in rhino you can round with variable adjustable radii:
http://www.vimeo.com/3275232here an overview video, from Matt Sedersberg, developer of Tsplines, my favorite rhino modeling plug- t splines:
http://www.vimeo.com/3612829this vidoe shows nice how you can edit rhino nurbs control points:
http://www.vimeo.com/4283768here s little video that shows how to get started with rhino3d paneling tools, custom shapes:
http://www.vimeo.com/4047815> oh yes, it does, and it is good:-)
the rhino3d OSX team does not simple a port, but a complete new rewrite on osx, to make rhino osx a native osx app.
recently they added python, the rhino OSX builds are regulary updated. each rhino owner can download and use them
some vimeo screencast about the interface(not absolute recent rhino osx verisons – 11 month old)
http://www.vimeo.com/4570149here a nice little rhino tutorial how to make a design ring:
http://www.vimeo.com/7793719