re: Sycode plugin - I'm not really sure if the Sycode 3DM import plugin for AutoCAD will read NURBS objects from the 3DM file (which is what you need) or only polygon mesh objects from the 3DM file. It seems to mention the latter only here.

If that's the case you may need to use the IGES importer instead, I'm not quite sure.

- Michael

Thank you Michael, I will try to combine everything using 3ds and obj inside my rendering apps for now...it seems the only reliable solution.