中文摘要：

在对钣金件特征研究和“零厚度”假设的基础上，提出一种钣金件自动展开新方法。对钣金件进行特征分类，基于特征设计进行钣金件特征造型，并通过特征树的形式存储特征之间的关系，最后对特征树进行中序遍历得到钣金件的展开图。并将上述方法应用在SMCAD（Sheet—Metal CAD）系统中。结果表明，该方法能方便快捷的实现钣金件自动展开，并使钣金件设计和展开摆脱了对三维平台的依赖，展开过程更为简洁。

英文摘要：

Based on the study of features of sheet metal parts and zero thickness hypothesis, a new method of sheet metal automatic unfolding is proposed. First, the features of sheet metal are defined and classified, then the approach of feature-based design perform feature modeling and the approach offeature tree is used to store the relation offeatures. Finally, the automatic unfolding of sheet metal parts based on the in-order traversing feature binary tree is implemented. This new method are applied in the SMCAD （CAD system of sheet metal parts） system, the experimental results show that the sheet metal parts can be easily unfolding without the support of 3-D solid modeling platform.