cyberoid@milton.u.washington.edu (Robert Jacobson) (10/01/90)
Date: 27 Sep 90 17:45:22 GMT References: <31304@unix.cis.pitt.edu> <7507@milton.u.washington.edu> <7801@milto < 8204@milton.u.washington.edu> Organization: Tektronix Inc. In-Reply-To: mike@x.co.uk's message of 26 Sep 90 13:55:30 GMT In article <8204@milton.u.washington.edu> mike@x.co.uk (Mike Moore) writes: > What I'm saying is that > in a VR environment if we don't want people entering a room, we don't > even tell them it's there, they just see a blank wall (or one with > pictures hung on it, or whatever) and all the hacking in the world won't > change that fact. For people we do want to allow in there is simply an > entry point, no messing around with doors just a 'transporter' machine/ > object which moves you into the chosen room/building/area/'country', > wherever you intend going. I think this is a very limited and limiting view of the way the designer and inhabitants of a virtual reality interact. The implication is that a world is finished and perfect construct, whose designer has considered every interaction possible, and knows the nature of every use to which the world will be put (or even most of them). This is not the way complex systems are introduced in the "real world". Often, particularly in systems with complex user interfaces, new interactions and new applications for the system come to light for years after the designer has gone on to other projects. I view a virtual reality as very much like an interactive fiction: a collaboration between the designer and the inhabitants. The designer puts in the basic set of objects and relationships and the inhabitants use them and build on them to make the reality suitable for their own purposes, which may or may not have been forseen by the designer. Over time, a well-designed VR would evolve as the inhabitants modified and enhanced it. In this context, the criteria for a good VR design are not completeness and fit to initial specification, as is common in systems development today, but internal consistency and extensibility. Wasn't it Stewart Brand who said, "We are become as gods, and damn well ought to learn how to be good at it"? VR makes the designer a god, and ought also to confer some divinity on the inhabitants. How else do you apprentice as a designer? > Something else I'd like to start a discussion on is the apparent necessity > we have of modelling the real world. I believe that so long as the physical > laws are apparent, there is no need to extend beyond this (of course, we > don't *really* want to accurately model somebody jumping off the golden > gate bridge!). Familiar objects are already changing in the real world, > push-button phones as opposed to rotary phones, digital display watches > as opposed to analogue display. The virtual reality would begin to alter > these 'familiar' objects in the same way that digital electronics has > already altered the real world examples I've given. I'm currently thinking > about what might be the most spectacular changes, but the 'door' argument > above is a good enough example to begin with. The key phrase here is "would begin to alter", implying gradual change. As I said above, I expect any good VR to evolve; I suspect our ideas of what to expect in a VR designed for a given application area will also evolve. Likewise, the class of kinds of model represented in our VR's will expand over time, slowly at first, perhaps, but it will happen. The change is likely to be incremental, as VR designers take a baseline "real-world" VR and modify a few attributes to make it more exotic, perhaps just removing gravity, or making light work by flowing out from the eyes to the things we want to look at. There are several reasons for starting with something as much like the real world as is practical for the level of computer power and the complexity of the I/O devices we have available: 1) The real world is the only example we have of a physically-based world all of whose perceptible attributes are related in a way which makes that world self-consistent, i.e., it's already been debugged. 2) We know how humans react to real-world stimuli to a large extent, which means we can measure how well our models match what humans expect, i.e., we have a baseline to work from. 3) There has been a *VERY* large amount of work done in simulating real-world processes and displaying real-world-like objects on computers. This gives us a head-start in building our prototype systems. AS an engineer, it's always been my policy to build on other people's work as much as possible: I represent perhaps 30 person-years of potential effort at best and there are person-millennia worth of research and development out there waiting to be used. 4) Moving from the real world to a similar VR doesn't require a large cognitive leap, or much training, on the part of the user. In the early stages of research this makes it easier for users to evaluate the quality and nature of the VR they inhabit. As a user gets more experienced, she'll be better equipped to go on to more exotic worlds. Right now, we don't have any experienced users. 