Feature Modeling Based on Topological and Geometrical Constraints for Realizing Designer's Intent

目前，已实现了具有参数化建模功能的CAD系统。然而，由于设计师的意图在工程图纸中表现为约束和制造信息，而不是直接表现在产品模型中，而是表现为命令的历史和形状的尺寸值，因此无法实现高效的产品开发。因此，我们的研究目标是开发利用拓扑和几何约束以及属性信息对设计师意图的符号化表示，根据设计师的直接指示进行有效的参数化设计，以及设计，制造和分析的多视图表示和建模等功能。为了实现这一目标，我们进行了以下研究。我们开发了考虑由数值计算引起的模糊几何元素是简并的拓扑约束推导算法，根据简并状态之间的转换规律得到一致性约束，并从约束中得到输出的拓扑实体。我们介绍了一种方法，该方法描述了特征模型中的拓扑约束，这种约束来自于一种类型的特征和附加特征的产品的面，并表示了来自设计者关于特征的分配和大小的指示的几何约束。当一个参数改变时，我们修改产品形状检测拓扑变化。在这里，我们获得了特征模型和几何模型之间的一致性，修改了特征类型和超过或在维度约束下。我们使用与产品模型中的基本特性类似的结构来表示复合特性，并使用户能够通过在XML文件中表示复合特性来访问网络上的复合特性库。我们还研究了检索相似特征和保护库不注册相同特征类型的算法。提出了一种根据制造要求（制造约束）自动选择设计参数并确定其值以改变产品形状的方法。利用几何约束中的依赖图提取影响制造约束的尺寸参数，根据属性信息选择对设计者意图影响最小的参数。然后，我们根据参数的变量，对人脸数据表生成的一个或多个方程求解得到值。少

Nowadays, CAD systems with parametric modeling functions are realized. However, efficient product development is not performed because designer's intent which was expressed as constraints and manufacturing information in the engineering drawings is not represented directly in a product model but as a history of commands and dimension values of shapes. Hence our object of this research is to develop functions such as symbolical representation of designer's intent using topological and geometrical constraints along with attribute information, efficient parametric design according to designer's direct indication, and representation and modeling of multiple views for design, manufacture and analysis. To achieve this objective, we have carried out the following research.1. We have developed algorithms which deduce topological constraints considering that geometrical elements with ambiguities caused by numerical calculation are degenerate, obtain consistent constraints according to transitio … More n rules among degenerate states, and make topology of the output solid from the constraints.2. We have introduced a method which describes topological constraints in a feature model from a type of feature and faces of a product where the feature is attached, and which represents geometrical constraints from designer's indication concerning allocation and sizes of the feature. When a parameter is changed, we modify the product shape detecting topological changes. Here, we obtain consistency between a feature model and a geometric model, modifying a feature type and over or under constraints of dimensions.3. We have represented a compound feature using a similar structure as a basic feature in a product model, and enabled users to access a library of compound features on the network by representing them in a XML file. We have also studied algorithms for retrieving resemblant features and protecting the library from registering the same feature type.4. We have developed a method which selects a design parameter and determines its value automatically to change of a product shape according to manufacturing requests (manufacturing constraint). We pick up dimensional parameters which affect the manufacturing constraint using the dependency graph in the geometrical constraint, and select the parameter which has the least influence on the designer's intent according to the attribute information. Then, we obtain the value solving an equation or equations generated from the face data table against the variable of the parameter. Less