Game Development Reference
In-Depth Information
desks (or visiodesks) on the whole operate like the stereoscopic screens with separa-
tion done by eyeglasses, except that the image is projected on one (or two) screen(s)
by a video projector and if required, via one or two mirrors. The stereoscopic images
are separated using either active or passive eyeglasses. There are two possibilities of
three-dimensional visualisation:
The point of view of the projected images is fixed: The observer has to keep his
head in one position so as to not see the visual deformation of the virtual scene;
The observer's head is tracked: The point of view changes with the position of the
head to provide immersion of the eyes. The three-dimensional perception of the
virtual scene is thus more effective (see the paragraph on the perception of depth in
chapter 3 “Human senses'' of the treatise). The user can observe the virtual object
from different angles to perceive it better. These angles, however, are limited! All
advertisements are not to be believed completely! The constraints of 3D images are
such that the object cannot be turned beyond more or less 30 (a rough estimate).
Note: In the second case, where the head is tracked, if several users want to observe
a 3D scene at the same time, it would be necessary to show each of them a different
image and set up a system for separating the points of view (see section
The observer, whose head is tracked, should perceive the stationary object even
while moving the head. This is possible only if the location sensor is accurate enough
and the latency is very low. A good number of erroneous demonstrations have con-
vinced us of the complexity of the problem. A different location sensor or a data glove
can be provided to manipulate the virtual objects. In addition to the tracking of the
observer, the dimensions, the angle and the number of screens of the immersive desk
can be varied.
Consul, an immersive desk marketed by Barco, has two stereoscopic screens set
in an L shape, measuring 1.02m
1.36m, and 1.7m diagonally (see figure 11.8). It
supports a video input signal with a resolution of up to 1600
1200 pixels. The overall
Figure 11.8 Consul from Barco. (Illustration: Barco, with permission)
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