关于三次参数曲线的形状控制

On shape control of the parametric cubic curve segment

讨论了平面三次参数曲线在端点出现拐点、二重点、尖点的情形 同时 。

The main resul;t o this paper is detailed disuss the parametric cubic curve segment at the end points oceur infection point,multiple point and cusp situation.In the same time,we discuss the problem in detail for some special Cases,for instance,tangent veetors at ends are parallel.