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The B-spline and NURBS families are the spline technologies that have become the standard for geometric modeling in CAD and computer graphics (Cohen et al. 1980, 2001; Piegl and Tiller 1997; Rogers 2000; Farin 2002) over the years. The NURBS functions lend themselves to an exact representation of many shapes used in engineering, such as conical sections (circles, cylinders, spheres, ellipsoids, etc.). NURBS are a generalization of B-splines: they can be viewed as rational projections of B-splines that are piecewise polynomials. Therefore, they possess many of the properties of B-splines, the most interesting one being their possible increased smoothness, thus implying models with few degrees of freedom. Since NURBS are based on B-splines, we start the presentation below with B-splines.