Practical shadowing test for PO integral on trimmed NURBS surfaces

A practical shadowing test technique for the trimmed NURBS surface (TNS) is presented in this work. By employing an efficient Bezier patch classification algorithm, a two-level hierarchical space partitioning volume (HSPV) is built for the TNS, where the leaves of the HSPV that contains trimmed off part of the original surface are marked out, making sure the shadowing test occurs on the effective part of the original surface. The numerical example demonstrates the effectiveness of the proposed method.