mwtilden@watmath.waterloo.edu (M.W.Tilden, Hardware) (06/07/90)
My second mail reply about the Cyberdesk design to erich. ---- > Anyway, onto more comments... > > Now, as to not wanting to use the VR systems (since they are not >"dignified"), > > (1) Wouldn't it also be easy to just ask people to stay sitting down > most of the time? (since this would leave versatility to spare) Sorry. Come again? Of course you want people sitting down. Programmers and users expect a comfortable, simple environment. > (2) In the case of the variable-transparency "video-dome", wouldn't it > be just as easy to use high-resolutin LCD with a background that > would be capable of going just as tranparent? (they could almost be > mounted in a pair of glasses, a bit thicker of course, with other > equipment mounted on them. Altogether, it would be like a pair of > wraparound sunglasses (a bit heavy, I agree)) The stamping process to make even small (4") high-res flat LCD screens is pushing the limits of modern technology. Making a curved form for glasses (or the inside of a CHUV) is not even being considered so far as I've read (the trend is instead towards flat-flat Monitors). Even given every consideration, the lightest form of VR glasses would still have to mount it's projectors around the ears just to get an effective weight/distance corrolation (by bouncing the images off a front visor). You stick LCDs 2 inches in front of you and all you see is a blur, and the appropriate lenses are just prohibitably heavy (although not unusable. Tryed one at Siggraph last year). Making the CHUV out of such components would be difficult because you would still require diffuse back lighting to make it viable. This might be possible by using a circular ribbon florecent tube but it could would not be transparent, and I think that's a semi-essential feature. Actually, now that I think of it, it might be possible if you could fill the CHUV exterior walls with a semi-luminecent gas which was both variably transparent and luminecient at set voltages. I'm not sure if such a gas or fluid even exists though. Polarizing lenses which turn variable black/white do, however, and would be far more robust and simpler to implement than the above. For maximum efficiency, the CHUV should have an internal white polarizing filter (to act as an effective reflection screen for the LCD projectors) and an external black polarizing filter which would selectively shut out external light sources. Most people would feel a slight anxiety about sticking their head in a huge light-bulb anyway. > (3) Now, the issue of moving through the "virtual-world" is presented, > and that would be addressed well with the CHUV, since that would be > much like flying a "virtual-aircraft", with very convenient and > responsive controls. This would be the hardest to address with a > VR-like system. You mentioned the incident that led you to keep away > from VR-type systems. Staying seated would solve this problem, but > it would make it hard to "get around" in the virtual world. I must > admit, the databall is an excellent solution to this type of problem. Best I could think of too. It also provides for mobility not normally associated with real life. To wit: scaling (make a "model" house, then scale yourself small enough to walk through it), select gripper scale, gripper type, pause control, rewind/slow/play options, sound control. So long as you get familiar with the fact that every finger has three buttons in easy reach, eventually you won't even look at the buttons you're pressing. You'll just do it. > (4) Lastly, has the problem of efficient force-feedback with low drag > on the arm been dealt with much? Your design appears good as basic > force-feedback, but there is the question to consider that if it > offers too much drag on the arm that it could be too inconvenient to > use. This is where VR fails totally, I know, but the overall > interface elegence of VR catches at me, as mentioned in the previous > letter. Besides, it would be more portable, as I think that in a > couple of years that it could be reduced almost to the "wraparound > sunglasses", the dataglove(s), and the main box (with a serial > port for the console, of course). Just you try typing with gloves on and you'll soon see why I promote this design. It'll be years before a fully VR symbolic programming language will be available (APL does make a good stab at it, I'll warrent). People use keyboards now and will for some time. We cannot ignore their dominance, much as we'd like. Voice actuated commands are good for dictation, but it'll be a while before they offer the abilities of edit-arrow keys. Anyways, that's SEP (Someone Elses Problem) and only time will tell. My original sketches for the Follow/Restraint Arm (FRA) basically thought of it as being not much more heavier than a Luxo-lamp. The original experiment I did was to loosen up the joints in a Luxo, ply them with WD40 and adjust the springs so that they could barely raise it at full extension. The results were promising (although I can never use that lamp again. It keeps on moving by itself) but inconclusive. Although I made several attempts at motion limiting, I was working one handed and was distracted before I'd analysed it thoroughly. My conclusion was to use light-weight brass tubing connected by Universal joints at two axes. Such tubing has a superior ridgidity/stress ratio and also allows effective paths for connection wires. You can solder to it and, most importantly, you can buy it cheaply from most Model/Hobby shops. As for the restraint motors, I've just received a set of DC motors not