what are nurbs and what can they be used for?

"NURBS, Non-Uniform Rational B-Splines, are mathematical representations of 3-D geometry that can accurately describe any shape from a simple 2-D line, circle, arc, or curve to the most complex 3-D organic free-form surface or solid. Because of their flexibility and accuracy, NURBS models can be used in any process from illustration and animation to manufacturing." http://www.rhino3d.com/ -Rob

Rob having provided precisley what Nurbs are also gave you a valuble link to go check out- Rhino the mighty and powerful NURBS modeler. McNeel let's you download Rhino and try it for If I recall 20 times before it becomes unusable. I still have 2 turns left.(Try sweep 2 rails if you download it :) I'm saving those turns for very well planned out models. Hand drawn with all things worked out on paper first. Rhino's limitation is it's rendering isn't the best however it imports into RayDream and other 3d programs in a variety of 3d formats including COB for Truespace. Blues-