A Subdivision Scheme Based on Vertex Normals for Triangular Patches

Mao,Z., Ma,L., Zhao,M.

In order to achieve a smooth surface while rendering a triangle-based mesh, we need to eliminate the mismatch between the smoothness of the shading and the non-smoothness of the geometry that is particularly visible at silhouettes. To eliminate these artifacts, we substitute the geometry of a cubic triangular Bézier curved patch for a triangular flat geometry. Meanwhile a subdivision algorithm is proposed by using the degree elevation to approximate the triangular cubic Bézier patch only with little cost. The proposed algorithm can be processed without further knowledge of neighboring triangles, and can be operated as a process prior to a traditional rendering pipeline and required little change to existing authoring tools.