5) VR designers need some experience too. Working incrementally from a robust, well-constructed, "real-world" model is a good way to get that experience. 6) I suspect we'll learn more about what we can do to modify VR models from letting the VR inhabitants mess around with the rules than any other way. That means starting with a baseline, and giving users the tools to modify it incrementally. Along the way, we have to learn how to reconcile conflicting world-views as well. -- --------------------------------------------------------------------------- NOTE: USE THIS ADDRESS TO REPLY, REPLY-TO IN HEADER MAY BE BROKEN! Bruce Cohen, Computer Research Lab email: brucec@tekcrl.labs.tek.com Tektronix Laboratories, Tektronix, Inc. phone: (503)627-5241 M/S 50-662, P.O. Box 500, Beaverton, OR 97077
cyberoid@milton.u.washington.edu (Robert Jacobson) (10/01/90)
Responses to the last article should be sent to Bruce Cohen at bruce@tekcrl.labs.tek.com Please do not send them to me, as may happen if you use the automatic reply. My name was interposed with Bruce's in the header. (Lesson #367!) Bob Jacobson
mike@x.co.uk (Mike Moore) (10/03/90)
>Mike Moore (i.e. me) writes: >> What I'm saying is that >> in a VR environment if we don't want people entering a room, we don't >> even tell them it's there, they just see a blank wall (or one with >> pictures hung on it, or whatever) and all the hacking in the world won't >> change that fact. For people we do want to allow in there is simply an >> entry point, no messing around with doors just a 'transporter' machine/ >> object which moves you into the chosen room/building/area/'country', >> wherever you intend going. Buckaroo Banzai [wex@dali.pws.bull.com] (Hi Alan!) writes: >Well... yes and no. I'm extremely fond of the "new modes of interaction" >idea. Driving while looking in the rear-view mirror will only get us so >far. But on the other hand, it's extremely hard to ignore, as Meredith >Bricken put it, the fact that we're wired for up/down, forward/backward >one-step-at-a-time. It's some of the most deeply learned behaviors and >relationships we have to the world. I agree with you entirely. Any three dimensional virtual world will certainly have to cope with this concept in some form. Bruce Cohen [brucec@tekcrl.labs.tek.com] writes: >I think this is a very limited and limiting view of the way the designer >and inhabitants of a virtual reality interact. The implication is that a >world is finished and perfect construct, whose designer has considered >every interaction possible, and knows the nature of every use to which the >world will be put (or even most of them). This is not the way complex >systems are introduced in the "real world". Often, particularly in >systems with complex user interfaces, new interactions and new applications >for the system come to light for years after the designer has gone on to >other projects. I'm sorry if I gave this impression, that was not what I meant, and I agree with you that any system as complex as a world-wide network of VR machines would be impossible to analyse completely. I was looking more from the point of view that when a new 'room' comes on-line, it is the responsibility of the designer to ensure that only the people he wants in are allowed in (see further below). Bruce Cohen [brucec@tekcrl.labs.tek.com] writes: >I view a virtual reality as very much like an interactive fiction: a >collaboration between the designer and the inhabitants. The designer puts >in the basic set of objects and relationships and the inhabitants use them >and build on them to make the reality suitable for their own purposes, >which may or may not have been forseen by the designer. Over time, a >well-designed VR would evolve as the inhabitants modified and enhanced >it. In this context, the criteria for a good VR design are not completeness >and fit to initial specification, as is common in systems development >today, but internal consistency and extensibility. > >Wasn't it Stewart Brand who said, "We are become as gods, and damn well >ought to learn how to be good at it"? VR makes the designer a god, and >ought also to confer some divinity on the inhabitants. How else do you >apprentice as a designer? Yes! I like this idea. But it wouldn't be the only kind of environment available. But take another example I came across the other day (from a famous book I borrowed of a friend over a drink for 10 minutes, so I'm