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Graphics Software

University of Illinois uses a Cluster for Immersive VR 123

It seems the folks down at the University of Illinois at Urbana-Champaign have created a 6-sided CAVE like system called ALICE. But, instead of running it off of a SGI Onyx, they've developed a distributed environment for visualization called Syzygy. Slap a few computers together and make your own holodeck!
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University of Illinois uses a Cluster for Immersive VR

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  • Emersive? (Score:2, Funny)

    by Ravagin ( 100668 )
    Is this, like, transcendentalist VR? Far out!

    Or maybe it has something to do with emery; but how a powder generally used for grinding and polishing fits into VR, I don't know.

    Now I'm going to read the article.
  • Comment removed based on user account deletion
  • Great! (Score:3, Funny)

    by darkov ( 261309 ) on Tuesday December 18, 2001 @06:27AM (#2719019)
    This should make for some stupendous pr0n! Come on all you vouyers, start stringing those polygons together.
  • This is a delightfully holodeck system, but I find it hard to believe it can convinve you you aren't standing in a box. If I recall, the holodecks also used force field treadmills or some such to control your movement. That's still a ways away, I bet.
    • If I recall, the holodecks also used force field treadmills or some such to control your movement.

      I hate to be the one to tell you this, but they don't use force field treadmills. They don't actually really exist. It's only a tv-show (and/or a movie).

      Also, there's no santa claus.
    • Holodecks are also supposed to use full motion, photo realistic holography. This sounds more like surround television. Impressive but not exactly Star Trek grade.
      • Not to be a bigger geek, but actually I think it had something to do with the replicators also. The food they ate in the holodeck was "real", the women they fucked "real", etc. It had mass and was authentic.
    • But then I got a girlfriend.

      The reason they can't convince you you're standing in a box has to do with the inherent boxness of the space in which you stand.

      Bigger TV == Still TV

      TV != Life
    • I don't see that happening for a long, long time... if ever. The devices seen in the movie "Strange Days" are probably more within the realm of feasablity. Unlike the holodeck, which has to accurately simulate all aspects of the real (or unreal) world as realistically as possible by manipulating matter and enery directly, it would be much simpler to "hack" into someone's brain and recreate the appearences and sensations of a reality within the confines of one's mind. Besides, it's less likely they could tell it wasn't real than if they used their own physical sensations to make the determination for themselves.
  • This is one step in the right direction. Big things like these show you what commodity products of the future will be like.
  • by Warvi ( 544623 ) on Tuesday December 18, 2001 @06:39AM (#2719057) Homepage
    See their HOWTO for building up your own setup at

    [uiuc.edu]
    http://www.isl.uiuc.edu/ClusteredVR/szg/doc/Para me terExamples.txt

    That seems like pretty doable by any geeks with enough boxes.

    That would say if the 3D immersion has any usability to it at all, it will be in common use in 10 yrs. It might become the next big thing in living rooms like TV became 40 years ago.

    However, what makes a new technology break through is not what it enables, but what you get with it. TV would have had no use whatsoever without the television programs made to be watched with it. Computers only broke through when there were programs for it.

    Umm, I sense a great opportunity for all people who can really do great 3D graphics.

    Not to mention what I already said about getting 3D GUIs off the ground at

    [slashdot.org]
    http://slashdot.org/comments.pl?sid=25035&cid=27 18 945
    • by Mike Connell ( 81274 ) on Tuesday December 18, 2001 @07:09AM (#2719132) Homepage
      That seems like pretty doable by any geeks with enough boxes.

      #include "Wry smile.h"

      6 linux boxes and the clustering software is only half of the problem. The harder half is 6 or 12 videoprojectors (or more!), the mirrors and the (back) projection surfaces for the CAVE. Add in the tracking hardware (cost and complexity (ie EM interference)), and you have a lot more work to do.

      Don't get me wrong - it excellent that it's feasable for a department to install their own fully immersive VE without an Onyx and a team of engineers, but you'll still need a team of grad students, builders and time.

