基于面向对象的参数化设计模型及其实现

OBJECT ORIENTED PARAMETRIC DESIGN MODEL AND ITS IMPLEMENTATION

介绍一个基于面向对象的参数化设计模型及其具体实现．此模型将几何元素（如线段、圆弧等）抽象为具有一些共同属性与操作的几何对象，利用面向对象的继承机制，可以把几何元素分成不同的抽象层次加以表达．基于此建立起来的设计模型具有良好的语义性、柔性、可扩充性和可操作性．采用正向与反向相结合的搜索和推理策略，可以解决二维和二维半几何设计中局部具有隐含约束而整体存在多个解的问题．

In this paper, an object oriented parametric design model and its implementation are introduced. The geometric elements in the design model, such as line, arc, etc, are extracted as an abstract geometric object with common attributes and operations and are represented in a hierarchy according to the inheritance mechanism in the object oriented method. As a result, the model is semantic, highly flexible, fully expandable and exceptionally operational. Both forward and reverse searching and reasoning methods are used to obtain final solution of the parametric design model. This approach has been successfully applied to 2D and 2.5D geometric design problems, in which multiple solutions are found with implicit geometric constraints. A parametric design system based on the design model has been developed through C ++ in PC environment.