not accurate [from Mind Children by Hans Moravek]) that is basically a school, or a VR, AI text book. It gives you individual tuition (on a time-sharing basis) and even allows you to interact with other students so you can choose to learn together or on your own. Not in a school, but walking along an orchard path with Isaac Newton to learn about gravity and mass, or in a train to learn about the Doppler effect, and relativity with Einstein (or, at least, VR AI interpretations of them). Now you *don't* want people messing around, they have a limited set of allowable actions. They won't bring anything with them, and they probably won't take objects away. Each VR environment will have it's own set of constraints on what can and cannot be done, and collaboration is merely one example of one set of 'constraints'. Buckaroo Banzai [wex@dali.pws.bull.com] writes: >That's why I agree with the assertion >that you can't train a cybernaut, you're going to have to breed one. I understand what you are saying here, but, are good fighter pilots/submarine captains trained or bred? It is not within our instinctive make-up to understand the complex relationships of manouevering within 3d space (as many a fighter pilot might tell you) and these skills are most definitely learned. Why should manipulation of cyber-space be anymore complex (I should hope it will be infinitely easier!) Buckaroo Banzai [wex@dali.pws.bull.com] writes: >One need only see the differences in adults & children using a powerglove in >order to see the truth of this. You and I are already too old, our brains >too ossified. It's not!! :-) (At least mine isn't! :-) You and I are into the computer 'world' and it's not just my grandmother or my parents who don't understand it (to my genuine surprise when I first discovered). Many people of my/your own age group are not only confused by what's going on, they just don't have any interest outside of what they *have* to know to operate within their work environment. Granted that being exposed to technology at an early age is (like reading) a major reason why those kids grow up knowing how to use, and how to appreciate, technology; I would still argue that it is not a prerequisite. Buckaroo Banzai [wex@dali.pws.bull.com] writes: >We're trained that if we want to enter a room, we look for a >more or less conventional entry point (door, window, chimney). Those of us >with slightly bent minds can accept a teleporter to get us inside. But the >"transporter machine" is still a door in terms of its affordances. Agreed. I didn't mean that the concept 'DOOR' would disappear, more that the application of the concept would change (like the application changed with automatic doors). In fact, the application of the concept could (and should) be a user defined parameter, unless specific situations call for this to be over-ridden. To explain my point in this context, if I were denied access to a room by some security software, it would be in the best interests of the software to not even inform me of the existence of the room. i.e. on entering an area I must identify myself and then the software informs me of what it wants me to know. (see below) >Mike Moore (i.e. me) writes: >> In my (humble) opinion, there isn't a need for every object to shout it's >> attributes at me when I enter a room. An object is a passive item that is >> acted on, and, if I perform an action recognised by the object it performs >> an action of it's own. Buckaroo Banzai [wex@dali.pws.bull.com] writes: >But this begs the question. If the objects in the room don't shout at you, >how do you know they're there? Uhhh.... yes... well... I didn't explain that very well did I? This was to apply to all attributes *except* visual attributes. i.e. all objects that I am meant to see, I receive a visual description, and all objects I am not meant to see, I don't. Buckaroo Banzai [wex@dali.pws.bull.com] writes: >How do you know what you can do with >them? How do I know how to breath? How do I know how to talk? How do I know what to do with a book? It is either intuitive knowledge, experiential (is there any such word?) knowledge, or received knowledge. i.e. I know because I know, I know because I've experimented around a bit, or I know because I was taught. >Mike Moore (i.e. me) writes: >> Something else I'd like to start a discussion on is the apparent necessity >> we have of modelling the real world. I believe that so long as the physical >> laws are apparent, there is no need to extend beyond this (of course, we >> don't *really* want to accurately model somebody jumping off the golden >> gate bridge!). Familiar objects are already changing in the real world, >> push-button phones as opposed to rotary phones, digital display watches >> as opposed to analogue