I'm not sure if this helps or not... I have done quite a few scan to cad models. there is a step that need to be done before you get it into a CAD program. I would be sent the scanned model (they are very heavy) I would bring them into Blender and hand retopolize them with as low a poly count as I can get (the models were usually bottles with threads, I wouldn't do the threads in blender) I would use shrinkwrap and sub-d as an aid. Once that portion was done (all quads) I could bring them into Moi and create threads or what ever needed to be precise. It was a pretty quick activity once one got going.
cheers,
Val