Giger, Christine2015-10-052015-10-0519891017-4656https://doi.org/10.2312/egtp.19891009With regard to ray tracing algorithms for polynomial tensor product surfaces, the most timecritical step is to find an intersection point of a ray and a surface. In this case it proves to be very difficult to decide whether numerical methods will converge to the correct solution. In this paper we present a new method based on numerical algorithms which is suitable to solve the intersection problem. We mention how to force correct convergence and give some information about techniques to speed up the algorithm.10.2312/egtp.19891009