3. Set Up Procedure
The system requirements were described in TODO : Give link. Connect your monitors, keyboard, mouse and splitters. Make sure that Twinview works and for now set up the desktop for horizontal span. Here is a brief description on how to get horizontal span on Windows and Linux for the Nvidia cards. Windows 2000/XP: 3. Click OK. Linux: 1. The /etc/X11/XF86Config-4 file controls how the display should look. Please look at the README file that Nvidia provides. The following is a chunk out of this file relevant to setting up Twinview. Section "Screen" Subsection "Display" Option "TwinView" EndSection You can download an example XF86Config-4 file here. This file is configured to run in 'Clone mode' where both your monitors will show the same desktop instead of the desktop being stretched across. Change the 'TwinViewOrientation' to 'RightOf' (or 'LeftOf') ; restart the Xserver and you should see the desktop stretch across the two monitors.
This step involves the mounting of projectors and placing the screen. There are two projection techniques: TODO: Give a picture of the projection systems here.
If immersion isn’t absolutely necessary, and stereoscopic 3D is the main goal, then front projection works effectively. Rear projection systems are a little more cumbersome to set up and more expensive, but the display is more compelling than front projection. Again, there are two ways you can mount the projectors: 1. Table Mounted projection. TODO: Images for projector mounts go here. Ceiling Projection: In this case the projectors are hung inverted from the ceiling and The projectors are usually hung from a slot in the ceiling to hold them, so that they face the screen.
Mount projectors on a metal (or fire treated wood) shelf 10" x 2 feet, side by side with the lenses as close together as possible, with their horizontal crosshairs aligned and their vertical crosshairs parallel. In this case since both the projectors are inverted as seen from the screen the options in the projectors must be changed to produce inverted images so that they beocme straight when projected on the screen. This can be done by using display controls in the projectors. Table Mounted Projection TIP : Set the brightness on your projectors to 50%. 3.3 Split signal from the Graphics card.
3.4 Set Up Polarizers The polarizers need to be setup next in front of the projectors so that the light from the projectors gets polarized. Stick the polarizer on the projector using velcro. In our early experiments we used duct tape or paper clips to fix the polarizers directly on the bulb; it's safer to stick them at least 5 inches out in front of the projector bulb. The pictures below illustrate the step-by-step technique to put polarizers together. TODO: Images 1: Different parts of the polarizer. Image 2: Connect all the parts together. Image 3: Polarizer attached to the projector.
The alignment of the projectors is next and is the most important
and time-consuming part of the assembling process. Download this image
as a jpg
or as a ppm.
The projectors are said to be aligned when most of the left and right images geometrically overlap on the screen. It's almost impossible to get every part of the images to overlap perfectly since the projectors don't have shift lenses in them; so concentrate on getting the central portion of the image to overlap. In particular, get the words 'GeoWall Alignment', the color bands and at least one of the words 'Focus' to overlap. Vertical disparity between the left and right eye images will hurt the viewer more than horizontal disparity in the alignment;so try to avoid vertical disparity. You can use the knobs on the stand or the mount to make the projectors throw light on The projector has adjustments for adjusting the focus and the zoom on screen. This feature can be used in alignment to a great extent.
The Final set up of the geo Wall should look somewhat like the one shown below. After this applications can be run to perform various tasks like data visualization and solid modeling etc.
|