      Also dont forget that you need a *big* room for one of these too - say you have 2m high surfaces, you basically need 6-8m of vertical space once you include the space for the projectors and mirrors for the top/bottom 'walls'
      • It's easy to play the devil's advocate, but I think there's more poewr for enthusiasm than downplaying here.

        The harder half is 6 or 12 videoprojectors (or more!), the mirrors and the (back) projection surfaces for the CAVE. Add in the tracking hardware (cost and complexity (ie EM interference))

        Their source is GPL'd; it could be modified to use standard or flat monitors in a downsized setting.

        you'll still need a team of grad students, builders and time.

        Same goes for developing operating systems. [kernel.org]

        How many /. readers are grad students and builders, I leave as an exercise for the reader to wonder.

        you need a *big* room for one of these

        Unless you downsize it. How many of us have spare space for wondrous technical projects...

        The electronic (wall)paper is being developed at least by IBM and, err, was it HP (my memory fails me here and I'm too lazy to check /.'s comprehensive archives on all the stories of this subject). Say it will hit market 5 yrs from now; you'd still have 5 years to make a product out of this to get it to market by my wildly suggested deadline of ten yrs from now.

        All that is needed for this breakthrough is all that work to create the usable content, just like DVD's need movies to sell.

        I am sure some of us are willing to put together the effort in small groups of friends interested in this achievement. Just for the fun of it!
        • Their source is GPL'd; it could be modified to use standard or flat monitors in a downsized setting.


          Sure, only the result would be a total waste of effort, not much more immersive than using a single monitor.

        • Noting that this is clustering software for a *CAVE*.

          1. You can't use "standard or flat monitors" in any form of "downsized setting", because unless you are 6 inches high, it's not going to be immersive. You can't stand in the cubic space formed by the faces of 6 monitors, flat or not, unless you are a person of very very small stature. Even if you can find a 6" high person to get in this contraption, they'll probably get fried by all the EM radition & heat after a few minutes, so you'll need a supply of these people...

          2. Bringing up kernel.org looks like blatent karma-whoring - it's completely irrelevant. The problems you missed, and which I pointed out to you in my first post are the physical problems - you have to build an immersive space environment - a physical one - out of wood. You can't email an 12 foot high wooden structure around on the internet you know!

          3. (You need a big room for this) "Unless you downsize it". Oh sure, if you can also "downsize" your users. You have to build something that you can get inside of. There's a limit to downsizing - at the limit is your body!

          If you're only going to use a powerwall or something it's a different kettle of fish, and you can just hook up WireGL or something of that nature with what I expect will be a lot less effort.

          So as I attempted to point out (and obviously failed) in my first post - there are real physical engineering problems that make the construction of your own CAVE environment much much harder than downloading some code and playing with the configuration files.

          0.02
          • 3. (You need a big room for this) "Unless you downsize it". Oh sure, if you can also "downsize" your users. You have to build something that you can get inside of. There's a limit to downsizing - at the limit is your body!

            Really, it doesn't have to take up *that* much space. I've worked in the CAVE before, and while it's somewhat large, there's no reason it couldn't be made smaller these days, given that three-gun CRT projectors are outmoded, and with a single gun projector you could use much smaller mirrors. Make the walls 6' high, and you'd need a room maybe 15' by 15', perhaps 20' by 20' to get the job done. And the ceiling needs to be maybe 8' tall, given some planning. (the CAVE system doesn't have a ceiling surface, but it has a floor - there's a projector pointed straight down via a mirror).

            Granted, the 12 CPU Onyx2 (named Cassatt) takes up some room... but that is physically located in a different room in the Beckmann setup, and video is piped in.
            So basically you need:
            • 4 LCD projectors, at a minimum of $1200 or so each for cheesy ones.
            • 3 rear projection surfaces - since we're using cheap projectors, you may as well use white bedsheets attached to a homebuilt wooden frame
            • 3 or 4 small-ish mirrors, unless you've got room to put the projectors all around the area.
            • (the biggie) Lots of CPU, and software.
            Thankfully, the software mentioned in the article is freely available, so that takes some cost out of the problem. Now you just need a minimum of 4 graphics pipes, say $200/each GeForce2 or whatever's available, and machines to put them in. Perhaps with some nice fast interconnects - gigabit ethernet will do in a pinch, there isn't such a need for things like Myrinet [myri.com] anymore, although Myrinet is doing some truly wicked things these days (2+2 gigabit full-duplex networking!)

