高级检索

基于平面六边形割边的细分曲面

Subdivision Surfaces Based on Planar Hexagon Edge-Cutting

  • 摘要: 将割角细分曲线方法推广至割边细分曲面生成目前尚未得到解决,为此,提出一种逐次割边的细分曲面方法。通过重复割去网格的所有边(二面角),对于凸多面体初始网格,能够细分生成保凸、面片均为平面多边形、光滑且内切于初始多面体的曲面,是割角细分曲线方法的一种新推广。在给出割边思路的基础上,首先确定割边点初值参数的取值范围,以避免过割边现象;随后给出割边点选择调整算法,在割边点参数满足取值范围的条件下,使割边平行于对应的网格边;进而给出新顶点的计算公式;最后给出该方法生成自然边界和常规边界两种边界处理方式。对正四面体、立方体及其变体进行细分实验的结果表明,与经典的插值保凸细分方法相比,所提方法除具备相同的主要性质外,在内切性质以及曲面所含部分直纹面区域边界的光滑性等方面具有明显优势。

     

    Abstract: It is difficult to extend corner-cutting subdivision curve methods to edge-cutting subdivision surface gen-eration. In this paper, we propose a planar hexagonal edge-cutting subdivision scheme which can generate interpolatory and convexity preserving inscribed smooth surfaces for convex polyhedral initial meshes through only edge-cutting by planes. The method is a new extension of the corner-cutting subdivision curves. First, the conditions of initial parameter for edge-cutting are given to avoid over cutting. Next, the method for adjusting edge-cutting points is presented for making the new edge parallel to the old edge. Then, the formulae for calculating new vertices are obtained. After that, two methods for generating a nat-ural boundary and a normal boundary are also given. The initial meshes of numerical examples include regular tetrahedron, cube and its variants. The results show that our edge-cutting method possesses the same main properties as the interpolatory convexity preserving subdivision and has some advantages over the latter. 

     

/

返回文章
返回