Environmental Engineering Reference
In-Depth Information
The final category of interaction device is the wand or floating joystick. Basically, this device
works exactly the same as a conventional joystick, but it is not attached to a base that sits on
a tabletop. Instead, the joystick is equipped with an orientation tracker so the user simply
holds it in their hand and tilts it. Most flying joysticks also have some buttons on the stick
for “clicking” or selecting, similar to a mouse (Hsu, 1993).
4.6 Cave Automatic Virtual Environment
Cave Automatic Virtual Environment (CAVE) is an immersive virtual reality environment
where projectors are directed to three, four, five or six of the walls of a room-sized cube
(Fisher, 2003; http://en.wikipedia.org/wiki/Cave_Automatic_Virtual_Environment).
4.6.1 General characteristics of the cave
The CAVE is a large theatre that sits in a larger room measured of a varied size. The walls of
the CAVE are made up of rear-projection screens, and the floor is made of a down-
projection screen. High-resolution projectors display images on each of the screens by
projecting the images onto mirrors which reflect the images onto the projection screens. The
user will go inside of the CAVE wearing special glasses to allow for the 3D graphics that are
generated by the CAVE to be seen. With these glasses, people using the CAVE can actually
see objects floating in the air, and can walk around them, getting a proper view of what the
object would look like when they walk around it. This is made possible with
electromagnetic sensors. The frame of the CAVE is made out of non-magnetic stainless steel
in order to interfere as little as possible with the electromagnetic sensors. When a person
walks around in the CAVE, the person's movements are tracked with these sensors and the
video adjusts accordingly. Computers control this aspect of the CAVE as well as the audio
aspects. There are multiple speakers placed from multiple angles in the CAVE that give the
user 3D audio (http://en.wikipedia.org/wiki/Cave_Automatic_Virtual_Environment).
4.6.2 The first CAVE
The first CAVE was developed in the Electronic Visualization Laboratory at the University
of Illinois at Chicago. This was announced and demonstrated at the 1992 SIGGRAPH
(Fisher, 2003). The CAVE was developed in response to a challenge from the SIGGRAPH 92
Showcase effort for scientists to create and show off a one-to-many visualization tool that
utilized large projection screens. The CAVE answered that challenge, and became the third
major physical form of immersive VR (after goggles 'n' gloves and vehicle simulators).
Carolina Cruz-Neira, Thomas A. DeFanti and Daniel J. Sandin are credited with its
invention. It has been used and developed in cooperation with the National Centre for
Supercomputing Applications (NCSA), to conduct research in various virtual reality and
scientific visualization fields. CAVE is a registered trademark of the University of Illinois
Board of Regents (http://en.wikipedia.org/wiki/Cave_Automatic_Virtual_Environment).
4.6.3 How the CAVE works
A lifelike visual display is created by projectors positioned outside the CAVE and controlled
by physical movements from a user inside the CAVE. Stereoscopic LCD shutter glasses
convey a 3D image. The computers rapidly generate a pair of images, one for each of the
