Poly's are easier to handle...while working with nurbs is more like "chewing-gum" ;O)

For Nurbs-Surfaces you need less Isoparms and CV's to get a round look whereas polys are only direct connections between the vertices. SubdivisionSurfaces have both...the advantages of poly-modelling (with extruding aso) and the perfect roundness of Nurbs-Surfaces.

Nurbs Surfaces are usually faster to render than poly one's....When rendering with Renderman, Nubs are always the better choice, because renderman doesn't need to tesselate the nurbs surface. It can handle them as they are (that's one reason why they use nurbs-patches for production). I've heard that SubD's are even faster to render than Nurbs-Surfaces....that's why they have changed the models from final fantasy later on from Nurbs to Subd's.

Nurbs are not more expensive than Polys..you can't say that.,...remember Animation master ?? A complete Spline-Patch Program as i know.

Hope this helps

b u l l e t