Untrimming: Precise conversion of trimmed-surfaces to tensor-product surfaces

Trimmed B-spline surfaces are very common in the geometric computer aided design (CAD) community due to their capability to represent complex shapes that cannot be modeled with ease using tensor product Bspline and NURBs surfaces. However, in many cases, handling trimmed-surfaces is far more complex than tensor-product (non-trimmed) surfaces. Many algorithms that operate on tensor-product surfaces, such as algorithms toward rendering, analysis and manufacturing, need to be specially adapted to consider the trimming domains. Frequently, these special adaptations result in lack of accuracy and elevated complexity.