三次参数曲线段的形状控制

本文利用三次参数曲线段ｒ（ｔ）极值，点的多数值ｔ．和相对极大值ｓ来控制ｒ（ｔ）的形状，论证了用这两个参数能直观地确定ｒ（ｔ）的极值点位置和个数，拐点、奇点分布，两端曲率符号等重要的形状特征，并给出相应的确定方法．

Shape Controlling of Cubic Parametric Curve Segments

In this paper. two parameters in respect to the extreme value points of cubic parametric curve segment r (t) are used to control the shape of r(t) . The possibility and directness of using these two parameters to determine the essential shape characters of r (t) are demonstrated and the relevant methods are given.