Handling Extraordinary Nodes with Weighted T-spline Basis Functions

To generate analysis-suitable T-splines for arbitrary topologies, in this paper we introduce a new method to deal with extraordinary nodes in the T-mesh. Knot interval duplication method is used to extract knot vectors for the extraordinary nodes and spoke nodes. From defined bicubic weighted T-spline basis functions, the extracted Bézier coefficients are modified to obtain a gap-free T-spline surface. The boundaries shared by the first-ring neighboring Bézier elements are C0-continuous. Then we use biquartic Bézier basis functions with optimized coefficients to increase the surface continuity to G1. Comparison with other methods shows that our method generates T-spline surfaces with better surface continuity for analysis.