Ciao: A Collaborative, Immersive Architectural Layout System

This paper presents the design of a multiuser, large-scale -D layout system3 : Collaborative Immersive Architectural layout (CIAO). In contrast to many existing systems that sacrifice responsiveness to maintain consistency, CIAO achieves optimal response and notification time without compromising awareness or consistency. The optimal responsiveness is achieved by a new multicast-based, optimized concurrency control mechanism. Even operations on a group of related objects do not entail any latency for concurrent control. We also present the multiuser interfaces of CIAO that provide some sense of isolation as well as rich awareness. 1. Introduction Virtual environments can provide a user friendly interface to diverse applications such as battlefield simulation, virtual conferencing, and collaborative modeling[1][2][6][8][9][10][12]. Some of thes e applications, including battlefield simulation, require large scale virtual environments. City planning or the emerging electronic commerce can also benefit from the natural interfaces provided by large scale virtual environments. Tools for modeling individual object, laying out the modeled objects in the virtual environment, and walking through the environment are a must for building a large scale virtual environment. We present the design of a multiuser, large scale -D layout system CIAO (Collaborati3 ve Immersive Architectural layOut) in this paper. Because CIAO supports full functionality for layout and walk-through, one can construct virtual environments with CIAO in conjunction with a conventional modeler. Using CIAO, designers can try out what they think, and get realistic feedback instantly. In order to enable the synergy among a group of design participants, CIAO is designed to meet the following requirements: • Each participant must be aware of other members’ presence and their actions. (Awareness) • User actions should be responded to locally and be notified at remote sites as soon as possible. (Responsiveness) • Users perceive the shared virtual world in a consistent way, although they can manipulate the shared objects in the virtual environment. (Consistency)