中文摘要：

定义关联两曲线间的夹角和由3条关联曲线确定二次曲面，提出适用于曲面的回路搜索最小转角法，且利用它并辅以矢量混合积验证搜索曲面上最小回路的方法．实现从线框模型中选择任意一条曲线就能够搜索到包含它的所有潜在表面回路，突破以往回路搜索方法中只能从某方向极值点开始的束缚，为线框模型表面识别中将含曲线表面与不含曲线表面分治识别奠定基础．算法可处理含有任意位置的二次曲表面的线框模型，并能较准确地判别二次曲面的类型．

英文摘要：

The angle between two connected curves on same quadric is defined and two minimum internal angle algorithms（ MIA_cw and MIA_ccw） that can be applied to quadric surfaces are proposed. When a circle is searched by MIA_cw or MIA_ccw, the vector mixed product is employed to verify whether the circle is a candidate surface or not. In the proposed method, no matter which curved edge of wire-frame model is chosen, the candidate surface containing it can be obtained. Thus, it removes the restriction on the start edge in searching candidate surface in existing methods. The candidate surface with curves is separated from those without curves by the proposed method and different algorithms can be used for these two kinds of candidate surfaces. And it requires less time than the one using one algorithm to search all candidate surfaces （ including quadric surface and plane surface）. Furthermore, the proposed method can deal with the 3D wire-frame models with no restriction on the axis of the quadric surface and identify the type of the quadric.