The Graphics Lab

St. Olaf College

Feel free to contact Aaron Etshokin at Aaron.Etshokin@gmail.com for any questions regarding the setup of the lab, especially the GeoWall.

• What's in the graphics lab:
• Nice computer with an nVidia Quadro GPU (Graphics Processing Unit)
• Wide silver screen (16 feet by 8 feet)
• Two DLP projectors
• Dolby Digital 5.1 capable receiver
• DVD/VHS player
• Polarizing filters/polarized glasses

Different physical display layouts

It is easy to change the physical display properties with the graphics card we have installed on the computer. There are many different display orientations but we've never had to use anything other than horizontal span (the desktop is 2048 x 768), clone (both projectors display at 1024 x 768 overlaid on one another), and single display (one monitor receives no input, and therefore just emits blue). We'll now discuss which of these orientations are necessary for certain applications.

The easiest way to quickly change the physical display properties is to click the nVidia icon in the Windows system tray and select "nView display settings". This menu contains the different afforementioned display layouts.

• Horizontal Span
• Horizontal span is used to display stereo pairs and to view stereo movies.
• Clone
• Clone mode is used for stereo gaming and some other graphics applications that the nVidia card renders automatically into stereo.
• Clone mode is also the easiest way to align the projectors because clone mode clones the same desktop, which allows a person to see exactly where the projectors aren't aligned perfectly.
• Single display
• We don't use single display too often. The main problem is that when single display is turned on, one of the projectors doesn't receive input, and therefore shines only blue, which can dominate the other monitor. If we could pic mute only one of the projectors, this orientation would be used more often but currently this is impossible.

Viewing stereo pairs with the graphics lab

It's simple to take stereo pairs with any digital camera. The St. Olaf Graphics Lab can take any two stereo pairs (if they are taken properly) and recreate a three-dimensional representation of the scene. This section will assume that the stereo pairs have already been taken and are ready to be displayed.

The computer used in the graphics lab has one tools to view stereo pair stills: WallView, an open-source software package with a simple user interface. Here is a simple tutorial for viewing a stereo pair:

1. Start WallView: Start Menu->Programs->wallview
2. Add data set: You will now be at a screen asking for input of stereo pairs data sets. Click "add set" to add a stereo pair to the current data configuration file. The program will then prompt you to select the left eye file and the right eye file. Since you have stereo pairs ready, select those files for the associated image. Then hit "okay".
3. Show the data set: You should see your stereo pair listed in the data set table. Select the data set you just added and then hit the "show" button to display the pair. You should now see the stereo pair! If it didn't work, make sure you are currently in span mode.

Other Applications

• Axiom Molecule Viewer:

  The Axiom Molecule Viewer allows you to visualize any molecule in 3D stereo. To access the viewer, go to Start -> Programs -> Axiom Discovery -> Molecule Viewer. When the program opens, it is not showing any molecules. To display a molecule, you must drag and drop it onto the Axiom window. There are some sample molecules in "C:\Program Files\Axiom Discovery\Sample Files" if you're looking for something. Otherwise there are many web sites that deliver PDB files for molecules (e.g. proteins), and these work well with Axiom. Molecule files with registered file extensions, like .PDB, can also be opened in Axiom by double-clicking the file's icon.

  To enable stereo in Axiom:

1. Set the display to be Horizontal Span mode.
2. Maximize the Axiom window.
3. In the context menu, visit "Renderer Properties", then click on the "Stereo Views" option on the left.
4. Click on "Cross Eyed" (you may need to click on "No Stereo" then "Cross Eyed" if it doesn't work the first time). The angle and separation should be configured on-the-fly to what appears appropriate (at the very least, the angle should be lowered).
• Partiview:

  Partiview is a universe exploration program. To open Partiview, run one of the batch files in "My Documents/software/partiview". Each of the batch files loads a different dataset that is of some sort of interest. "3-D_Constellation_Modeling.bat" is a good place to start: it displays a representation of the stars in Orion, with lines drawn between the stars.

  Once Partiview is started, there are three possible types of movement within the virtual universe (these options are also available via a menu at the top of the Partiview window):

1. Orbit [hotkey: 'O']. This is the default when Partiview opens. Click and drag on the screen to begin rotating the camera.
2. Translate [hotkey: 'T']. Click and drag on the screen to translate the camera's position.
3. Fly [hotkey: 'F']. Right-click and drag to "fly".



To enter stereo mode:

1. Configure the graphics card to be in Horizontal Span mode.
2. Maximize the Partiview window.
3. In the command line in Partiview (just below the menus), type "stereo cross", and press enter.

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