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A non-profit publication of the Office of the University Relations of Virginia Tech,
including The Conductor, a special section of the Spectrum printed 4 times a year

Computer-created images make CAVE unique

By Liz Crumbley

Spectrum Volume 19 Issue 01 - August 29, 1996

Engineers at Caterpillar Inc. enter the CAVE to design and test new construction equipment. Meteorologists use the CAVE to simulate tornadoes and other severe weather events. Medical researchers with access to the CAVE can step inside the AIDS virus and see in detail its deadly structure.

In 1997, Virginia Tech researchers, students and industrial affiliates will be able to design, explore and study a limitless range of subjects, when the CAVE comes to campus as part of the university's development of an Advanced Communications and Information Technology Center (ACITC).

The CAVE (Cave Automatic Virtual Environment) was created by the Electronic Visualization Laboratory at the University of Illinois. The National Science Foundation (NSF) has awarded a grant of $850,000 to Virginia Tech for the acquisition of a CAVE as an interdisciplinary research and educational tool. Several Tech colleges and the university's Research Division also are contributing funds for the $1.6-million project.

But what is the CAVE?

It has three walls, a floor, and a 15-foot-high ceiling. The walls and floor are screens that receive three-dimensional images from four video projectors. The images, produced by high-powered computers, are projected in stereo so users wearing stereo glasses find themselves immersed in 3-D space. The CAVE also has a synchronized sound system.

Images are created on SGI workstations or personal computers with software such as Electronic Visualization Libraries or SENSE8 and then relayed to a master computer that operates the video projection system.

The CAVE user can manipulate projected images with a wand, which is similar in function to a PC's mouse. The wand enables the user to put images in motion and to isolate segments of images for analysis or repositioning.

The CAVE can hold up to 10 viewers, each of whom will experience all of the visual and auditory sensations that simulate "being there."

A test pilot, for example, can sit in a folding chair inside the CAVE while projected images offer him the sensory experience of being at the controls of a fighter jet. "He can test-fly and crash the jet a hundred times and never be hurt or lose an airplane," said Ron Kriz, associate professor of engineering science and mechanics at Virginia Tech.

Kriz, director of Tech's Visualization Laboratory, helped spearhead the effort to bring the CAVE to the university. The NSF selected Tech as a grant recipient because the CAVE project has broad-based support throughout the university and because the Human/Computer Interaction (HCI) Group can evaluate CAVE technology and functions.

At Virginia Tech, the CAVE can be used by faculty members and students from all university disciplines. Mathematics professors can bring their students inside geometric shapes. Engineering classes can put together and take apart complex structures. Veterinary surgeons can prepare for operations by viewing large-scale simulations of animal organs. Architect students can design 3-D structures and rearrange them with the wave of a wand.

Three research areas are targeted for CAVE applications during the first year of use: molecular modeling in biochemistry, failure and reliability in fiber-reinforced composites, and molecular modeling in material science.

Tech students and faculty members already have access to computer graphics and modeling programs, but the CAVE offers visual information that cannot be delivered by flat computer screens or virtual-reality helmets, Kriz says. "With sight comes insight. In the CAVE, I can control a complete scene or structure. If I can control a structure, I can design a new property for it."

Kriz says Tech CAVE users also will include industrial affiliates. Five companies already have expressed an interest in using the CAVE, where they will be able to design and test products without incurring many of the traditional research-and-development costs.

The University of Illinois has garnered $12 million worth of industry contracts for use of its CAVE, Kriz said.

The Tech visualization lab will provide university-wide technical support for the CAVE and its users. Kriz and his NCSA CAVE colleagues can help university and industrial users create their own programs.

The Tech HCI Group, led by Computer Science Department Head John M. Carroll and research scientist Deborah Hix, will provide training in CAVE use and will develop 3-D interfaces between users' computers and the CAVE system.

The NSF grant also enables Tech to form a partnership with the University of Illinois National Center for Supercomputing Applications (NCSA). NCSA is providing the developmental hardware for the CAVE free of charge in exchange for evaluations by the Tech HCI Group, which will test CAVE users, collect usability data, and perform cost/benefit analyses to find and resolve CAVE performance problems.

The partnership with NCSA also enables Tech to become a super-computing center, which will provide Tech CAVE users with access to a powerful nation-wide computer graphics network. "A user at Tech could receive graphics from an electron scanning microscope in a lab across the country," explains Kriz.

"There are only four CAVE infrastructures in the world," Carroll said. "Virginia Tech's project represents a major acquisition of research equipment that can be used by people in a wide variety of fields."

To make the CAVE an interdisciplinary tool, to put it in use university-wide and make it available for industrial affiliates as well, and to ensure that it is accessible to faculty members and students will be a complex undertaking, Kriz acknowledged. However, he believes, that is what makes the Virginia Tech CAVE proposal exciting. "You can't differentiate research from education in this project," he said.