Try using the FBX format, it supports NURBS and Polys...
And it seems Rhino supports it.
https://download.mcneel.com/download.asp?id=FBX20060309
Also look at https://area.autodesk.com/index.php/ for any plugins for fbx.
Chris (formerly R@nSiD)
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Winner SM VFX Challenge 1
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