            But I digress. As you can see, it's doable.

            • So basically you need:
              • 4 LCD projectors, at a minimum of $1200 or so each for cheesy ones.

              Cheesy is right. I imagine for that money you get 800x600 resolution. A 1280x1024 projector is thousands more. But anyway...

              • 3 rear projection surfaces - since we're using cheap projectors, you may as well use white bedsheets attached to a homebuilt wooden frame

              You want something that won't flap in the breeze. To get any decent focusing you need F-L-A-T.

              Skip the floor projection, I guess - it would require a hard screen - think mid-five-figure range for quality, I dunno how cheap you could go. The sides could perhaps use latex, for which the big boys would still want at least four figures per each ... guess it would depend on size. I'm not sure offhand what you could build on the cheap, but I strongly suspect that bed sheets wouldn't cut it.

              • 3 or 4 small-ish mirrors

              ...and mounts which let you adjust at least one angle - you don't want to hard-code this or your final adjustments will Not Be Fun. Also, I don't know if this is critical for a "budget CAVE", but for our VR center here we have front-silvered mirrors - for obvious-I-hope reasons.

              • Lots of CPU, and software.

              Yeah. And not just CPU but lots of motherboard bandwidth - you'll probably want 66MHz and/or 64-bit PCI for the GigE, and the same (or AGP4x) for graphics.

            • I am fighting and losing a battle with my "last word" neurons :-)

              As you can see, it's doable.
              "CAVE on the cheap" is clearly doable: it's already been done with the NAVE, and the "Wedge".

              Really, it doesn't have to take up *that* much space.
              The article mentioned a 6 sided CAVE. It's the floor/ceiling setup that require the extra vertical space. If you dont have them, of course you need less space.

              0.02
      • Also dont forget that you need a *big* room for one of these too - say you have 2m high surfaces, you basically need 6-8m of vertical space once you include the space for the projectors and mirrors for the top/bottom 'walls'
        Originally CRT monitors were the same way -- needed lots of room in the back for the projection. Now there are corrective CRTs that allow for the same screen sizes in the same quality and the same resolutions with less depth needed. I figure that application to this field would work well.

        Eh, that or building some bigass plasma screens. ;)
    • This is the second post I've seen that assumes you'd project 3d graphics onto this thing. What about video?

      I'm sure existing 360 and 180-degree camera technology, plus some clever DSP/image-processing could get you immersive live environments too.

      Visit the space-shuttle. Swim the great barrier reef. Be on the frontline for war reporting.
      • You could - it just wouldn't be very immersive. With a 3D environment in a CAVE you dont just stand in the centre, you actually walk around a bit. If a virtual object is in the way, you might lean around it, or crouch down to look under it, just like in real life.

        This means that the views have to be created based upon where your head is - which is why at least one person will have a head tracker, if you dont have this, it doesn't feel immersive, it just looks plain wrong.

        Of course, you could keep your head in the centre, and not move it but it kind of ruins the point. Also keep in mind that I am taking 3D stereo display for granted here, but it's not so easy with real cameras, especially if you want 360 degree recording.

        Often people stick video images onto 2D objects (like the front of a virtual TV) within the 3D environment. That's pretty cool :-)

        0.02
      • Be on the frontline for war reporting.

        Just what we need. Geraldo transmitted around the world in 3D!

        On that thought, though, there are a number of TV shows I'd fear to see in an immersive environment. Jerry Springer comes immediately to mind....
    • ...if the 3D immersion has any usability to it at all, it will be in common use in 10 yrs.

