PolyNURBS
Quickly create free-form solid geometry that is smooth and continuous.
A PolyNURBS object represents geometry as a NURBS surface surrounded by a transparent polymesh cage. The shape of the PolyNURBS object is the result of the modifications made to the cage, which can be manipulated using the cage's faces, edges, and vertices. When you exit the PolyNURBS tool, the cage is hidden and you'll see the PolyNURBS object.
You can create PolyNURBS parts using the tools on the PolyNURBS ribbon.