DESPRAT

Web technologies evolutions during last decades fostered the development of collaborative vir- tual environments for 3D design at large scale. Despite the fact that collaborative environments gather in a same shared space geographically distant users in a common objective, the hardware ressources of their clients ( calcul, storage, graphics ...) are often underused because of the challenge it represents. It is indeed a matter of offering an easy-to-use, efficient and transparent collaborative system to the user supporting both computationnal and 3D design visualisation and business logic needs in heterogeneous web environments. To scale well, numerous systems use a network architec- ture called "hybrid", combining both client-server and peer-to-peer. Optimistic replication is well adapted to distributed application such as 3D collaborative envionments : the dynamicity of users and their numbers, the 3D data type used and the large amount and size of it... This document presents a..