Surface intersection using a ne arithmetic

We describe a variant of a domain decomposi tion method proposed by Gleicher and Kass for in tersecting and trimming parametric surfaces In stead of using interval arithmetic to guide the de composition the variant described here uses a ne arithmetic a tool recently proposed for range analy sis A ne arithmetic is similar to standard interval arithmetic but takes into account correlations be tween operands and sub formulas generally provid ing much tighter bounds for the computed quantities As a consequence the quadtree domain decomposi tions are much smaller and the intersection algorithm runs faster