Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Commodity Passive Stereo Graphics Vikas Chowdhry Atul Nayak Jason Leigh

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Goal Allow users of Access Grid to immersively share 3D content

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Design Criteria Should be inexpensive for the solution to be feasible and replicable across the AG community.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Enter 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.

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

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Advantages of Passive Stereo Allows us to use DLP projectors. As compared to CRT projectors these are: –Cheaper. –Brighter. InFocus LP500

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Other Advantages 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).

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Constructing An AGAVE

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Recommended Hardware Specs Dual Processor Pentium III 750 Mhz or higher. Atleast 512 MB RAM.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Hardware Specs Graphics Card Should support Twin View –Tested With GeForce 2 MX. –Alternatives (also tested) Matrox G450. –Alternatives (currently being tested) FireGL4. Radeon. GeForce4 Ti 4600.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago System Software Linux (tried with Red Hat 7.2 and Suse 7.2). – Prefer fvwm window manager for Suse. – Any window manager for Red Hat.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Application Software Coanim –Collaborative Animator –application for viewing 3D content over AGAVE –provides a flip-book playback of 3D models –

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Application Software Coanim –Requires Linux/SGI OpenGL Performer – CAVElib – CAVERNsoft –

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago

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

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

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projector Alignment In order for the passive stereo to work, the images from the two separate projectors must match up on the screen. We usually stack projectors vertically as shown. A typical projector mount setup

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Polarizers Circular –Work better because light is circularly polarized. –Effect is not dependent. on alignment of viewer’s glasses. –Are more expensive. –Required for tracking.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Polarizers Linear –Less expensive. –Stereo effect gets diminished with movement of viewer’s head.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Polarizers We use velcro to stick polarizers in front of the projectors. Use this test pattern file to make sure the projectors are aligned. – GeoWallAlignmentImage.ppm.gz

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

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.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projectors Mount Rear Projection –Better utilisation of front space. –Ability to go closer to the screen without shadows disrupting the immersive experience. –Space required behind the screen.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Projection Screen Issues Standard projection screens do not preserve polarization. Causes ghosting. Experimentation has led us to use ``Disney black diffusion film'' (Dbd) for rear projection.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Tracking Tested “Flock of Birds” head tracking system. – tech.com/products/ flockofbirds/ EVL tracking research. –evl.uic.edu

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Cost Of Parts 1.InFocus 530 Projectors2 x $ PC with GeForce 4 Ti$ Rear Projection Screen$ Slide Projector Stand$ Paper & Plastic Glasses$ Polarizing Filters$ 70 Total Cost$ 14120

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Added Incentives Rob Gag ( ) sells Geowall bundle Contains –Projectors –Mounts –Road Case

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Going Beyond Goals AGAVE is reaching beyond its initial goals. Being used wherever portability and cost outweigh the need for complete immersion as represented by CAVE.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Geowall Consortium AGAVE is the basis of Geowall. Utilizes AGAVE to visualize the structure and dynamics of the earth in stereo.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Geowall/AGAVE at University of Michigan

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago The Mac AGAVE Created by Andy Johnson at EVL. –Being used to teach sixth graders scientific enquiry. –Meant to replace more expensive immersadesk being used till now. Details at: –evlweb.eecs.uic.edu/aej/ macagave.

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

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Stereo Photography –Used by geologists to document expeditions and sites in stereo. –

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Sites that have built AGAVEs Electronic Visualization Lab, Univ. Illinois at Chicago. The GeoWall Consortium. Dept. Geology and Geophysics, Univ. Minnesota. Dept. Astronomy, Univ. Minnesota. Institute for New Media Studies, Univ. Minnesota. Visualization and Digital Imaging Lab, Univ. Minnesota- Duluth. Dept. of Computer Science and Mathematics, Fond Du Lac Tribal and Community College. Northern Arizona Univ. Arizona State Univ. Dept. of Curriculum and Instruction, Univ. Minnesota. Eros Data Center, US Geological Survey (USGS). Dept. of Geological Sciences, Univ. Michigan. Media Union, Univ. Michigan. Geological Sciences, Indiana University, Bloomington.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Future Agave in a box – making installation easier. Add a Gyromouse TM /game controller for intuitive navigation. Camera based hand and head tracking Standardize specs.

Electronic Visualization Laboratory (EVL) University of Illinois at Chicago Future Make more applications available for AGAVE. Encourage people to build and deploy AGAVE where cost savings justify lack of immersion as compared to CAVE or immersadesk.

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