= Subdivision surface interrogation
Interrogation of a subdivision limit needs patch/topology navigation, refinement, limit evaluation and <derivatives> where they exist, with certified bounds and geometric error estimates. On regular patches one may use the corresponding spline representation. At <extraordinary subdivision vertices>, local <subdivision matrices> determine limit positions and tangents under the scheme's smoothness conditions. A <normal vector> may exist even when <second derivatives> and <Gaussian curvature> do not; finite refined polygons are approximations rather than exact limit queries.
Back to article page
