After many trials for me there isn't better way to convert a #Blender's #SubD to #Nurbs #IGES. 
Using #FreeShip and #meshconv, that is the method to have perfect surfaces based on the initial topology that allows you to have total control over the final result. #b3d #blender3d
Below a tips by me on BA
https://blenderartists.org/t/from-blender-subdivision-to-n-u-r-b-s-iges-for-free/