A Family Of Surface Geometric Deformation Methods And Its Application In The Product Design

The geometric deformation design of product surfaces is one of the key technologies for the product design, such as automobiles, airplanes and ships. The deeply study for geometric deformation design of product surfaces technologies and methods provides theories, methods and tools to support development of the product surface shape which well satisfies the customers’aesthetic needs, and it has important theoretical value and practical meaning. Concerning the geometric deformation design for product surfaces, the research focus is put on the algorithms which enhance development ability for the product shape, including the reuse of surface shape, the blend of surface geometric details, the transformation of shape deformation constraints manipulated by semantics and the generation of key geometric shape. The prototype system for product surface deformation design are developed and then used to research the surface shape design of automobiles.The dissertation is organized as follows:In chapter1, the development history of geometric deformation technologies of surfaces for product shape design and the research status are reviewed. To solve geometric deformation design problems of complex product shape, the research significances of geometric deformation technologies of surfaces are analyzed, the key technologies impacting the modeling shape for the product shape design are discussed, and then the whole research contents and structure of the dissertation are introduced in this chapter.In chapter2, the surfaces merging and blending methods based on multi-resolution analysis are proposed. The measure concept for weighting the surface fairness is defined to be the specific standard for judgment of surface fairness. The merging and blending methods for NURBS surfaces based on properties that the wavelet base can be multi-scale decomposed are presented. In the wavelet decomposition framework, the surface geometric information can be decomposed gradually, then the noise part can be filtered by proper threshold value, finally the fairly merging surface can be reconstructed.In chapter3, the transplantation methods of geometric features based on surface feature membrane are proposed. The normal feature membrane is defined to describe surface geometric features, and the goal to obtain interesting surface features can be complemented by extracting the normal feature membrane. Therefore, the copy and paste operation of geometric features of complex product shape surfaces can be achieved by adjusting the normal feature membrane of source surfaces and transplanting the feature membrane to the target deformation surface.In chapter4, the transformation of surface deformation constraints manipulated by the abstracted semantics are proposed. According to the different geometric shape feature described by the semantic features, the semantic features are associated with the related geometric constraint condition. The generation of geometric feature parameters are controlled by numeric constrain conditions from semantics, therefore, the surface with geometric features from abstract semantics are obtained.In chapter5, the surface shape deformation methods based on skeleton curves are proposed. The skeleton curve is defined to describe the key geometric features of surfaces. The skeleton curves (e.g. ridge and valley lines) reflecting the geometric features of product shape surfaces are extracted, and then are deformed under the given constrain conditions to manipulate variation trend of the target surface shape, therefore, the enhancement of the given key geometric shape features of the surface can be completed.In chapter6, the geometric deformation design for surfaces system is designed and developed. The software architecture, the implementation technology of each function and the design idea are discussed. The applications demonstrate that efficiency of the geometric deformation design for product surfaces is improved efficiently by this software system.In chapter7, the conclusion of the main study results and important innovations are given along with prospects of the related research in this dissertation.