基于增量模型的协同CAD建模关键技术研究

ON KEY TECHNOLOGY OF COLLABORATIVE CAD MODELLING BASED ON INCREMENTAL MODEL

为了解决产品同步协同造型过程中由于模型信息庞大而造成设计修改无法及时反馈到客户端的问题,提出传输造型变化增量的方法。该方法避免修改后传输所有的模型信息,只需传输被设计修改影响部分的模型信息。提出了几何模型增量搜索算法,利用该算法搜索出协同CAD模型在修改前后发生变化的特征、拓扑关系和几何元素。将搜索结果封装成增量模型传输到客户端。设计出增量模型聚合算法,利用该算法将增量模型聚合到客户端原有几何模型上形成修改后的协同CAD模型。最后利用渐进式显示技术使协同造型设计者能更快地看到修改结果。

To solve the problem that the design modification can＇t be fed back to client due to too huge the model information is during the process of synchronised products collaborative modelling, this paper proposed a method to just transmit the varied modelling increments. By this way, the model informations to be transmitted to the client are those that which have been affected by the design modification so that the transmission of the whole model information after modification is avoided. The geometric model increment search algorithm was proposed to find out the changed features,topology relationship and geometric elementg after the CAD model was modified. The search results were encapsulated as the incremental model and were transmitted to the client. The model increment annexation algorithm was devised to annex the incremental model onto primary geometric model at the client to form the modified collaborative CAD model. At last, the collaborative designer can view the modified result of modelling quicker by the progressive viewing technology.