Shaking Hands in Cyberspace

Multiuser VR lets users collaborate in cyberspace on everything from the latest surgical application to car design or just playing games

Rainer Mauth

Virtual reality (VR) has made considerable inroads into the realm of industrial and commercial applications. The automotive industry, for example, uses VR applications to verify instrument accessibility and visibility. Surgeons use the technology to plan and practice complex medical operations. And interactive VR adventure games are becoming more common on home PCs.

The most impressive VR achievement to date, however, involves multiuser VR over dedicated lines or the Internet. In such a distributed virtual world, users can even exchange objects or shake hands. The se applications aim mainly at collaborative design environments, virtual shopping, and entertainment.

In February, at this year's Virtual Reality World show in Stuttgart, Germany, the VR developer Division (Bristol, U.K.) demonstrated a global, real-time collaboration in an interactive, VR environment with three concurrent users. Each of the three cybernauts in Stuttgart, Paris, and Redwood City, California, was equipped with a head-mounted display and a 3-D "flying mouse" as an input device. The demonstration operated on three standard Unix workstations at the three locations, interconnected over ISDN, and with Division's VR software, known as dVS.

"It might as well run over the Internet," says Pierre DuPont of Division, "but the transport latency of today's Internet is still a problem." The company's dVS product uses standard TCP/IP protocols for communication between remote computers.

However, the system handles geometry, graphics, rendering, and the behavior of a ll objects locally. A distributed DBMS replicates and controls system updates in the local databases. Therefore, the network is used only to transfer changes in the environment and user orientation.

Division's VR authoring software, known as dVise, imports and exports Virtual Reality Markup Language (VRML), the Internet's 3-D format. However, much of dVise's information is lost during the conversion to VRML because VRML does not support such features as modifying objects. DuPont says that VRML is not sufficient for multiuser VR because it doesn't provide enough interactivity and object behavior.

Other companies, such as Superscape (Hook, U.K.), echo the need for an enhanced version of VRML. Superscape's latest 3-D viewer, VisNet, supports VRML and SuperVRML, the company's extension of VRML. SuperVRML includes features such as collision detection, object behavior, and a fast rendering algorithm called x-buffering.

Superscape's VisNet interactive viewer runs on all Windows platforms and on SGI Irix. It operates either as a stand-alone helper application or as an in-line plug-in for Netscape's and Microsoft's Web browsers.

Web-site information: http://www.division.co.uk and http://www.superscape.com .

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Virtual Automobile Reality

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An example of multiuser car maintenance in virtual reality across the Internet.