A new history-independent modeling approach for feature-based design

Abstract

The majority of current feature-based modeling systems employ model history to store feature creation operations and re-execute them sequentially after each modification, which is called history-based modeling. Due to the static feature creation order, history-based modeling causes some problems during the reevaluation of the model, such as the evaluated model does not correspond to its specification, the operation can only refer to the boundary entities created by the previous operations, high computation cost, etc. In this research work, a new history-independent modeling approach is proposed. For the "remove feature" operation, only boundary faces originating from the feature being removed, and the intersecting features are modified for updating the resulting BRep model. For the "modify feature" operation, the feature being modified is first removed from the product model and then re-added with the new specifications, thus its creation step in the model history is changed. As a result, some of the problems caused by the static feature creation order are solved. During the reevaluation, the computation time is dependent solely on the execution of the feature and its intersecting features being edited. The computational complexity of the boundary evaluation using the proposed method for three representative models has been analyzed based on Open CASCADE. A case model was studied in a proof-of-concept prototype system to demonstrate the proposed modeling approach.