Jumping down the virtual rabbit hole

Samuel Fulcomer confidently jumps off a ledge on the second floor of a library. His stomach may drop, but when he lands, he emerges uninjured and moves on to his next destination.

Mr. Fulcomer is not the Bionic Man. He performs his superhuman acrobatics while standing in a "virtual environment," a computer-generated setting that surrounds the senses.

The 8-foot cube, affectionately called "the cave," is part of the recently inaugurated Technology Center for Advanced Scientific Computing and Visualization at Brown University in Providence, R.I.

Fulcomer, director of the center, finishes his tour of the virtual library and runs another simulation in the cave. This time, he finds himself in a cartoon-like room with a virtual bookshelf, table, chairs, and a rug.

Wearing special gloves, he pulls a virtual book off the shelf, holds it momentarily and then puts it back.

When he brings his hands close together, a blue sphere appears out of nowhere, floating between them. "Green," he says into a microphone clipped to his shirt, and the sphere turns green. "Cone," and the sphere morphs into a cone.

The demonstration over, Fulcomer picks up the cone and throws it over his shoulder.

He then proceeds to change the scale of the entire room and make it look like Lilliput or a distorted room from Wonderland, by pointing at a wall and firmly pushing down or pulling up.

But the cave is not merely a playpen for adults. Brown plans to use it for scientific studies that range from learning more about the physical properties of the universe to understanding how humans visually process information.

"One of the ideas is to establish common ground between different scientific fields," says Fulcomer.

The projection-based system creates an immersive type of virtual reality that will allow researchers to manipulate and experience their data viscerally.

By comparison, when researchers work with data on desktop computers, the screens only have two-dimensional images. Researchers can't step back and look at graphs of data from the side or from behind.

Virtual reality will enable researchers to stand in the middle of a three-dimensional environment that responds to their movements. In this way, they can interact with data in three dimensions rather than just view it on a flat surface.

Gerald Guralnik, professor of physics at Brown, hopes to be able to stand in the cave and look at three-dimensional representations of mathematical calculations of elementary particles, such as atoms, and their quark content.

Dr. Guralnik says the new technology could help physicists use what they see in the cave to guide their calculations - what computer scientists call "interactive steering."

"It's like walking into Wal-Mart wanting to buy a book and looking around to discover that you're in the pharmacy aisle," he explains. If researchers just have a pile of numbers and no visualiza-tion techniques to guide them as to which numbers are important, it can take an extremely long time to get results, he says. "It is not unusual for us to run a supercomputer for a year or more and get a single result."

Researchers in the geological sciences expect to use the cave for a variety of studies, ranging from virtually exploring the surface of Mars and looking at visual representations of earthquake waves, for example.

Geology professor Marc Parmentier anticipates using the cave to understand how fluid material within planets, such as volcanic centers, moves and evolves over time.

To Michael Tarr, professor of cognitive and linguistic sciences, the cave is a controlled environment where researchers can study movement of another kind. By studying human visual perception, Professor Tarr and his colleagues hope to investigate the type of information people use to move.

The $8-million center, which is funded in part by a National Science Foundation grant, is the outcome of a collaborative

effort between the university and IBM and is the newest addition to a number of virtual environments at universities across the country.

The technology, however, is still cumbersome. To experience virtual reality, users must wear 3-D glasses and magnetic head and hand gear that are hooked up to tracking devices. The head tracker provides information about the user's position while a computer calculates images for each eye.

The illusion of the cave depends on the computers' response time to head movements, how many times per second images update, and the resolution of the display device.

Four projectors throw computer-generated images onto the three walls and floor of the cave while two IBM supercomputers run the simulations.

The next step, Fulcomer says, is to add three-dimensional sound and physical feedback, such as pressure against the skin when touching a virtual molecule. But the center is still far from being able to do this, he adds.

These are early days, concurs computer science professor Andries van Dam. "The whole idea of virtual reality is still at the Kitty Hawk stage."

(c) Copyright 1999. The Christian Science Publishing Society

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