Abstract: A class of modifiable rational Bezier curves with n+1 control points and a parameter l are presented.These curves preserves the shape of the control polygon better than original Bézier curves.By varying the values of the parameter l,the shape of the curves can be modified and the curves approximate globally to the control polygon as l increases infinitely.

Key words: rational Bé, zier curves, approximate uniformly, basis function, modifiable