Research On Some Key Technologies Of Multi-platform Drawing System

The intact drawing not only includes the two-dimensional projection of the entity, but also includes many kinds of national standard objects such as Frame, Title Table, etc. Most CAD systems at present with power three-dimensional modeling function, but unable to finish above-mentioned national standard objects conveniently. With the development of network technology and concurrent engineering, individual design is gradually replaced by collaborative design; The changing of design method has put forward the new request to CAD, for example, it is a problem needs to be solved that how to overcome the loose integrated disadvantage which only through client, can CAD exchange data with collaborative platform in traditional mode.This paper promotes the function of CAD system in two aspects which include the operations of national standard objects and the cooperative design mode, some key technologies in implementation of multi-platform object as follows is studied:Firstly, on the basis of the hierarchical structure of system objects which is based on group's technical, four layers structure of system is set up. To avoid changing the realizing of objects layer and function layer so as to provide convenience for the transplantation of system, basic classes & API layer is designed to encapsulate the API of different CAD platforms.Secondly, based on the feature of drawing, the model of drawing information is set up. By the analysis of the relation between the features, the technology of management of multi-layer nested groups is presented. Then, the management of feature expression of drawing based on extend-attribute is studied.Thirdly, the cooperative design mode based on Local Work Space (LWS) is put forward. LWS is a working module which acts as client and can promote the cooperative design function of CAD. By embedded in CAD system, LWS could realize the management of local data and seamless integration between CAD and collaborative platform.System which is implemented on Unigraphics and Pro/Engineer based on the technologies above is applied in the third academe of CSMES and Liuzhou Moters Co, LTD successfully.