Intelligent Systems Report € September € 1996 € Volume 13 € No. 9

SIGGRAPH '96:
VR expands the field of possibilities

By David Blanchard
Editor

The virtual reality (VR) field suffered a potentially crippling blow earlier this year when its largest conference and exhibition - the VRWorld show - was abruptly canceled. Fortunately, the VR industry had an even bigger venue at which to showcase its latest technological marvels - the huge SIGGRAPH '96 Conference on Computer Graphics and Interactive Techniques, held last month in New Orleans, La.

Certainly not all of the 28,500 SIGGRAPH attendees ventured to the Mississippi Delta solely to see the state of the art in VR developments, but thanks particularly to the emergence of the Virtual Reality Markup Language (VRML) 2.0 standard, VR's influence was ever-present and profound.

All of the energy and enthusiasm that used to characterize the AI field in the 1980s seems to have shifted over to such pursuits as 3-D interactive design, visual simulation and virtual prototyping. Conference chair John Fujii of Hewlett-Packard opened the technical program by observing, "By taking a chance here, by seizing an opportunity there, [we] expand the field of possibilities. It is not merely the power of the processor, but it is the power of the ideas springing from our connected pursuits that guarantees an exciting future for us all." And indeed, with more than 320 exhibitor booths luring attendees away from the technical sessions, there was a plethora of ideas and pursuits, all charged by the opportunity to further the development of computer graphics.

In this special SIGGRAPH '96 show issue of ISR, we will look at some of the significant VR developments being undertaken by the R&D community, as well as profile the latest generation of hardware and software introduced at the exhibition.


HMDs vs. SIDs
SIGGRAPH '96 devoted a panel presentation to forecasting the future of virtual reality, centering on a debate of the merits of the traditional head-mounted displays (HMDs) versus the more recent spatially immersive displays (SIDs) such as the University of Illinois' CAVE, a theater-like domed video projection.

According to VIRTOOLS' Bertrand de La Chapelle, "HMDs are ill adapted for day-to-day professional applications," due to such problems as weight, eye and neck fatigue; the isolation factor that makes it difficult for collaboration; the need for better performance; and even the psychological stumbling block that HMDs are considered game gear and are not taken seriously in business environments. He believes that SIDs offer a better chance for collaborative applications, though they too face major drawbacks: underdeveloped, very expensive and requiring much more space and hardware.

"As VR applications evolve from simple walk-throughs to virtual working environments, SIDs might become the new paradigm for professional use," De La Chapelle predicted. "Key developments in graphics hardware and projection devices will create a range of standard systems, from individual large screen displays to full-fledged multi-participant domed environments."

Alternate Realities' David Bennett agreed that spatial immersion, particularly dome projection, "provides a better solution than other alternatives for groups of people." While HMDs remain a valid and important development environment for single users, Bennett observed that "acceptance of domes for VR is greater than for HMDs since it does not require wearing any restrictive devices and `feels' more like what is expected of VR."

Mark Bolas of Fakespace cautioned against abandoning the HMD simply because of its technological challenges. "Are we so lazy that we'll shy away from the hard problems of cutting-edge immersive displays to move toward the relative utility and security found in projection-based and other alternative displays?" According to Bolas, the R&D community needs to focus on making "both the display technology and the content work together to form a seamless immersive experience."


The emergence of VRML
VRML 2.0, also known as Moving Worlds, has emerged as the standard multimedia description language, enabling interactive 3-D animations for the World Wide Web. Thanks to VRML 2.0, "Networked, interoperable, interactive 3-D graphics are now feasible for everyone's computer," remarked Don Brutzman with the U.S. Naval Postgraduate School.

"Although networking has been considered `different' than computer graphics, network considerations are integral to large-scale interactive 3-D graphics," he observed. "Graphics and networks are now two interlocking halves of a greater whole: distributed virtual environments. Our ultimate goal is to use networked interactive 3-D graphics to take full advantage of all computation, content and people resources available on the Internet."

A lofty goal indeed, and as Silicon Graphics' Gavin Bell explained, VRML 2.0 has been viewed as successful because "it hasn't tried to solve all of the problems of computer graphics, simulation and networking all at once." As one of the architects of VRML 2.0, Gavin described what work remains to be done: "Tackling the multi-user problem will require agreement on exactly which problem should be solved - multi-user chat is a much easier problem than general multi-user collaboration in a shared virtual world. Solving the more general problem will require additions to both VRML and the infrastructure of the World Wide Web."
Will workstations become obsolete?

With the emergence of more powerful and affordable graphics accelerators for PCs, some pundits have begun to forecast the eventual demise of workstations. For instance, Michael Cox of S3 predicted, "PC graphics will drive workstations into Chapter 11. At the top of the market pyramid are the few users who need astronomical performance at astronomical prices. At the bottom are the PC masses. PCs will ultimately take the whole pyramid because of unyielding forces: business model, technical requirements, and volume."

Not surprisingly, Sun Microsystems' Michael Deering sees the future quite a bit differently. "Three-D graphics hardware for PCs have finally found their killer apps: home games. The most successful PC vendors are busily dumping their half-hearted attempts to achieve workstation quality in an effort to shave a little cost off to be more price competitive in the cutthroat 3-D home game market."

While vendors will continue to expound on the state of the industry as it reflects most favorably on their own niche, the undeniable truth that emerged from SIGGRAPH '96 is that whether it's on a PC or on a workstation, whether it's delivered via an HMD or within an SID, whether it conforms to the VRML 2.0 standard or not, virtual reality has become a mature technology for developing and enhancing intelligent applications.