Feature based technique has been widely used in object modeling as it provides a systematic representation reflecting the functionality of the object. By features, the generic shapes, characteristics, certain attributes and knowledge useful for reasoning can be associated to the object. However, traditional feature-based techniques are mostly limited to regular shape object and are not applied to free-form ones. For sculptured objects, different features are defined for particular application and each has its unique characteristic....[ Read more ]

Feature based technique has been widely used in object modeling as it provides a systematic representation reflecting the functionality of the object. By features, the generic shapes, characteristics, certain attributes and knowledge useful for reasoning can be associated to the object. However, traditional feature-based techniques are mostly limited to regular shape object and are not applied to free-form ones. For sculptured objects, different features are defined for particular application and each has its unique characteristic.

This thesis presents the application of feature-based technique in sculpture object modeling. We propose that in sculptured objects CAD/CAM, the best use of features can be derived only when we develop different feature sets for each particular domain. Mannequin models representing the shape of human being are constructed as an example domain. Feature decomposition based on natural anatomical partition of human body is applied. In this case, the features include neck, chest, waist, hip, legs, etc. Topological and geometrical information of each feature by a set of feature curves and feature points are defined. Parametric design basing on feature point adjustment is implemented to satisfy the metric constraint. Using the above technique, two series of mannequin models, male and female of different sizes have been generated. The procedures for data acquisition, feature, feature points and curves are presented. Parametric mannequin model construction and the issues involved are discussed.

Besides modeling, topological information carried by the CAD model is also useful in the manufacturing phase. Topological Projection Algorithm, which detects the similarity and changes between layers, is proposed for the "Layered Manufacturing Process" resulting in faster manufacturing planning. The algorithm is implemented and the benefits will be illustrated.