Patterns for Collaborative Virtual Reality

The paper considers two design patterns enabling to extend automatically a virtual prototyping application into a collaborative application. The proposed patterns deal with distributed designation and automatic aggregation. They provide adequate properties in term of cooperation and mobility while guarantying good usability over the standard Internet. Thus, distant participants can share and cooperate to define common agreed design of a virtual prototype while alternating between disconnected and meeting works. These two patterns take part of a more complete framework including several other patterns that address distributed protection, meeting schedule, real time membership, real time awareness, progression, parallel work, refreshment, security, address allocation and multicast connectivity. First pattern provides a distributed designation of a virtual scene tree that supports mobility. Unique names are maintained in a fully distributed way among disconnected workspaces and meeting replicas. Second pattern addresses the aggregation of different disconnected workspaces into a global scene tree. That aggregation mechanism relies on a peer-to-peer communication model. It enables to aggregate the scene while working on it. Different patterns of our framework rely on existing patterns that we compound. They capture an efficient style of distribution through reuse of existing architectural patterns. The whole framework runs on Unix and Windows, can be deployed easily on the standard Internet, is fully distributed and supports efficiently mobility and conciliation meetings. It is used in a virtual prototyping application at EADS