FWIW, I really like the Autodesk 123D program. I don't see where it exports STEP, but SAT works fine. I was able to quickly cobble together a basic widget in short order:


Create the basic shape in MoI


Export as SAT to 123D, fillet there using dynamic filleting, and bring back as imported SAT. Next add some kitbash:


Exports as OBJ to KeyShot and Voilà

@Chipp

<<I don't see where it exports STEP, but SAT works fine.

Don't know what format is the best for you? :)
But your results seems yet convincing!

PS Free version is of course for no commercial use! ;)

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When you press it you have that! :) (Windows user)

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Interesting. Mine is different (I'm using free commercial version downloaded from Mac App Store)

@Chipp

Maybe an "advantage" or more "disadvantage"of the Mac World! ;)
In any case one format is yet sufficient for Nurbs world! :)