A virtual character serves as your guide in the experience that is the CAVE. Image courtesy of University of Illinois at Chicago's Electronic Visualization Laboratory.

"You walk into a ten by ten foot room, put on a special pair of glasses, and take hold of a 3-D mouse. As the program starts, the walls disappear. Now you are surrounded by the cobbles, stonework and red tiles of an Italian Renaissance city. Down the street you can see a cathedral. Pushing a button on the mouse moves you forward. Then you see an anomaly - a sleek, electric blue column. As you get closer, the column whirs and splits - a disjointed little figure unfolds. The figure gestures to you, then takes off. It looks back and beckons, `Come on!'

"You follow this strange guide to a dark stairway, winding up inside the cathedral. At the top, a low doorway takes you outside. The city stretches beneath you. Transparent pathways curl around the dome and lead back to the ground. You see the little guide far below. He is dancing wildly as a stream of flying letters and books sail past him and whip inside a building. What is in there .....?"

VR Without the Head Gear
This is a description of an experience in the CAVE virtual reality theatre. Virtual Reality is the art and science of using computers to create three dimensional worlds that users can be immersed in, explore as they please, and interact with in real time.

The CAVE, a recursive acronym for CAVE Automatic Virtual Environment, is a virtual reality display device, but not the kind of head-mounted display normally associated with VR. Instead, it's more like a prototype for Star Trek's HoloDeck; a room that people can enter, with stereoscopic computer images projected on the walls and floor. The computer continually updates and redraws the display as users move through the environment. One of the potentials of the CAVE is the creation of animated 3-D worlds and characters that a user can interact with, in effect making the user part of a story.

The CAVE's History
The CAVE was created at the University of Illinois at Chicago's Electronic Visualization Laboratory (UIC's EVL). EVL is a state of the art research lab for interactive computer graphics and brings together students from UIC's Schools of Engineering and Art and Design. It was founded in the early 1970s by Dan Sandin, art professor and creator of the Sandin Image Processor, a device well known in the video art community, and Tom DeFanti, engineering professor and author of GRASS, an early computer animation system. The Lab's work has always been a mixture of art, entertainment, engineering, and science. In the '70s, EVL staged public performances of interactive electronic art and provided the computer hardware and software used to create the original computer graphics in Star Wars. Later work included developing graphics hardware that formed one of the first home computer systems, investigating 3-D fractal imagery, and using visualization for scientific research with the National Center for Supercomputing Applications.

In 1991, DeFanti and Sandin decided to use their experience with video and interactive computer graphics to create a new approach to the growing field of virtual reality. Traditional VR systems were head-mounted and were usually a pair of small video displays attached to a helmet or mechanical boom. Most such displays were low-resolution, encumbering, and isolated the user. EVL's new device, the CAVE, used video projection screens to create a VR display that users entered, rather than wore. The CAVE display was high-resolution, only required the users to wear lightweight shutter glasses, and could be shared by whole groups of people at once. It was implemented by EVL students Carolina Cruz-Neira, Greg Dawe, Sumit Das, and others, and was first shown at the 1992 SIGGRAPH Conference in Chicago. The full system was completed barely in time for the conference and many of the demonstrated applications hadn't been seen in the CAVE itself before show time.