摘要
自由曲线离散终判条件的建立是其离散求交算法实现的关键.使用三次B样条曲线段的控制顶点和节点矢量对其二阶导矢进行估算,得到该曲线段高的估计值,从而确定其离散的终判条件.通过判断三次B样条曲线段控制顶点包围盒是否相交,确定两曲线交点可能存在的位置,然后依据离散终判条件,决定是否需要对曲线段运用插入节点算法进行中点离散,在此基础上建立其离散求交算法.
The foundation of the termination criterion for subdivision of free form curve is the key to realizing the discrete intersection algorithm. In this paper, the second derivative of cubic Bspline curve is estimated by its control vertices and node vectors, then the height of curve segment is obtained, and termination criterion for subdivision is determined. The possible positions of the intersection of two curves are identified by whether there are intersection points between the vertices boxes of curve segments. The middle point insertion method is adopted to discrete the curve, and the discrete intersection algorithm is founded based on the discrete condition.
出处
《武汉化工学院学报》
2005年第2期88-90,共3页
Journal of Wuhan Institute of Chemical Technology
基金
北京交通大学校基金项目(2003SM05)
