NURBs modeling for Windows

Start with a sketch, drawing, physical model, or only an idea—Rhino provides the tools to accurately model your designs ready for rendering, animation, drafting, engineering, analysis, and manufacturing.

Rhino can create, edit, analyze, and translate NURBs curves, surfaces, and solids in Windows. There are no limits on complexity, degree, or size. Rhino also supports polygon meshes and point clouds.

See also http://www.rhino3d.com/

Or see http://en.wikipedia.org/wiki/Rhinoceros