display. The virtual reality would begin to alter >> these 'familiar' objects in the same way that digital electronics has >> already altered the real world examples I've given. I'm currently thinking >> about what might be the most spectacular changes, but the 'door' argument >> above is a good enough example to begin with. Buckaroo Banzai [wex@dali.pws.bull.com] writes: >See above for a partial answer to this. I'll also recommend again my two >favorite papers on this topic: > > Smith, Randall B. "Experiences with the Alternate Reality Kit: An > Example of the Tension Between Literalism and Magic," CHI+GI'87 > Conference Proceedings, April 1987. > >and > > Fairchild & Gullichsen. "From Modern Alchemy to a New Renaissance," > MCC Technical Report HI-400-86, December, 1986. At the risk of appearing to be really thick (which, imho, I'm not, honest :-) do you have any idea where I might be able to locate these in the UK? >"Politics is Comedy plus Pretense." "Politics is what happens when you have more than one person." Bruce Cohen [brucec@tekcrl.labs.tek.com] writes: >The key phrase here is "would begin to alter", implying gradual change. As >I said above, I expect any good VR to evolve; I suspect our ideas of what >to expect in a VR designed for a given application area will also evolve. >Likewise, the class of kinds of model represented in our VR's will expand >over time, slowly at first, perhaps, but it will happen. The change is >likely to be incremental, as VR designers take a baseline "real-world" VR >and modify a few attributes to make it more exotic, perhaps just removing >gravity, or making light work by flowing out from the eyes to the things we >want to look at. > >There are several reasons for starting with something as much like the real >world as is practical for the level of computer power and the complexity of >the I/O devices we have available: > > 1) The real world is the only example we have of a physically-based > world all of whose perceptible attributes are related in a way which > makes that world self-consistent, i.e., it's already been debugged. Eeek! Really? Last I heard (oh, my memory!) some mathematician at MIT had proved the universe started from nothing (really!). It went something like, if nothing exists for an infinite time, an infinite number of events will take place, one of those possible events is the spontaneous creation of matter. He then went on to do a lot of very difficult (to me!) math to prove it. This says to me that the whole universe is just one monumental bug! :-) :-) :-) (but the MIT mathematician bit is the truth!) For a (slightly) more serious reply. 1) The universe (as we know it) is consistent only on a macro level. Half of the study in nuclear physics is currently revolving around Quanta (i.e. the *probability* that if cause A occurs effect B will seen rather than effect C). 2) To model the real-world we would need to model the non-perceptible parts of the world as well. i.e. Solar radiation (non-perceptible, at least without instruments) acts on the upper atmosphere (non-perceptible, unless you happen to be there) and the Magnetosphere (non-perceptible) to produce the Aurora Borealis, which *is* perceptible. This is a lot of modelling. And for what? Do we even *want* an Aurora Borealis in our VR environment? Like, do we want to allow the odd idiot to jump of the Golden Gate Bridge? > 2) We know how humans react to real-world stimuli to a large extent, > which means we can measure how well our models match what humans > expect, i.e., we have a baseline to work from. In so far as it is a proof for a model of reality that you have built, yes I agree. But, as above, is this what we want? > 3) There has been a *VERY* large amount of work done in simulating > real-world processes and displaying real-world-like objects on > computers. This gives us a head-start in building our prototype > systems. AS an engineer, it's always been my policy to build on > other people's work as much as possible: I represent perhaps 30 > person-years of potential effort at best and there are > person-millennia worth of research and development out there waiting > to be used. Again, I agree. But as an engineer, you would realise that modelling the effects of radiation from plutonium on tin is completely irrelevant to modelling the effects of wind on a building. These 'real-life' simulations are *very* specific, and don't even pretend to tackle the problems involved in interaction. Therefore, as I might be explaining a bit better by now, we do agree; but I envisage people moving from environment to environment, each with it's own constraints (it's own laws of gravity, motion, dimensionality, etc...). > 4) Moving from the real world to a similar VR doesn't require a large > cognitive leap, or