Abstract: According to the special requirements and characteristics of product model in virtual environment, the conception of product toleranced model was proposed. After analyzing the requirements of tolerance information in Virtual Environment (VE), it was pointed out that not only basic information but also dynamic behavior information of tolerance were needed. Based on the characteristics of triangle-surface model in VE, a new multi-layer-structure of Product Double Coupled Toleranced Model(PDCTM) oriented to VE was proposed. Combined with product attribute information modeling, the problem of product toleranced modeling in VE was solved. The realization methods of PDCTM, especially the construction of geometrical model, acquisition of attribute information and mapping methods among different layers of the model, were discussed in detail. The application methods of this model were also put forward through discussing the functions of dynamic behavior of tolerance in virtual assembly, visualization technologies of tolerance and precision, as well as the design feedback of tolerance.

Key words: tolerance modeling, virtual environment, product double coupled toleranced model

摘要： 从虚拟环境下产品模型的特点和特殊要求出发，提出了产品公差模型的概念，分析了虚拟环境对公差信息的需求，指出除基本信息外，还需要提供公差的动态行为信息。根据虚拟环境下面片模型的特点，提出了一种面向虚拟环境的多层次结构的产品双耦合公差模型，并结合产品属性信息建模，解决了虚拟环境下产品公差模型的构建问题。从几何模型的构建、属性信息的获取、不同层之间的映射技术等方面，系统地论述了该模型的具体实现方法，并结合公差动态行为信息在虚拟装配中的作用、公差和精度的可视化显示、公差的设计反馈等技术论述了该模型的具体应用方法。

关键词: 公差建模, 虚拟环境, 产品双耦合公差模型