为了探索CAD/CAM领域中的特征造型关键技术,研发一个特征造型系统。该系统分别以ACIS和HOOPS为几何造型引擎和渲染引擎,能够实现常用特征的创建、特征历史的管理、基本约束的管理和特征模型与几何模型的存取等功能,并且支持一些自由曲面特征造型以及参数化设计。为了维护用户的隐含设计意图,系统采用了一种新的拓扑元素命名与辨识机制。最后,给出了使用该系统进行特征建模、自由曲面特征参数化设计以及设计意图有效维护等实例,验证了本系统的可行性和有效性。
A feature modelling system is studied and developed for exploring the key technique of feature modelling in CAD/CAM.This system uses ACIS as the geometric modeller and HOOPS as the render respectively.Most of basic functions supported in prominent feature modelling system are realised in this system,such as the creation of common features,the management of feature history,the management of basic constraints and the access of feature models and geometric models.Moreover,some freeform surface features modelling and parametric design are supported by the system as well.A new mechanism which is used to name and identify topological entities is used in the system for maintaining users' implied design intent.The system has been tested by a number of test examples,such as feature modelling,parametric design for freeform surface feature,and users' implied design intent maintaining,which shows that the system is feasible and effective.