      That statement has been true for at least the past 20 years.

      Unfortunately, there isn't much benefit for most people from a 3D interface because they don't see or think in 3D.

  • ...why is it called ALICE? Is it a deliberate attempt to confuse people who already relate ALICE to the ALICEbot [alicebot.org]? Is ALICE simply just a very adpatable acronym? Does ALICE the acronym deserve an acronym to describe it's acronymity? Adaptable Language In Crappy English, perhaps?
    • I rather suspect that ALICE is a common acronym due to Alice [of Wonderland fame]. Ever since Charles Dodgeson, a mathmo himself, wrote it that book has been a favorite of geeks world-wide.

      See for example: quark
    • Is this the same ALICE that DARPA was working on i didn't read the article not will i get around to reading it but their was a 3d rendering/cad software that DARPA and Michigan university. It was a new type of CAD that involved a scripting language and physics engine in it... i know now that most all CAD software MicroStation AutoCAD involve scripting and physics but this was about 5 or 6 years ago it came out
  • As far as I know, we have had a Cave down at the U of I for several years? I have never been in it, but it IS supposed to exist. So what is special about this? P.S. If you are ever down here, stay away from Beckman! Many young lads enter, few are ever seen again...
    • UMich has one too. It's very cool, but the computers to support it are kept on raised flooring with monks that tend them. The cool thing about this project is that it uses commodity hardware as much as possible.

      (Hey Andrew, remember that conversation we had about synchronizing the output of several 3d cards? Looks like they did it!)
    • Yeah, the Cave is still there, on the third floor. The other cave (ALICE) is in the basement.
    • Yes, there's a Cave in Beckman. I've been in it several times and it rocks (though physically turning your body when you're playing Quake takes some getting used to... be prepared to die many, many times at first).

      A buddy of mine was an RA for the Cave for a while. The CS department occasionally offers a Cave programming class.

      I believe the Cave folks have free open tours one day a week. You just have to sign up.

      As others have pointed out, the advance here is that this new system runs on commodity hardware. You will indeed still need some expensive stuff to make it work. The standard Cave uses two LCD projectors (if you haven't priced these projectors, cheap ones cost $1,500, good ones cost $5,000 and up) for each wall to get the 3D effect. You use LCD shutter goggles so each eye sees the image from the appropriaate projector.
  • the moniker of "slap a few computers together and make your own" is a bit off. there are a ton of details and specalized software needed to make one. Granted, I think it would be really cool for a community college or a high school to make (where does one come up with 6 lcd projectors for dirt?)

    cince it's slashdotted, anyone know of any projects like that that actiually release all the software used to make it work?
    • Re:roll your own (Score:3, Informative)

      by Anonymous Coward
      The Cornell Theory Center (www.tc.cornell.edu)
      has a 3-wall cave setup that uses 3 off the shelf dell workstations running w2k and software from vrco.com. Seems to Just Work; I played quake on it a couple months ago.
    • Stereo options (Score:2, Informative)

      by Elazro ( 532810 )
      Unfortunately, you can not use 6 LCD projectors if you want to view stereo. There are two options for stereo viewing that are considered: passive and active stereo. The latter requires special shutter glasses (which come in prices of $20 to $600), and the former just requires simple polarized glasses like you get at a 3D Imax.

      However, LCD projectors can not do active stereo. The projector displays the left eye view and the right eye view sequentially, and the active glasses (which must be somehow synchronized to the projector) block the right and left eyes sequentially. So at any given time, one eye is viwing an image, and the other sees pure black. If the refresh rate is too low, then the stereo starts to become flickery. And uncomfortable to the eyes. You can view stereo with a 60Hz display, but for most people, five minutes is about all they can stand. At 96Hz, one can view stereo comfortably for quite a while. 120 hz is even nicer.

