公开(公告)号：WO1995006291A1

公开(公告)日：1995-03-02

申请号：PCT/US1994009573

申请日：1994-08-26

Applicant: APPLE COMPUTER, INC.

Inventor： APPLE COMPUTER, INC. ,  LOOP, Charles

IPC: G06F17/20

CPC classification number: G06T17/20

Abstract: A system and method for modeling smooth free-form shapes using B-splines over irregular meshes in a simple and efficient manner, generating aesthetically pleasing shapes is disclosed. This method provides a low degree parametric polynomial representation. As a result, techniques for surface-surface or ray-surface intersection is faster and more robust than possible with existing techniques. In accordance with the present invention, an input mesh M is initially simplified by isolating irregularities and constraining geometry. First, the input mesh M is subjected to general refinement, whereby a new mesh M is constructed, which in turn is subjected to constrained refinement, whereby another new mesh M is constructed. After the general and constrained refinement steps, the mesh M is broken up into a set of "quad-nets" corresponding to each of its vertices. Finally, these quad nets are used as local geometry, over which, 4 cubic Bézier triangles are constructed.

Abstract translation: 公开了一种用简单而有效的方式使用B样条对不规则网格进行平滑自由形状建模的系统和方法，从而产生美观的形状。 该方法提供了低度参数多项式表示。 因此，与现有技术相比，表面或光线表面交叉的技术更快，更可靠。 根据本发明，最初通过隔离凹凸和约束几何来简化输入网格M 0。 首先，对输入网格M 0进行一般的细化处理，由此构造新的网格M 1，其进而受到限制的细化，由此构造另一个新的网格M 2。 在一般和约束的细化步骤之后，网格M 2被分解成对应于其每个顶点的一组“四网”。 最后，这些四边形网络被用作局部几何体，在其上构造了4个立方体贝塞尔三角形。