Hi Felix, well it was worth a try!

Polygons and NURBS files are fairly different in the way that they are set up to work, so it's not very common to go back and forth both directions between them all the time.

Starting with NURBS and going to polygons works well, but starting with polygons and then going to NURBS is not a very natural thing.

The comparison I usually make is like apples and applesauce. If you start with apples you can go to applesauce no problem by smashing up the apples. However, if you start with applesauce it is difficult to reconstruct apples back from that.

For the most part you should usually plan that if you need to work with polygon type data that you will be working with that in a polygon-focused modeling program and not in MoI.

- Michael