A Multiuser 3D Web Browsing System

T he Virtual Reality Modeling Language sets an open-standard file format for designing 3D multimedia and shared virtual worlds on the Internet. VRML was originally designed to support the interaction of multiple participants in the World Wide Web environment—that is, to network virtual worlds via hyperlinks. However, even version 2.0 of the standard, published in August 1998, did not fulfill this design goal. The development of VRML has nevertheless spurred broad research on distributed multiuser VR systems. Such systems generally provide mechanisms for the multiuser server to “remember” the information of registered participants and to process the messages communicated among them (see the sidebar, “Related Work,” on pp. 72-73). To take advantage of the Web environment, however, a distributed multiuser VR system must be seamlessly integrated with the Web architecture so that users can download virtual scene files from any supporting Web server and navigate transparently to other virtual worlds through other Web servers. Such integration would include full access to the services provided by the Web environment. In this article, we describe SharedWeb, a 3D Web browsing system that was designed and implemented to support interaction among clients in the existing Web environment.1 We begin by describing the methodologies and mechanisms used to achieve seamless integration with the Web environment, then we summarize the SharedWeb system implementation. We present some experimental results that show the effects of different frame rates and threshold values on system performance, and conclude with discussions of two virtual worlds currently supported by the system.