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    基于工程图的二次曲面体重建

    Reconstruction of Quadric Surface Solids from Engineering Drawings

    • 摘要: 针对基于工程图的曲面体重建 ,在现有的基于边界表示模型 (B reporiented)的重建方法中 ,提出了“线面交点计数判别法”来判断曲面上基环之间的位置关系 ,即曲面上顶点和多边形的包含关系 ,建立各表面上的基环位置关系树 ,并据此构造实体模型的候选面片 最后 ,根据二维流形 (2 manifolds)的性质和莫比乌斯法则 (M biusrule)以及正投影规律从候选面片中提取面序列和确定性面序列 ,将符合条件的面片和面序列装配成实体 这些方法的提出与应用 ,将传统的处理对象由平面拓展到二次曲面 ,从而扩大了形体的重建覆盖域 ,同时减少了候选面片的组合判定次数 ,提高了重建效率

       

      Abstract: An algorithm is presented for automatically creating a quadric surface model from orthographic views using the B-rep oriented approach. An edge-face-intersecting approach is developed and employed to determine the containment relationship between any two fundamental loops in each quadratic surface. A relationship-tree is then established by completing the containment test for those fundamental loops,and all candidate faces in that surface are therefore constructed by searching for the external loops and internal loops according to the relationship-tree. Further,all valid candidate faces can be assembled to compose the ultimate objects based on the characteristic of orthographic projection,the definitions and properties of 2-manifolds,and Mbius rule as well. The method not only is an important extension to the previous published algorithms for reconstructing 3D curvilinear objects from orthographic views,but also reduces the search space and improves the efficiency of the algorithm consequently by searching for face-sequences and identifying certain-face-sequences.

       

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