael and Max,

i just recently discovered an open source solution, based on the FreeShip
software, available at Github, which allows one more or less to convert a
subd mesh to a NURBS model. While this solution somehow works, the
final model is however not stitched and there are some areas which needs
to be reworked. Anyways i thought to show this to you, so that maybe it
could lead in the future to an easy? subd to NURBS solution for MoI.
Compared to Max's solution this one has fewer patches and not like for
every polygon a patch.

https://blenderartists.org/forum/showthread.php?412430-From-Blender-Subdivision-To-N-U-R-B-S-(IGES)-for-free

Best regards
Stefan