The CAVE is a multi-person, room-sized, high-resolution, 3D video and audio environment. It was developed at EVL and is available commercially through Pyramid Systems Inc. The CAVE library is available through VRCO. EVL continues to research and develop the CAVE.
Virtual reality may best be defined as the wide-field presentation of computer-generated, multi-sensory information which tracks a user in real time. In addition to the more well-known modes of virtual reality - head-mounted displays and binocular omni-oriented monitor (BOOM) displays - the Electronic Visualization Laboratory at the University of Illinois at Chicago introduced a third mode in 1992: a room constructed of large screens on which the graphics are projected onto the three walls and the floor.
Specifically, the CAVE as installed at EVL, is a theater 10x10x9 feet, made up of three rear-projected screens for walls and a reflective projection for the floor. High resolution, high bandwidth, short persistance CRT based Electrohome Marquis 8000 or 8500 projectors throw full-color workstation fields (1024x768 stereo) onto the screens, giving approximately 3,000 linear pixel resolution to the surrounding composite image. Computer-controlled audio provides a sonification capability to multiple speakers. A user's head and hand orientation and position are aquired using an Ascension tracking system with tethered electromagnetic sensors. Stereographics' LCD stereo shutter glasses are used to separate the alternate fields going to the eyes. Currently an InfiniteReality Engine is used to create the imagery that is projected onto the walls and floor. The CAVE's theater area sits in a 30x20x13-foot light-tight room, provided that the projectors' optics are folded by mirrors.
Goals that have inspired the CAVE engineering effort include:
- Presenting higher-resolution color images and improved surround vision.
- Reducing the amount of encumbering hardware the user has to carry.
- Reducing geometric distortion.
- Eliminating errors induced by head rotation.
- Developing a display devise that permits the simultaneous viewing of reality and virtual reality (i.e., one's own hand, an input device, or a collaborator's gesture).
- Developing a visualization tool which can be coupled to networked supercomputers and data sources.
"CAVE", the name selected for the virtual reality theater, is both a recursive acronym (CAVE Automatic Virtual Environment) and a reference to "The Simile of the Cave" found in Plato's Republic, in which the philosopher explores the ideas of perception, reality, and illusion. Plato used the analogy of a person facing the back of a cave alive with shadows that are his/her only basis for ideas of what real objects are.
Since it's premier at the ACM SIGGRAPH '92 conference, the CAVE has achieved international recognition as an excellent virtual reality system and a compelling display environment for computational science, engineering, and art. It has been put to use in industry, and has proved its worth as a rapid prototyping device. Research has been undertaken at EVL into using the CAVE as a collaborative environment for design and education. CAVES have been installed at research, business and art institutions.