A distributed collaborative design environment is presented to improve the efficiency of gear trains design.An objected oriented model for gear trains is built to support the expression of design information both in conceptual design and detailed design and the exchange of design information between the two stages.To satisfy the security requirements of collaborative design environment

the role-based access control model is extended with attribute.The designers could concurrently modify different components of a gear train relevant to his or her role.The development of the design environment is based on the object oriented model and extended role based access model

of which the engineering application approves its applicability.