Validity Maintenance In Semantic Feature Modeling

Feature modeling is product-oriented and it is an important milestone of CAD development,which really makes integrated CAD/CAPP/CAM possible.It is also the theory and technological foundation of solving products problems.The integral model of product information based on feature should be built,which can solve data exchanging and data sharing in the process of designing,producting,quality controlling,and organization management.At the same time,the parametric design technique is applied to feature-based design system,where the feature can be adjusted ,which improves the efficiency of designing process.There are many drawbacks in some aspects such as product model editing in the current systems based on process.People study the feature model from managing geometry model elements and put forward the feature model based on cell.In order to overcome those shortcomings and improve modeling ability and efficiency,they apply the feature dependency graph which makes feature modification independent on process tree.This paper has a further study on the key technology called validity maintenance mechanism in semantic feature modeling In order to maintain the intent of designers and satisfy them.The method combines geometry model and semantic feature modeling,setting up new feature representation,cell element naming and identification method.In the meantime,a history-independence interactive feature boundary re-evaluation algorithm is presented based on feature editing.Moreover,the validity recovery mechanism after invalid feature operation can maintain the original feature model.The above ideas have been realized on HUST-CAID(Computer Aided Industry Design System developed by Harbin University of Science and Technology) preliminarily.