      From what I understand, LCD panels can't achieve these speeds (something to do with the energy requirements, and especially the cooling requirements, going up exponentially with Hz) One can use CRT projectors, or DLP projectors (I saw such a CAVE at EVL in Chicago, birthplace of the original CAVE)

      With passive stereo, LCD's can be used - basically you just shine 2 projectors fitted with polarized filters at each screen, spend about a week aligning everything, and you're ready to go (special lenses may be needed so that alignment can actually succeed)

      Now, there actually are some other options - the least interesting one is anaglyphic stereo (red/blue glasses). We'll let that one slide.

      However, many new auto-stereoscopic technologies (glasses-less) are being developed.

      There is lenticular - based on the same principle as those doodads you used to get in cereal boxes, where the picture would change when you rotated the thing. Now those things only had 2 images, and you had to rotate it 30 degrees to change the image. But you can make 'em so fine that each eye sees a different image. Put a display behind it, and you have autostereo. see here [nyu.edu]

      One of the funkiest methods I've heard of being tried is to use pupil tracking. To understand this, you need to know that the eye is a very low resolution 'camera' for the most part. However, in the dead center of the retina, there is an extremely dense set of receptors called the fovea. It covers only about 1-2 degrees of arc, and this is where your eye picks up pretty much all of the detail.

      Now, if you use pupil tracking (which can be done without the viewer having to wear any special equipment), then you can determine the region of the screen each eye's fovea is covering, and draw the corresponding image there. I haven't found an online reference to this yet, but I think it's a cool, if not a little difficult, solution to autostereo.

      -matt

  • The Australian National University has been working with similar concepts for about 4/5 years now. See their Wedge [anu.edu.au] VR system. Not a CAVE by any means, but it can easily be extended to support more "walls".

    Most importantly, it is a display of what can be achieved with off-the-shelf PC level hardware. Even the projector system is a lot cheaper than that used by the CAVE systems. And it uses Linux too!

  • No entry found for Emersive in the dictionary.
  • Real Quake Arena (Score:2, Interesting)

    Wouldn't it be cool if someone built an 'arena' which matched a level from quake. People would ware a standard VR helmet, and a portable PC, and 'run' around the real areana, and be able to touch the walls, but only see whats presented them through the VR headset. There would be some sort of radio triangulation, which would track everyones position within the room, and relay the information back to a main server....- This would put Qzar/Laser quest to shame!

    T.
  • Wow! Open sourced 3D cave software! Now we just need to port over the matix, star wars, etc. and build one in my living room.
  • ITYM "Immersive". If "Emersive was a word, It would probably mean something to the effect of "coming out of".
  • or, slap a few spell-checkers together and call it immersive.

    they call them editors for a reason.

  • NAVE (Score:2, Interesting)

    by davechen ( 247143 )
    They have a similar system at Georgia Tech, called the NAVE [gatech.edu]. It's a three sided, small scale cave. The interesting thing about it is that they did it on the cheap. Just a bunch of students with hammers and nails to put it together. I think they said it cost 60 grand total in parts.

    The PC's driving the walls were running Windows. So when we got a demo, they rebooted the machines first off. They said to clear out all the OS cruft. The synchronization between the walls was not very good at times. I'd say large fractions of a second. Thats the one thing a big SGI gets you, really tight synchronization between the walls.

    dave chen
  • I'm not sure that emersive is even a word. However, immersive, adj. (immerse, verb: to place an object within something else), in this case, means to place the computer user within the computer interface.

    If emigrate/egress (to leave) is the opposite of immigrate/ingress (to arrive), then maybe emersive means to place the user outside of the interface.

    Is there an inside joke or other good reason for using emersive? I'm not really complaining about spelling as much as "WTF does this confusing term really mean?" Really, does anyone have a story for this or is it just a speling mistake?

    • Jesus dude, if every time you see a spelling error you decide to assume it's some word you're going to have a real hard time living in this imperfect world! The typo and the correct word were even phonetically similar!
      • The real problem here is that technology is hard to understand, and the people who can understand it are too few to pay for it. This creates the need to *sell* it to idiots and dummies (like in the books) or business suits who don't even care about the technology.

