Virtual Reality and the CAVE
Students and researchers at the University of Illinois - Chicago developed what many VR specialists feel is the most immersive display system for VR environments. It's called the CAVE system, which stands for Cave Automatic Virtual Environment.
 Courtesy of Dave Pape A CAVE VR system allows the user to move through |
A CAVE is a small room or cubicle where at least three walls (and sometimes the floor and ceiling) act as giant monitors. The display gives the user a very wide field of view -- something that most head-mounted displays can't do. Users can also move around in a CAVE system without being tethered to a computer, though they still must wear a pair of funky goggles that are similar to 3-D glasses.
Walk on the Virtual Side While the CAVE gives
the user more freedom of movement than other VR setups, it’s still
pretty limited -- most CAVE systems are 10 feet square or smaller.
Several researchers with the University of North Carolina - Chapel Hill
developed a technique to expand the size of a CAVE artificially. The
technique is called redirected walking -- the system tricks the
user into walking in a curved path, but the user believes he is
following a straight line. To accomplish this, the VR system slowly and
imperceptibly rotates the virtual environment around the user. This
causes the user to feel as if he is off balance, and so he adjusts to
get back on track. The end result is that the system can influence the
user to walk in circles while the user believes he is following an
uninterrupted straight path [Source: University of North Carolina - Chapel Hill]. |
The active walls are actually rear-projection screens. A computer provides the images projected on each screen, creating a cohesive virtual environment. The projected images are in a stereoscopic format and are projected in a fast alternating pattern. The lenses in the user's goggles have shutters that open and shut in synchronization with the alternating images, providing the user with the illusion of depth.
Tracking devices attached to the glasses tell the computer how to adjust the projected images as you walk around the environment. Users normally carry a controller wand in order to interact with virtual objects or navigate through parts of the environment. More than one user can be in a CAVE at the same time, though only the user wearing the tracking device will be able to adjust the point of view -- all other users will be passive observers.
In the next section, we'll look at another kind of virtual reality display called the workbench.