much training, on the part of the user. In the > early stages of research this makes it easier for users to evaluate > the quality and nature of the VR they inhabit. As a user gets more > experienced, she'll be better equipped to go on to more exotic > worlds. Right now, we don't have any experienced users. True, but when computers hit the market for the first time, there were very few experienced users. When cars hit the market for the first time, no one could drive. People *do* learn (when motivated). > 5) VR designers need some experience too. Working incrementally from a > robust, well-constructed, "real-world" model is a good way to get > that experience. Hmmm.... I see what's happening. You are working on the assumption that VR will *start* with a realistic 'real-world' reality (hey! that's good!) whereas I see us starting with nothing (or very close to nothing) and working up to a realistic 'real-world' reality. I must admit, I think that my view is more realistic :-) <groan> But please explain more of what you are thinking, I feel as though there's a huge chasm I've missed somewhere. Why do you believe we'll start at realism and work down? > 6) I suspect we'll learn more about what we can do to modify VR models > from letting the VR inhabitants mess around with the rules than any > other way. That means starting with a baseline, and giving users > the tools to modify it incrementally. Along the way, we have to > learn how to reconcile conflicting world-views as well. Now this I don't understand. From your point of view, if it is a good model of reality, how is it possible to have conflicting world-views (other than psychologically). From my point of view, every gets there own individual world view, just the same as you get your own individual copy of this article. Please elaborate. -- --- Mike Moore mike@x.co.uk or mike@ixi-limited.co.uk Usual and obvious disclaimers... etc
wex@pws.bull.com (Buckaroo Banzai) (10/06/90)
In article <8514@milton.u.washington.edu> mike@x.co.uk (Mike Moore) writes: >Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>That's why I agree with the assertion >>that you can't train a cybernaut, you're going to have to breed one. > >I understand what you are saying here, but, are good fighter pilots/submarine >captains trained or bred? It is not within our instinctive make-up to >understand the complex relationships of manouevering within 3d space (as >many a fighter pilot might tell you) and these skills are most definitely >learned. Why should manipulation of cyber-space be anymore complex (I >should hope it will be infinitely easier!) I don't know enough about submarine captians, but my reading indicates that good fighter pilots really are "born." Most people have the 3D sense to learn to be a pilot, but the acrobatic free-form nature of aerial dogfight is another story entirely. To a large degree, it seems to be true that the "experts" in a field (like the international grand masters in chess) are born in some way different from the rest of the population. What they do goes beyond simple learning (or even advanced learning). All the studies of expertise that I've seen indicate that the experts somehow conceptualize the world in a different way (e.g. Hawking talks about 'seeing' mathematics). This may also explain why people who are so good at one thing tend to be bad at other everyday things (like social interaction). This doesn't have to be all negative. VR can allow us to build worlds with totally different reality modes for different types of users. The average joe/jane might want something that pretty closely models the regular universe. I personally would like a universe where things behave normally except I can get at the controls and change them as I desire (e.g. by turning off gravity or by enabling myself to teleport with a thought). Interacting with cyberspace will, I fear, always be harder and more complex than reality. No computer desktop (to take another example) will ever be as simple as my physical desktop. Wang's Freestyle came as close as I think a computer can, and it still wasn't as simple. >people of my/your own age group are not only confused by what's going >on, they just don't have any interest outside of what they *have* to >know to operate within their work environment. Granted that being >exposed to technology at an early age is (like reading) a major reason >why those kids grow up knowing how to use, and how to appreciate, >technology; I would still argue that it is not a prerequisite. No, of course it's not an absolute prerequisite. There are kids who go into kindergarten knowing how to read, having picked it up from obser- vation and mimcry at home. The exception doesn't disprove the rule. It's just that the rule covers 98% of the cases. As