        Cutting to the chase: the sales-weasels of high technology (Which the UofI and NCSA have become in the wake of NCSA Mosaic's effect on the WWW) like to coin meaningless words to name their projects so that people who aren't capable of understanding the technology can still recognise it. What I care about is when people lampoon this practice by creating a silly name with some kind of inside joke for the people who *DO* understand the technology. I was just fishing.

  • Virginia Tech [vt.edu] has a CAVE for VR too. The use it for everything from doing research to well... a little gaming (after all it never hurt anyone). If your interested more information can be found here [vt.edu]. They have numerous featured projects, click here [vt.edu] if your interested.
  • by john@iastate.edu ( 113202 ) on Tuesday December 18, 2001 @10:14AM (#2719698) Homepage
    ISU has probably the premier researcher in this area, Dr. Carolina Cruz-Neira. Here's some info on the environments at ISU: C6 [iastate.edu] and more... [iastate.edu]
  • CU recently opened a similar system [colorado.edu] as well. It's a three-sided "immersive visualization environment." Not quite as cool as the CAVE, but good. Nice SGI computers running it as well. My friend who has seen it in stereo mode says it is quite nice. I want to try Quake in it.
    • Hey, would this be The Matt who would know who I am? Or is this another Matt? If it's the former, good to see you on Slashdot. If it's the latter, nevermind.

  • Post Tramatic Stress Disorder treatment [google.com] - The cheaper it is the more that can be helped sooner.
  • Synchronizing those beast must be a @$$#. Trackers are also important. For a really immersive environment you basically need to respond to the user within 2-3 frames (MAX). I'm working at U of Alberta (Canada). We're running Onyx 2 with 6 processors (it has a fiberoptic connection to our supercomputer - 128 processors/ I think between 512M - 1Gig Ram/processor). 3 screens refreshed at 60 frames a second (although in a real 3d mode they're effectively refreshed 30 times/second/eye). Not only do you get it to fill almost all of your vision, it also LOOKS 3d.
    As a side note. I've talked to one of the profs in charge of our CAVE. He plans to write a game for it in his grad level VR class. (I couldn't get in that - it was allready full - I guess there is always next year). The possibilities are endless. How would you like to play a first person shooter where you have a sensor in the gun that tracks where you're actually poining? As well as tracking where you're looking at, (movement is always difficult in a CAVE environment), optical tracking that can recognize the 3d shape of your body so when you duck - you duck! Enough processing power to easily calculate whether the incoming ray/bullet/whatever intesected with your body in realtime. Nearly unlimited memory for levels/details. Possibly even sattelite connection to another CAVE system to make it multiplayer!
    Anyone drooling yet?
    • Possibly even sattelite connection to another CAVE system to make it multiplayer!

      Remember your physics ... the speed of light ... going to and from a satellite adds quite a few milliseconds to your latency. Latency is bad for FPS (and in this case we're talking really first-person) games.

  • The article sort of makes it sound like this is groundbreaking work for UIUC.
    UIUIC, if I'm not mistaken, is the location (or one of the locations) of the National Center for Supercompuing Applications (NCSA anyone?). They already HAVE a passel of really funky VR & immersive environments.. CAVE, versadesk, that funky classroom....
    So they did a 6 sided cave instead of the old one (3 or 4? I forget if the floor was done or not). I mean, it's great news.. and using linux is cool.. but really... It's interesting, not groundbreaking.

    As for those saying 'But they will need good synchronization and trackers'. It's NCSA. They have lots of this gear already.. they already have a cave, remember.

    Dammit. I was only a few minutes away from there on my travels once.... I wish I could have gone for a tour.
    • Well, IIRC, this isn't an NCSA project, it's being run by the Beckman Institute. They do have the advantage, however, of being able to run upstairs and talk to the NCSA people who've been doing this stuff for quite a while now (and are located in the same building).