much larger than a pen cap. As my original restraint design uses only DC motors (for optimal simplicity and cost efficiency), I am now fairly certain that I could build an effective FRA of extreme lightness and fair cost. Don't forget that my design never requires the motors to actually move the FRA, only to move stop-gaps which can be very light indeed. Time will tell. > In case you're curious (and don't know already), there is a VR lab in >Seattle, Wasington that is offiliated with the University of Washington called >HITL (Human Interface Technology Laboratory). They did post on >'sci.virtual-worlds' that they planned to standardize the VR paradigm, and >there may be a job for me with them over the summer (I find out in a couple >of days). I think that they are working on trying to get the cost into >a "reasonable" range, whatever that would be for this kind of equipment, >and I think that the LCD displays was one of the methods for making the >helmet more reasonable to wear. The moderator of this newsgroup is in fact associated with that very lab. He should have gotten a copy of the cyberdesk docs several weeks ago. No doubt he is listening even as we speak... Helmet designs have some inherant problems, not the least of which is that you could never feel right about using one in an office (unless there's a real nation-wide psycological-profile shift sometime soon). The main thing is that anything that employs moving parts to a human body will be subject to fatigue and wear, more so than you think. Just think of the relative lifetime of your standard watch. That it survives the amount of time it does is a miracle considering the abuse it's put through. Helmet VRs will be subject to infinitely more damaging stresses because of their size and complexity, and furthermore they will have to be *tethered*. I can't even wear a pair of headphones without continually ripping out the jack by involintary movements. Imagine the problems of being tethered to a box/chair/desk by a hefty optical bundle. Someone slaps you on the back. You stand up to punch his lights out. Your tether holds as you rise, snaps your neck, game over. Well, not really, but it would be inconvenient to re-plug a high-accuracy fiber bundle everytime you wanted to stand up. It's weight and constraints would be a constant distraction. The CHUV avoids all of these problems. As soon as it's out of the way, you're out of there. Even if it's not powered it wouldn't be any more trouble than a car door. Furthermore, it can be made just as robust. > All-in-all, though, I think that you may be right that yours is a more >practical interface, and could very well be a standards-setter. What kind >of support would you need to work on something like this? (you mentioned that >you have resources available as it is, how much more would we be talking >about here?) The last page of the Cyberdesk sketches is a cost breakdown if my University were to commission me for the job (fat chanceski [sic]). In the month since I drafted the Cyberdesk, design rethink has only changed that marginally. The practical upshot is that to build the desk, the individual components would have to be tackled individually (by six design groups possibly) who would ultimately collaborate on the final product. People would come and go. Ultimately you would have a hardcore group of cyber-junkies who could finish the prototype. That done, we release it on the graphics-programming kids and let them have a field day. Based on response, we then build another, improving on the older design while keeping it compatible for full portability. Repeat until software tools are sufficient, then call in the Corps/Govt for a 'demo' and nail them for funding. Hire a Lawyer. File patents. Publish papers. Start a company. Rise to the top in meteroric success. Sell out. Buy an island and live there the rest of your days surrounded by beautiful Tahitian maidens. Gotta have priorities, after all. On the other hand, it *might* be cracked out in two years of dedicated slogging by one hyper-active engineer, 10,000 gallons of coffee, $8,000 of Domino's pizza, and the surplus junk kicked out by an average-sized technical College or University (tools extra). That, for the most part, is what I based my original estimation on. That's what I'm sitting in now. I'm kidding, of course. You don't know how it frustrates me that this could in no way be considered a one man project. It needs a team of fanatical, experienced, multi-diciplinal egos all with one goal in mind. The only people I think that would qualify work at Industrial Light and Magic. Does Lucas read news? The main expenses would be, in order: multiple graphics CPU (four IRIS/SPARC/APOLLOs or one SUN/IBM with 4 video-cards? Good question), multiple high-res LCD projectors (which, I see, Sharp has just come out with. That'll save a bit of work), specialized carpentry for the CHUV chair, ditto the desk, sundry VCR equipment (did I mention the Multimedia options this thing could have?), CHUV LCD projection screen (I can see it now: "You want a pair of Polaroid glasses *how big*!?"), databall (with appropriate carpentry), 3-D glasses, color monitor, x-window terminal and the rest is prototype obscurity. There you go. Mix well, bake for 2 years in a Cyber-sweatshop, serve with recreational pharmacuiticals to avid computer-graphics hacks. Is all. ---- Posted with permission. Is really all. -- Mark Tilden: _-_-_-__--__--_ /(glitch!) M.F.C.F Hardware Design Lab. -_-___ | \ /\/ U of Waterloo. Ont. Can, N2L-3G1 |__-_-_-| \/ (519) - 885 - 1211 ext.2454, "MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"