支持自顶向下设计的产品功能建模技术

自顶向下的设计模式符合一般的设计规律，而以几何建模技术为主的各种CAD系统难以真正地对这一过程提供支持。本文介绍了一种基于功能单元和功能特征的产品功能模型，它能够表达产品的功能结构和功能关系，并建立对零件形状特征的功能约束。功能建模系统同基于特征的产品建模系统相连接，能够实现自顶向下的产品设计。

Function Modelling Supporting Top-Down Design Process

The top-down design process conforms to the general design principle, however, those CAD system withonly geometry model can not really support it. A function model based on functional unit and function feature isintroduced in the paper, which can represent the functional structure and relationship of product, and generatefunctional constr aints to form features. Together with feature-based modelling system, the function model can supportthe top-down design process.