      I learned CAVE programming on the CAVE at NCSA; I hope I get the chance to play with this one some! (Not holding breath)
  • by Junior J. Junior III ( 192702 ) on Tuesday December 18, 2001 @12:21PM (#2720543) Homepage
    He originally wanted to name his company [atari.org] "Syzygy"...
  • To recreate stereo vision, it actually is more appropriate to utilize non-Euclidean geometry. In this specific case, an infinite number of parallel lines go thru a single point. Does anybody know if this system uses such? It would require a fairly massive refit to standard graphics programs.
  • Cool. We actualy have the first installed TAN cube in the world here at KTH (Royal Institute of Technology) Stockholm, Sweden. Ours are feeded by two SGI Onyx 2000's which each have 3 pipelines each feeding all 6 projectors.

    You can see the pictures of it here:
    http://www.pdc.kth.se/projects/vr-cube/photo-galle ry.html [pdc.kth.se]

  • MicroVision [mvis.com] has the right idea in advancing the state of the [commercial] art in retinal scanning displays.

    CAVE, while a nice hack, is really a big waste of time, space, and money, when compared to the immersive advantages [mvis.com] that RSD displays will bring to the mainstream in a few more years.

    I don't mean to knock the guys who work on CAVE... it's awesome considering current limitations...

    --

  • OK, so I go to UIUC and haven't heard of this. I'm only a freshman and not even in CS, so that seems probable. But get this - a road right next to my grandmother's house in good old, technologically backwards Inverness, Florida carries the exact same amazingly-lacking-in-common-vowels name on one of its roads. This is not even a normal road either. It's a road that goes for about five feet and then vanishes into a banal brown path. Now, I've got a fairly extensive vocabulary, but this word is utterly foreign to me. How could it possibly link the meager stretch of road in Inverness to an immersive virtual reality visualization system? Clearly a Google search was the first step in my investigation. I found that these are not the only products to carry this eclectic word as their name. We've got Syzygy.net [syzygy.net], a european firm specializing in the creation of e-businesses, a page documenting religious cults [virginia.edu], a hardcore eclectic videogame magazine [syzygy-magazine.com], and, my first solid lead, a company selling astronomical simulators [syz.com]. The last seemed to be the only lead worth following, and a dictionary.com search ended my confusion. Apparently, Syzygy is the key point in an ecclipse when the sun, moon, and earth lie in a straight line. For what it's worth, you can also have multiple Syzygies, but that word is not nearly as fun what with its normal vowels. My quest is now complete. Alas, now I'm at a loss as to what I can do to forstall finding employ over winter break. Ideas are welcome.
  • Have you ever heard of the visbox? Its a cave system that is pre built and pre configured, www.visbox.com [visbox.com]
  • Ok, you know about this system, and you know what goes into building a cave, right?:

    1. Several boxen
    2. This software
    3. Several projectors
    4. A tracking system
    5. 3D shutter glasses

    All of which can be expensive. If you aren't thinking. If you aren't hacking.

    Ok, you have the boxes and the software - that part is easy, and relatively cheap. But hey, six boxes can be expensive, especially when you are dropping good video cards into each. So what to do?

    Use three boxes instead. Each box should have a dual head card. Then build a three wall cave instead. Such a configuration can be done either as a front view and two sides, or "staring at a corner", that is, using two adjacent sides and the ceiling for the projection surfaces. The other two sides can be rigged with black velvet curtains to block light.

    Now, you need projectors. As we all know, such projectors aren't cheap - but they are coming down in price. If you can pick up six projectors (for stereo - two per wall) cheaply, more power to you. However, most of us won't be that lucky. So, what to do?

    Build your own projectors! [greenspun.com]

    This site was spun off, crazy as it sounds, from the 100 Inch TV list on the same server. The group is focusing on building video projectors using cheap and easy to get LCD TVs, etc. Robin Holland also wrote a VR Book that detailed such a projector (see my VR site for more details on that book) back in 1996 (as well as the 100 inch TV projector, but that was done by others before him and all this long ago, called the Warper for the AcidWarp program).

