Abstract: Most of collaborative designs today are based on the asynchronous mode. A methodology and its implementation of the web-based synchronously collaborative product design is described from three aspects, which mainly deal with infrastructure, enabling technologies, and software prototype. Here, the enabling technologies include the privilege control, the autonomous appointment mechanism, sharable synchronous feature modeler guided with a dynamic generating principle of activity chain, etc. Furthermore, a novel CAD mode is put forward. It depends on browser/server/database 3-tired grouping architecture and can be evolved to the application service provision (ASP) mode easily. It may be said that this research will be useful for e-commerce-driven CAD innovation.

Key words: Collaboration, Synchronous mode, Tele-design, Web