设计过程中设计意图维护和拓扑元素命名

Design Intent Maintenance and Topological Entities Naming in Design Process

拓扑元素的命名和辨识是基于历史的参数化特征造型中的一个关键问题,其实质是维护设计过程中隐含的设计意图.通过分析设计过程与拓扑元素命名的内在关系,面向隐含设计意图捕获,给出了设计过程中拓扑元素变动类型及其被引用元素辨识要求;提出了面的有向等参线概念和基于有向等参线的面面连接关系,以面为核心,综合拓扑元素的局部拓扑信息和几何特性进行拓扑元素命名;将拓扑元素相邻面分成活化面集和非活化面集,基于设计变动连续性观察,将隐含设计意图通过拓扑元素相关面集的子集关系表达出来,提出了拓扑元素辨识的子集关系原则.实验验证表明,文中方法能够更有效地处理拓扑结构发生变化的情况.

One of the fundamental issues with history-based parametric feature modeling is how to effectively name and identify referenced topological entities. And its key point is how to maintain implied design intents during design process. The interrelationship between design process and topological entities is analyzed, and the topological entities＇ change types and identification required for capturing design intents are given. Two concepts, the directed isoparametric lines （DIL） on a surface and the face-face relationships （FFR） based on DIL, are introduced. By using the local topological information and geometrical information, a face-based topological entities naming approach is proposed, which provides more design intent information for topological entities identifying. The adjacent faces of a topological entity are divided into active face set and non-active set. Based on the continuity of the design variation, the implied design intents are expressed in terms of sub-set relationship between related face sets. A sub-set relationship principle for identifying topological entities is put forward. The proposed approach has been tested by a number of test examples, which show the approach can deal with the situations with topological changes more effectively.