Abstract: In order to more effectively design the shapes of automobile headlamps, a car headlight contour design method was presented herein based on cubic quasi-Bézier curves with shape parameters. Firstly,the smooth connection conditions of piecewise cubic quasi-Bézier curve were studied. Then the car headlight contour curves were constructed using cubic quasi-Bézier spline curves. Besides,the adjustment methods of the contour curve shapes were proposed including the shapes of contour edges and corners. Finally,lights headlight contour model was obtained according to the orthographic projection curves. The contour curves might be flexibly adjusted by changing the values of shape parameters and the positions of control points. Compared with the conventional method,the curve used in this method has a lower degree and the calculation is easier. Numerical examples show that the method proposed herein is simple,effective and ease to complete interaction designs of shapes.

Key words: headlamp contour, cubic quasi-Bézier curve, geometric continuity, shape control

摘要： 为了更加有效地设计汽车车灯的形状,提出一种基于含形状参数的三次拟Bézier曲线的汽车车灯轮廓线设计方法。研究了分段三次拟Bézier曲线的光滑拼接条件;利用三次拟Bézier样条曲线构造了汽车车灯投影轮廓线,并分析了轮廓曲线大调与微调的方法,包括轮廓边线和边角的调整;最后根据车灯正投影曲线得到了车灯轮廓模型。通过调整形状参数的取值和控制顶点的位置,可以根据需要灵活地控制轮廓线的形状。与现有方法相比,该方法使用的曲线具有更低的次数,计算更简便。数值实例表明，该方法简单有效，便于形状的交互设计。

关键词: 车灯轮廓；三次拟Bé, zier曲线；几何连续；形状控制