for the disinterested majority (aka sheep), I've long ago given up designing systems for them. I'm very bad at pleading, coaxing, and cajoling. I will not ignore their legitmate concerns and desires (I'd be a pretty crappy human-interface designer if I did that), but I've learned that the old saw about a horse and water is still true. When the sheep get thirsty, they'll drink and nothing I do between now and then is going to get them to drink any sooner. >Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>But this begs the question. If the objects in the room don't shout at you, >>how do you know they're there? > >Uhhh.... yes... well... I didn't explain that very well did I? This >was to apply to all attributes *except* visual attributes. i.e. all >objects that I am meant to see, I receive a visual description, and >all objects I am not meant to see, I don't. Right. Remember, though, that we were discussing a general object-interaction protocol. What you get from an approaching baseball is probably different from what a bat gets (or a glass window, for that matter). But to know that requires a *lot* of knowledge about the "real world." I seem to have failed to express this simple point very well since almost everyone misunderstood me. >Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>How do you know what you can do with them? > >How do I know how to breath? How do I know how to talk? How do I know >what to do with a book? It is either intuitive knowledge, experiential >(is there any such word?) knowledge, or received knowledge. i.e. I know >because I know, I know because I've experimented around a bit, or I know >because I was taught. In other words, the properties of the object were communicated to you in some way (which was my major point). On a side note, you are also (perhaps unintentionally) highlighting how important it is to have a VR where we can carry over a lot of our real-world learning. I don't fancy having to re-learn how to walk. But that's what's going to happen to a lot of people in a lot of the VRs people are talking about building. >Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>See above for a partial answer to this. I'll also recommend again my two >>favorite papers on this topic: >> >> Smith, Randall B. "Experiences with the Alternate Reality Kit: An >> Example of the Tension Between Literalism and Magic," CHI+GI'87 >> Conference Proceedings, April 1987. >> >>and >> >> Fairchild & Gullichsen. "From Modern Alchemy to a New Renaissance," >> MCC Technical Report HI-400-86, December, 1986. > >At the risk of appearing to be really thick (which, imho, I'm not, honest :-) >do you have any idea where I might be able to locate these in the UK? The MCC paper you can get by writing to the MCC librarian (3500 Technology Dr Austin, TX 78759, USA. Enclose SASE). Check your local technical/university library for the CHI/GI proceedings, or write to ACM. -- --Alan Wexelblat phone: (508)294-7485 Bull Worldwide Information Systems internet: wex@pws.bull.com "Politics is Comedy plus Pretense."
brucec%phoebus.labs.tek.com@RELAY.CS.NET (Bruce Cohen;;50-662;LP=A;) (10/10/90)
I'm falling behind a few days here; they want me to do some of the work
they pay me for here! Of all the cheek!
I think I'll handle these points out of order, since the one I want to
handle first is the most fundamental:
I think I see basic point of disagreement between Mike Moore and me , and I
think it's based on a misunderstanding. When I say "modelling the real
world", I mean that in the sense of a mathematical model, in which the most
important aspects of the world (important to the particular model, of
course) are abstracted and used in the simulation, and the rest ignored. I
think Mike took me to mean a complete model in which all (or as many as we
have computing power for) aspects of the world are simulated. And when he
disagreed, I thought he was talking about *different* models, rather than
less complex models.
Consider computer graphics as an example: most realistic shading algorithms
are based on physical models, but they all involve certain simplifying
assumptions which make them physically incorrect, but computationally
tractable. For instance, Gouraud shading gets good performance by ignoring
specular reflection, and thus not being able to simulate highlights on
shiny surfaces. Phong shading puts in the highlights at a cost of roughly
an order of magnitude over Gouraud, but makes some simplifying assumptions
about the smoothness of the reflecting surface. Neither of them is a
perfect model of the real world, but they are points in a spectrum of
techniques which range from highly abstract to highly realistic. But all
of these techniques are based on the laws of physics as we know them, they
just simplify them.
