Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!milton!hlab From: brucec%phoebus.labs.tek.com@RELAY.CS.NET (Bruce Cohen) Newsgroups: sci.virtual-worlds Subject: Re: Update rate, and the C-words Message-ID: <1991Apr8.000801.8080@milton.u.washington.edu> Date: 7 Apr 91 20:11:42 GMT Article-I.D.: milton.1991Apr8.000801.8080 References: <1991Apr3.060218.4122@milton.u.washington.edu> Sender: hlab@milton.u.washington.edu (Human Int. Technology Lab) Organization: Tektronix Inc. Lines: 59 Approved: cyberoid@milton.u.washington.edu In article <1991Apr3.060218.4122@milton.u.washington.edu> cdshaw@cs.UAlberta.CA (Chris Shaw) writes: > > In article Alan Kilian writes: > >>Basically everything "science" is all floatingpoint. >>So, the moral of the story is that we need gigaflops. > > Agreed. Of course, maybe we don't need a lot of scientific simulation in > our virtual worlds. To date, I've seen only three groups that do simulation in > their worlds. There's lots of people making viewers of static polygonal models . Sure, but in the long (and maybe the not-so-long) run, we need to simulate physical objects for VRnauts to interact with. (And before anyone jumps on me for being a reality chauvinist, I'll point out that the object may respond to a physics different from the one we see when we're not wearing the goggles). The state of the art in physical simulation of mechanical systems (bridges, chains, snakes, and jello) involves solving a set of simultaneous differential equations everytime a part moves or the forces on it change. In my book that means floating point, and lots of it. Well, you say, why do I care about simulating physical objects? After all, isn't a door just a bunch of polygons? No, I answer, not if you want to be able to knock on it, or push it open with a stick rather than touch it with your finger (veterans of dungeon adventuring will recognize these strategies), and have it react like a door with mass and squeaky hinges ;-). But leaving aside the entertainment applications, consider the example that Moravec gives in "Mind Children": learning physics interactively by going inside a VR where you can play with objects while modifying the objects and the constants of nature. Now, you could argue that that's scientific visualization too, and you'd be right (though it better be a lot cheaper than the systems used in research if many people are ever going to learn that way). So let's consider VR applied to a business use: working with a large database of business records. I think it would be very nice to design a file object, whatever it looks like, so that it's perceived mass would depend on the amount of information in it. You could heft a file and decide very quickly whether you wanted to get involved with it just now or go for coffee. Ok, it's a little fanciful. But that's eactly why VR will be useful in the long run: to open up the metaphors we use when interacting with information systems to a little fancy, so we can find more efficient (in terms of the user) and more interesting (to make the user more engaged in the work) ways of interacting. So in my opinion, physical simulation will be a very big part of the inplementation of most commercial VR systems (after the initial "glitz" phase, assuming it survives that), and floating point arithmetic will be part of that. -- ------------------------------------------------------------------------ Speaker-to-managers, aka Bruce Cohen, Computer Research Lab email: brucec@rl.labs.tek.com Tektronix Laboratories, Tektronix, Inc. phone: (503)627-5241 M/S 50-662, P.O. Box 500, Beaverton, OR 97077