1. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall 101 Vaidya C. Atul Nayak

2. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Outline What is a GeoWall ? What are the components of a GeoWall? How does it work? Setting up the hardware. GeoWall software.

3. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall An inexpensive solution to view 3D data in stereo.

4. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall or AGAVE or C-Wall ? AGAVE : Access Grid Augmented Virtual. Environment (predecessor to GeoWall). Geosciences community embraced AGAVE and named it GeoWall. C-Wall in addition uses a 3D tracking system.

5. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWalls in Use

6. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago 70+ Walls since Jan 2001 June ‘02Sept. ‘02 40 70 Other Geosciences Integrated into Univ. Michigan, Minnesota, Wisconsin, Indiana and Arizona State curriculum- ~3100 students per semester. Deployment at SciTech Museum in Aurora, Illinois; Museum of Science and Industry in Chicago.

7. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall Components 1.InFocus 530 Projectors2 x $ 2550 2.PC with NVIDIA card$ 2500 3.Front Projection Screen$ 160 4.Projector Stand$ 420 5.Paper & Plastic Glasses$ 200 6.Polarizing Filters$ 70 7.Splitters, cables, etc. $200 Total Cost $ 8650

8. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Recommended Computer Hardware Specs Pentium III 750 Mhz or higher. At least 512 MB RAM. Graphics card –Should support Twinview –Recommended Quadro4 900 XGL GeForce 4 Ti 4600

9. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Use InFocus LP 530 DLP projectors. As compared to CRT projectors DLPs are: –Cheaper. –Brighter. InFocus LP530

10. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Screen Front projection –Stewart Film screen Corp –Coated with polarization preserving material – DaLite silver. Rear Projection –Experimentation has led us to use ``Disney black diffusion film'' (Dbd) for rear projection. –Tip : Do not touch screen – coating goes off.

11. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Passive Stereo Schematics Right Eye Left Eye Circular Polarizers

12. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Passive Stereo What is it? Two projectors are used for the single screen one for each eye's view. Differently polarizing filters are placed in front of each projector lens. Users wear polarizing glasses where each lens only admits the light from the corresponding projector.

13. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Advantages of Passive Stereo Polarized stereo glasses cost much less than the LCD shutter glasses used in active stereo. Less fragile (you can stop worrying about collecting the glasses after the show is over).

14. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Polarizers Two types of Polarizers Linear Circular Circular preferred. Place polarizers some distance away from the bulb. Holder– Use PCI Slots+Velcro to stick on projectors.

15. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Polarizers Circular –Works better because light is circularly polarized. –Effect is not dependent. on alignment of viewer’s glasses. –Are more expensive. –Required if you plan to use head tracking.

16. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Stereo Glasses Glasses to see stereo Linear or Circular, depends on Polarizer used. Disposable paper versions, reusable plastic and aviator style. Cost much less than the LCD shutters used in active stereo.

17. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Mount Front Projection –Easier to setup. –Cannot move too close to the screen as shadow causes loss of immersive experience.

18. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Mount Rear Projection –Better utilization of front space. –Ability to go closer to the screen without shadows disrupting the immersive experience. –Space required behind the screen. –Can use a mirror to bounce the light – to reduce distance behind the screen.

19. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Set up In order for the passive stereo to work, the images from the two separate projectors should match up on the screen. Projectors aligned when most of the left and right images (mostly in the central areas of the screen) overlap. Vertical disparity is more offensive than horizontal disparity. A typical projector mount setup

20. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Set up We use velcro to stick polarizers in front of the projectors. Use this test pattern file to make sure the projectors are aligned http://www.evl.uic.edu/cavern/agave/Geow allAlignment.jpg

21. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projector Alignment

22. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projector Alignment Vertical Disparity difficult to view compared to Horizontal Disparity Projectors alignment cannot be perfect as cheap projectors and improper polarization. Geometric Alignment of the two images is being done.

23. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago System Software Windows XP/2000. Linux (tried with Red Hat 7.3 and up, and Suse 7.2 and up). –www.redhat.com Any window manager for Red Hat. Prefer fvwm window manager for Suse. Get latest Drivers from NVIDIA site, www.nvidia.com. www.nvidia.com Linux use NVchooser.sh to get the Driver version.

24. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Application Software ImmersaView –Open Inventor model viewer for the GeoWall –The data can be a single Inventor model or a flipbook of models Screenshot of Immersaview

25. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Application Software ImmersaView –Requires Windows/Linux fltk (fast and light toolkit). Open Inventor http://www.coin3d.org

26. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Stereo Viewers Wallview –View Stereo images in Windows –Large images loaded fast –Can also use ‘Irfanview’ Viewer –View Stereo images in Linux –Multifile support and Slideshow. Other Software –Vis5D –Walkabout

27. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Interaction in GeoWall Can be use keyboard, mouse,joystick. Tracking can also be performed in GeoWall. YG and other software that runs on the CAVE can also be used on the GeoWall.

28. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Stereo Images Images can be taken in stereo using Stereo Cameras. Viewed using Viewer or Wallview.

29. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Tips for a good demo Buy both the projectors at same time, they will then age together. Sound card “Sound Test live” is recommended if sound is required. Carry an Extra projector. Stay away from the screen.

30. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall Web page

31. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Cost of parts 1.InFocus 530 Projectors2 x $ 2550 2.PC with NVIDIA card$ 2500 3.Front Projection Screen$ 160 4.Projector Stand$ 420 5.Paper & Plastic Glasses$ 200 6.Polarizing Filters$ 70 7.Splitters, cables, etc. $200 Total Cost $ 8650

32. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago The Mac GeoWall Created by Andy Johnson at EVL. –Being used to teach sixth graders scientific enquiry. –Meant to replace more expensive immersadesk being used till now.

33. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago GeoWall in Chile GeoWall was part of the demos at the Internet2 conference in Chile. Proof of “Pack and Go” stereo.

34. Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Questions?