平面多边形凹凸性的算法研究

首先介绍目前计算机辅助设计应用系统中判断平面多边形凹凸性的常用算法，鉴于它具有占较多的ＣＰＵ时间、循环复杂、而且次数多，从而提出了一种判断平面多边形凹凸性的新方法，该算法逐点进行凹凸性判断，算法简单，循环少，占用的ＣＰＵ时间也大大减少，该算法对Ｃｏｏｎｓ，Ｂｅｚｉｅｒ，Ｂ－ｓｐｌｉｎｅ样条曲线特征多边形的凹凸性判断具有重要的意义。

Study on Operation of Plane Polygon Convexity and Concave

A common operation, which decides whether a plane polygon is convexor concave in some CAD system, is introduced in this paper. But it would require moreCPU time and have a complex calculating cycle. A new operation, which is easy to decide the concave or concave of a polygon, is studied. The operation decides the convexor concave one point by ones. The operation is easy, has less cycle and requireslessCPU time. Esp, it would play an important role in deciding the the convex of characteristic polygon of Bezier,B-Spline curve.