Research On Feature-based Technology Of CAD Data Exchange

This thesis looks back on the phylogeny of geometric modeling technology and indicates that the feature and history-based modeling technology, which has been extensively applied in industrial community, is a fruit of research on CAD technology. And then points out that, the low hierarchy where data exchange occurs and the missing of high-level design intent of design is the main shortages of the current product exchange data technologies, based on the investment of the phylogeny of product exchange technology and analysis of the basic characteristics of current product exchange data technologies. This thesis puts forward a new approach, called feature-based CAD data exchange, to solve these problems. In this new approach, product exchange is realized by the feature level, and the exchanged data is not the low-level semantic data, such as boundary or mesh, but the compacted high-level semantic data, such as the feature or history information. By this new approach, CAD system can easily reconstruct the model by evaluation with the exchanged data, and the high-level design intent of design will be maintained efficiently.In order to implement such a feature-based CAD data exchange approach, the implement differences of different CAD system should be resolved at first. Based on mapping of modeling function set and data exchange Add-in of each CAD system that can easily call modeling API, this new approach resolve the implement differences. The mapping of modeling function set is the union of function sets of current CAD systems. In the mapping of modeling function set, the function and the approach of feature-based modeling is independent, with a mapping of one to many. Meanwhile, other key technologies are also discussed thoroughly in this thesis, such as coordination transformation, intermediate data saving and features location.To validating the feasibility of this new approach, Add-ins are developed by COM-based API of SolidWorks 2005 and Inventor v8.0. Data exchange of some features, such as extrude, revolve, sweep, fillet, chamfer, mirror, and are implemented on Add-in. By using this new approach, the exchanged CAD model of Inventor can be edit in SolidWorks, so high-level design intent of design is reserved. Meanwhile other advantages can be concluded, it is more efficient and produces smaller size intermediate data files.