Virtual environment for collaborative design occurs between people and often arounds 3D shared objects.Fruitful cooperation is helped by natural and intuitive ways of communication and interaction,for which responsiveness and consistency are leading factors.We examine an approach for providing efficient solution to virtual collaborative environment including 3D objects.In this approach,an improved client-server architecture is adopted to avoid the bottleneck of communication and performance,and role-based optimistic concurrency control is used to guarantee consistency and improve responsiveness.Moreover,a concurrency control scheme,in which the non-exclusive manipulations are merged,is used to undo a small quantity of manipulations rather than all the operations triggered by users who are not granted,therefore,a majority of concurrent operations are collision-free and executed immediately to maximize responsiveness.Finally,a collaborative virtual environment supporting3D product design is implemented for mechanical design,and experiment is conducted to evaluate the performance of 3D cooperative environment.Application and experiment show that the architecture and concurrency control strategies we proposed are effective and efficient.