Patching Non-Uniform Extraordinary Points with Sharp Features

Abstract

Extending the non-uniform rational B-spline (NURBS) representation to arbitrary topology is one of the most important steps to define the iso-geometric analysis (IGA) suitable geometry. The approach needs to be NURBS-compatible and can handle non-uniform knot intervals. To achieve this goal, we present a novel patching solution which define one Bézier patch for each non-zero knot interval control grid face. The construction can reproduce the bi-cubic NURBS in the regular face and define bi-quintic Bézier patches for irregular faces. The method can also support non-uniform sharp features along the extraordinary points. Experimental results demonstrate that the new surfaces can improve the surface quality for non-uniform parameterization.