Talk:Cave Automatic Virtual Environment

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Contents 1 Image 2 Definition 3 Commercial Systems 4 Eliminating the rear-projection hotspot? 5 Shutter or polarized glasses for CAVE stereoscopy? 6 What shutter-glasses screen refresh rates are used? 7 Home Cave Systems?

[edit] Image

Can anybody add images to CAVE article ? . Thanks in advance.

[edit] Definition

I've worked with CAVEs before, and the acronym has always stood for 'Camera Array Virtual Environment'. I don't think CAVE Automatic Virtual Environment even makes sense. Can I get some help with this? Bigdavesmith 12:35, 12 May 2007 (UTC)

"Camera Array..." would be some other use of the name CAVE. The VR system described in this article has nearly always been the CAVE Automatic Virtual Environment, at least since Cruz-Neira et al "The CAVE: Audio Visual Experience Automatic Virtual Environment," Communications of the ACM, June 1992 (the "CAVE Audio Visual Experience" was an alternative expansion that never caught on). My understanding has always been that it was actually a backronym to fit a nickname, which is why it may sound bit odd. (The Plato connection was just a bit of luck. Also, prior to the CAVE name, it was briefly known as the "Pocket Cathedral".) --Davepape 05:39, 13 May 2007 (UTC)

I can deal with that. Still, I spent time working with a CAVE system, as in 'Camera Array Virtual Environment', and I see no such article at Wikipedia. Perhaps it would be worth mentioning something in this article, creating another article, or redirecting. Currently, a search for 'camera array virtual environment' brings up the HIVE project at Miami University. I think this page is a closer match than that one. I'm not going to make the changes myself, since I'm both a new editor, and not an expert on the topic. If you or anyone sees fit, please do. It is also possible that my group just improperly understood the acronym, but...there were quite a few of us in quite a few locations! --Bigdavesmith 19:20, 16 May 2007 (UTC)

[edit] Commercial Systems

Other than "if you have to ask you can't afford it" I've been unable to find a price for a commercial CAVE system. —Preceding unsigned comment added by QuantumG (talk • contribs) 01:44, 6 November 2007 (UTC)

This thing was on The Outer Limits (new version) one time.151.204.23.96 11:17, 10 November 2007 (UTC)

[edit] Eliminating the rear-projection hotspot?

How do CAVE designers deal with the intensely bright hotspot caused by using a rear-projected image? If the viewer is in a position to see both the projected image and the projector behind the screen, the projector lens assembly typically produces a blinding white spot that moves around as the user's viewing position moves, due to the projector lenses not being perfectly transparent at intense light output levels and light randomly bouncing around reflecting off the interiors of the lens assembly.

Is there a proper solution to this problem? Are projectors available for CAVEs that are designed to have minimal extraneous light output? A more opaque screen may help to blot out the hotspot but at a loss of overall brightness and focus. Perhaps close-fit masking around the frame of the output image can help to reduce the hotspot? DMahalko (talk) 19:59, 4 January 2008 (UTC)

[edit] Shutter or polarized glasses for CAVE stereoscopy?

There isn't much discussion in this article of how stereoscopy is projected into the CAVE space. I'm a little mystified how polarized glasses might work in a CAVE, since it is not possible to keep the polarization axis aligned across three sidewalls and a floor. At best, alignment is possible only across the three sidewalls, but the phase of the floor will change when the viewer turns their head by 90 degrees from left to right. Looking down into a corner of the CAVE, say bottom left or bottom-right, leads to the polarization rotating about 45 degrees out of alignment for all three screens viewed, which will result in severe cross-polarization bleeding and likely a total visual mess.

In general I would assume polarized glasses only work for single-screen stereoscopic effects, where the viewer is not likely to ever be viewing the screen from an off-axis or rotated angle. It appears that all CAVEs are required to use shutter glasses. Left/right frame sync would not be affected by rotation or off-axis viewing of the screens. DMahalko (talk) 17:00, 5 January 2008 (UTC)

[edit] What shutter-glasses screen refresh rates are used?

I know from my own home experiments with shutter glasses, that the screen framerate must be doubled for shutter-glasses to work properly. A regular CRT typically operates at a minimum of 60Hz to minimize flicker. For shutter glasses this rate is cut in half by the alternate framing for each eye, and requires the actual screen refresh rate be doubled to 120Hz to give the appearance of running at 60Hz.

But on a normal CRT, flickering is still noticeable in the periphery of vision at 60Hz and can cause headaches over time. Higher framerates are more desirable and reduce apparant flickering, such as 75Hz, 85Hz, or 100Hz.

For shutter-glasses, such framerates push the limits of what even the best video cards are capable of doing, requiring a refresh of 140Hz, 170Hz, or 200Hz. I know if just a handful of video cards capable of 140Hz and none that can do 170Hz.

So how do CAVE designers prevent their users from getting headaches due to low framerates? DMahalko (talk) 17:07, 5 January 2008 (UTC)

[edit] Home Cave Systems?

I'm assuming these things are too expensive for all but the very wealthy. So were computers in 1970. When should we expect to see cave systems in the home? —Preceding unsigned comment added by 72.67.35.214 (talk) 06:24, 19 May 2008 (UTC)