The paper presents the implementation of a system of Shared Virtual Reality (SVR) in Internet applied to a large- scale project. The applications of SVR to architectural and urban design are presented in the context of a real project, the new railway junction of Porta Susa and the surrounding urban area in the city centre of Turin, Italy. SVR differs from Virtual Reality in that the experience of virtual spaces is no longer individual, but rather shared across the net with other users simultaneously connected. SVR offers an effective approach to Computer Supported Collaborative Work, because it integrates both the communicative tools to improve collaboration and the distributed environment to elaborate information across the networks.