层次约束结构的虚拟装配建模技术

Virtual assembly modeling based on hierarchical and constrained structure

为了解决虚拟环境下装配建模在信息完备性和模型复杂性等方面的问题,提出了一种基于层次约束结构的虚拟装配模型.该模型分为产品层、部件层、零件层、特征层、几何面层和面片层来表达,不同层元素之间存在层次映射关系,同一层元素之间存在约束关系.通过CAD系统和虚拟装配系统之间的数据转换,实现了虚拟装配模型的生成算法,并给出了根据虚拟装配模型生成的虚拟装配场景图的结构.基于层次约束结构的虚拟装配模型具有信息表达完备,信息集成度高,满足实时性要求等优点,同时还能与CAD系统和虚拟装配场景图实现集成.实例验证了虚拟装配建模的有效性.

In order to solve the problems such as information completeness and model complexness of assembly modeling in virtual environment, a hierarchical and constraint-based virtual assembly model is proposed in this paper. This virtual assembly model includes product layer, component layer, part layer, feature layer, surface layer and polygon layer, the hierarchical mapping relationships are existed among the elements in different layers, and the constraint relationships are existed among the elements in the same layer. Based on data transformation from CAD to virtual reality system, the generation algorithm of the virtual assembly model is realized, and the structure of virtual assembly scene graph is given. The hierarchical and constraint-based virtual assembly model has high integration of information and can satisfy the real-time demands, and it is convenient to be integrated with CAD systems and scene graph. The examples are given to demonstrate the effectiveness of the proposed virtual assembly as well.