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public demo time: Thursdays, 4pm
DAVE

Overview

The DAVE is an immersive projection environment, a four-sided CAVE.

A user in the DAVE.
A user in the DAVE, exploring the National Library in Vienna, Austria.
Wearing 3D glasses the user is immersed in the virtual world.

DAVE stands for Definitely Affordable Virtual Environment.
Affordable means that by mostly using standard hardware components we can greatly reduce costs compared to other commercial systems. Also, by exchanging just the graphics cards every couple of years and less frequently the PCs we can always use the latest graphics hardware for little money. Optimally using the available space we use a normal existing room without constructional changes.

In 2005 we built a new version of the DAVE here in Graz, Austria. This type of immersive display is the best way to explore virtual worlds. However it requires a large room and some effort. An alternative technology is the Head Mounted Display which is uncomfortable and typically has a much lower resolution.

DAVE 3D model.
Images are projected on the back projection side walls and on the
floor from above. We use mirrors to reduce the space needed.

Immersion

There are two main technologies why the DAVE is so convincingly immersive. One of them is stereoscopic vision. Each eye sees a slightly different image. This is done by using two projectors for each wall, showing images for the left and right eye alternatingly. The user wears lightweight LCD shutter glasses that are synchronized with the projectors. They are only transparent on one side at a time so the user can see the respective image.

Stereo Vision.
Stereoscopic vision: left and right eyes see slightly different images.
 
 
Shutter glasses.
Time interlaced projection with shutter glasses for stereoscopic vision.

The second important part is motion parallax with the help of head tracking. Depending on the user's eye positions, the image is rendered from the according view. As an example, the user can just move his head sideways to look around a corner of the virtual world. Our self developed optical tracking system uses infrared lights and cameras that can see little retroreflective marker balls. With triangulation their 3D positions can be measured. A fixed constellation of markers enables identification and measuring the orientation of an object.

motion parallax
Motion parallax: when moving the head, the scene content changes accordingly.

Technology

We use 8 render PCs and one controlling server, one file server and another PC for the optical tracking. Our projectors are the F35 AS3D from projection design with a 1920x1200 resolution. They include the XPort DCC120 module for time interlaced stereo. For interaction we mostly use a wireless joystick, equipped with markers.

DAVE applications.
A racing game, a glider simulation and an underwater world in the DAVE.

Applications

We mostly use viewers for interactive exploration of architectural models or user interface prototypes for demonstration purposes. We also developped a furniture placement tool for a virtual house. Mainly we use either our own davelib or the scene graph library OpenSG to facilitate software development or porting existing applications.

Video

Also have a look at our DAVE video from 2007:

Get the Flash Player to see this player.

Download the video above as flv file (7 MB).
The same DAVE video as DivX file (34 MB).

Public demos


click to enlarge
time: Thursdays, 4pm (except holidays).
location: Inffeldgasse 25E, first door on the left.
contact: davedemo@cgv.tugraz.at

 
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