From 3D Studio Max help file; NURBS (Non-Uniform Rational B-Splines) are a technique for modeling 3D curves and surfaces interactively. The term NURBS stands for Non-Uniform Rational B-Splines. Specifically: Non-Uniform means that the extent of a control vertex's influence can vary. This is useful when modeling irregular surfaces. Rational means that the equation used to represent the curve or surface is expressed as a ratio of two polynomials, rather than a single summed polynomial. The rational equation provides a better model of some important curves and surfaces, especially conic sections, cones, spheres, and so on. A B-spline (for basis spline) is a way to construct a curve that is interpolated between three or more points. LOL...you asked! Hope this is some help anyway. BTW, thanks Catlin!