Composing Bézier simplexes

This paper describes two algorithms for solving the following general problem: Given two polynomial maps f: Rn ↦ RN and S RN ↦ Rd in Bézier simplex form, find the composition map S = S ° f in Bézier simplex form (typically, n ≤ N ≤ d ≤ 3). One algorithm is more appropriate for machine implementation, while the other provides somewhat more geometric intuition. The composition algorithms can be applied to the following problems: evaluation, subdivision, and polynomial reparameterization of Bézier simplexes; joining Bézier curves with geometric continuity of arbitrary order; and the determination of the control nets of Bézier curves and triangular Bézier surface patches after they have undergone free-form deformations.