ABSTRACT
Once the general theory and the general algorithms are known, they must be interpreted and made practical for use in design. While the possible spaces of curves are very general, there is no theoretical method for determining which ones are feasible in particular design situations. For this reason we discuss each of the criteria for specifying spline curves and con sider their effects on the resulting curves. These issues include the effect of knot vector selection, including end conditions and multiple knots, control polygon specification, and degree specification. We also discuss the interrelationship of these criteria. Multiple vertices are sometimes used to cause interpolation at the end of the curve, but the curve obtained is not the same curve as the curve obtained with an open knot vector. We discuss and compare the resulting curves.