    Such projectors should prove not too difficult to build, and cheaply - but won't be high-res or anything - but they will be usable! I have a Fujix P-401 that is similar in design that is watchable, so I know what it would look like. If you build six of the projectors, you can use them with shutter glasses for stereo...

    So, you need shutter glasses! Where to get 'em cheaply? Try Ebay! Look at this link [ebay.com] for the systems currently on auction. There are a ton! But how to get 3D with your cheap LCD projectors (or even normal projectors)? Well, buy a pair of LCD 3D glasses for yourself, then a pair for every two projectors! Each pair will have two shutter LCD light valves - pull those out of the glasses, and place in front of each projector's output, and sync those with the glasses on the user. You may need to add fans to blow across these shutters to keep them from being overheated by the projector light source. Instant cheap 3D (but it may give you a headache after extended use)...!

    So, now you need tracking. This is the really tough part - but it is possible to build this yourself. If you look at my site, you will notice that in Issue 2 of Cheap VR, I tell how to build a 3D magnetic tracker. Well, I have news for you: I have found someone who has done it, independently of my article (that is, he didn't know about my site or articles):

    Juan's Homemade Magnetic Tracker [geocities.com]

    He has published a Circuit Cellar article on the tracker last August (2001) - detailing the construction and such. I was able to get a copy from him, and he says he plans on putting the article on his site for download. It looks like he is having traffic quota issues on part of the notes currently, but the PDF file will tell you a lot, and explains the math and theory behind it all (he covers a lot of things I didn't think of). Anyhow, notice in the pictures and movies that his hand is being moved inside a cube structure? That cube is the 3D tracker transmitter, similar in scope to what I wrote a long time ago. Anyhow - he has told me he is planning on building a 6 foot per side cube, to allow the tracker to track a user inside the cube. Check this: That cube structure can be your frame for the CAVE.

    Build a cube of sufficient size (6 foot per side or larger), add the coils, then add the projection screens (Want a cheap back projection screen? Use white-plastic painter's dropdown "cloths", or use clear plastic "cloths", then frost them with glass frosting paint. Finally, stretch the plastic on the frames). Put the edges right against each other, so that the "seams" between the screens are minimized. Use the homebrew projectors to project against them (for the dual projection system, place the projectors as close as possible together - there will be some keystoning, but hopefully not too much to cause major issues).

    There you have - a quick and easy CAVE system. Now, mind you, this won't be a simple construction project - not at all. Main reason is size, because you will need a room larger than the "inside" room you are building for the CAVE. But I can see this being done in a spare bedroom, or maybe a garage, given enough ingenuity.

    So, now that you have an idea - someone try it out (hell, I would if I had the room) - and email me and let me know how it works...
  • Though it's our sister school, we're always in the shadow of UI Urbana-Champaign (and the bastards always kick our ass in basketball), so I feel the need to say the CAVE was originally developed at UIC, University of Illinois-Chicago. I still remember being a freshman engineer and being shown around. It's on all the tours, kind of a "go to school here and you get to play with cool stuff like this".

    The CAVE was developed by Dr. Tom DeFanti in the EVL [uic.edu] (web site currently sucky). DeFanti has been in graphics for a long time, even doing all the CG for the original Star Wars. You can find some interesting stuff at Dave's CAVE pages [uic.edu].

  • Check it. I wrote the specs on a new type of video gesture interface using a person's body position as input.... Add in some holograms(if possible) and you have the next gen video fighting games, or control for robotic warriors in a field of war

    www.contrib.andrew.cmu.edu/~sager
  • There isn't anything new involved here. All you need is the projectors... LOL. It isn't even a difficult computing problem. Nor a difficult problem to 'lock' multiple CPU's rendering multiple windows (all a CAVE actually is.) U of I hasn't done anything that hasn't been possible since 1996 (even earlier technologically.)
  • This is not really new. At the Fraunhofer institute of Industrial Engineering (IAO) in Germany they already have 6-sided cave running, that uses PC based passive stereo or SGI Onyx based active stereo. A description can be found here [iao.fhg.de].

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