中文摘要：

大型钢桥主要由板材和折弯板组成，其主体结构中有上万个高强度螺栓和零件，人工估算或根据孔轴对齐装配特征数目来确定螺栓数目及规格会造成统计的不准确，并且无法自动生成零件BOM。针对此问题，在三维CAD平台上，根据装配模型中组件之间的关系统计出零件的结构关系，并从零件的实体特征中得到零件的几何信息，通过坐标投影计算出各个零件的最小外包尺寸；同时，从三维模型的装配特征中过滤出螺栓连接的零件集合，并从装配体和零件的实体特征中获取螺栓孔的数量、直径和坐标信息，然后将螺栓孔的坐标或配合点的坐标投影到配合面的最小包容区域中，以确定螺栓孔所贯穿的零件；最后结合螺栓孔的几何信息和零件的几何信息计算出螺栓的数量、规格，并据此自动生成零件和螺栓BOM表。该方法已经被某桥梁设计研究所应用到桥梁设计中。

英文摘要：

Main structure of a steel bridge is mainly composed of plates and angle steels, which possesses ten thousands of high strength bolts and parts. Bolts information obtained through artificial estimation or shaft and hole assembly feature number is not accurate and BOM of parts and bolts can not be automatically generated. Focusing on this problem,an automatic generation method of BOM of bolts and parts based on three--dimension CAD system was proposed. Firstly, the structural relation of parts was obtained from the relation of components of assembly model and geometry informations of parts were obtained from solid features, so the minimum containment size can be computed by coor- dinate projection. Meanwhile, part sets connected by bolts were filtered from assembly features of the assembly model, then numbers, diameter and coordinates of bolt holes were obtained from solid fea- tures of the model. Secondly,coordinates of bolt holes and coordinate of the fitting point were projec- ted to the minimum contain region of the fitting face. According to the projection relation, the parts penetrated by the bolt holes were determined. Finally,the number and size of the bolts can be obtained based on geometric information of the bolt holes and geometric information of parts. The BOM of bolts and parts can be generated by the information. This method has been applied successfully to bridge and tower design.