Truncated hierarchical CatmullClark subdivision with local refinement
In this paper we present a new method termed Truncated Hierarchical CatmullClark Subdivision  (THCCS), which generalizes truncated hierarchical B-splines to control grids of arbitrary topology. THCCS basis functions satisfy partition of unity, are linearly independent, and are locally refinable. THCCS also preserves geometry during adaptive h h -refinement and thus inherits the surface continuity of CatmullClark subdivision, namely C2 C 2 -continuous everywhere except at the local region surrounding extraordinary nodes, where the surface continuity is C1 C 1 . Adaptive isogeometric analysis is performed with THCCS basis functions on a benchmark problem with extraordinary nodes. Local refinement on complex surfaces is also studied to show potential wide application of the proposed method.
catmullclark subdivision local refinement hierarchical b-splines extraordinary nodes isogeometric analysis truncation mechanism