Networked VR From A Cave

John Vacca and Dave Andrews

Most Internet VR (virtual reality) projects don't support immersion, where you wear a helmet and gloves and are immersed in a simulated environment. But researchers at the Electronic Visualization Laboratory at the University of Illinois at Chicago ((312) 996-3002) have developed a new model for networked VR, called a Cave.

A Cave is a 3-D environment that consists of a 10- by 10- by 9-foot room with three rear-projection screens for the walls and a down-projection screen for the floor. Instead of wearing a helmet, viewers wear LCD stereo shutter glasses that separate the alternate fields going to the eyes. Images on the screen "move" with the viewers and surround them. An image's direction and positioning are determined by a person wearing a magnetic tracking device from Polhemus (C olchester, VT). The computers supplying the power behind a Cave are from the Silicon Graphics Supercomputing Systems Division. They can handle the billions of FLOPS required when interacting with complex representations of weather patterns, seismic activity, or industrial CAD/CAM designs.

Tom DeFanti (Tom@uic.edu), the director of EVL, says that so far, researchers exploring networked Cave-to-Cave simulations have proven the concept of remote person-to-person immersive reality by performing basic actions (e.g., one person "touches" another person's head) over the Internet using a T1 line. For more complex applications, DeFanti is waiting for the activation later this spring of a VBNS (Very high Bandwidth Network Service) line that will dedicate a 155-Mbps ATM (asynchronous transfer mode) line between two supercomputer centers.

A Cave represents the high end in networked VR. DeFanti notes that solutions like VRML can't address the needs of these high-end VR applications. "If you need to sit in a simulation of a car, you want to reach out and see that everything is in the right place," he says. "You can't do that in a workstation." As you might expect, the price of a Cave is high. But DeFanti says that for some companies, the price is worth it. "It's beneficial enough that several of our clients are building Caves," he says. "Considering that the price is about $1 million per Cave, there's obviously some real communication going on."