To overcome the topological constraints of non-uniform rational B-splines, T-splines have been proposed to define the freeform surfaces. The introduction of T-junctions and extraordinary points makes it possible to represent arbitrarily shaped models by a single T-spline surface. Whereas, the complexity and flexibility of topology structure bring difficulty in programming, which have caused a great obstacle for the development and application of T-spline technologies. So far, research literatures concerning T-spline data structures compatible with extraordinary points are very scarce. In this paper, an efficient data structure for calculation of unstructured T-spline surfaces is developed, by which any complex T-spline surface models can be easily and efficiently computed. Several unstructured T-spline surface models are calculated and visualized in our prototype system to verify the validity of the proposed method.

中文翻译：

---

用于计算非结构化T样条曲面的有效数据结构

为了克服非均匀有理B样条的拓扑约束，提出了T样条来定义自由曲面。T形结和非凡点的引入使得可以通过单个T样条曲面来表示任意形状的模型。然而，拓扑结构的复杂性和灵活性给编程带来了困难，这给T样条技术的发展和应用带来了极大的障碍。迄今为止，有关与非凡点兼容的T样条数据结构的研究文献非常稀少。在本文中，开发了一种用于计算非结构化T样条曲面的有效数据结构，通过该数据结构可以轻松有效地计算任何复杂的T样条曲面模型。