There's another alternative in designing a model: choose one which
simulates a world which contradicts the known laws of physics, chemistry,
etc. Sort of like playing fairy chess: the pieces and the moves may be
wildly different from the standard game; the challenge is to make the game
internally consistent, that is, playable.
Obviously, in this context "realism" is a relative, and almost useless word
(come to think of it, that may be generally true; it's certainly true in
the theatre and movies as well). I'm using it in the sense of the
mathematical model I spoke of above. So to me, "non-realism" means, not
something which is less than real, but something which is contrafactual. I
would love to spend time exploring the design and use of contrafactual
physical worlds, but I'm arguing against spending much time doing that at
this stage in the development of VR.
So I advocate starting with as good a simulation of the real world
("consensus reality" if you like) because we know it's consistent, and
highly playable. Besides that, there are a lot of existing simulation and
display techniques available to the VR programmer, often as publically
available code, which are based on the laws of physics. Making them fit
some arbitrary set of non-realistic laws is probably more difficult.
Now, I think that Mike is saying that we should start with as small a set
of "physical" laws as possible, and work up. So let me respond to the
question:
In article <8514@milton.u.washington.edu> mike@x.co.uk (Mike Moore) writes:
<first I said>:
>> 5) VR designers need some experience too. Working incrementally from a
>> robust, well-constructed, "real-world" model is a good way to get
>> that experience.
>
> Hmmm.... I see what's happening. You are working on the assumption that
> VR will *start* with a realistic 'real-world' reality (hey! that's good!)
> whereas I see us starting with nothing (or very close to nothing) and
> working up to a realistic 'real-world' reality. I must admit, I think
> that my view is more realistic :-) <groan> But please explain more of
> what you are thinking, I feel as though there's a huge chasm I've
> missed somewhere. Why do you believe we'll start at realism and work
> down?
>
As I said, there's a lot of art out there already. And ask yourself what's
the mininum reality which a human user will accept as having some physical
existence, that is, will give the sense of "presence" which we would like
to provide. Do you need inertia for objects? Should they have flat color,
highlights, shadows? Are there doors and do their hinges squeak? :-).
Seriously, I think we need to spend a lot of time at this stage of the VR
technology in answering questions about the modes and fidelity of sensory
input and detection of motor output. I think that's easier to do if we
keep the model we use as close as we can to the reality which the users
already know.
I agree that the reality we can generate in a reasonable amount of time
(say with display frame rates of 10 / second, and stimulus-response delays
of no more than 100 milliseconds) on comomonly available computers is not
going to allow high-fidelity "reality", with radiosity-shading and
force-feedback on every finger joint. And for the pioneering work which
will be done in the next two or three years "reality" will be limited by
the small number of people working in the field, and their inability to do
it all themselves. But I think the minimum useful set of physical
phenomena is larger than most of us here seem to think (one of my pet
peeves is the way many people completely ignore sound, both as input and
output), and I also think that a good choice of development platform for a
VR system would make much of the existing display and simulation software
easily available. But that's for another thread of discussion.
> Bruce Cohen [brucec@tekcrl.labs.tek.com] writes:
>>I think this is a very limited and limiting view of the way the designer
>>and inhabitants of a virtual reality interact. The implication is that a
>>world is finished and perfect construct, whose designer has considered
>>every interaction possible, and knows the nature of every use to which the
>>world will be put (or even most of them). This is not the way complex
>>systems are introduced in the "real world". Often, particularly in
>>systems with complex user interfaces, new interactions and new applications
>>for the system come to light for years after the designer has gone on to
>>other projects.
>
> I'm sorry if I gave this impression, that was not what I meant, and I
> agree with you that any system as complex as a world-wide network of
> VR machines would be impossible to analyse completely. I was looking
> more from the point of view that when a new 'room' comes on-line, it is
> the responsibility of the designer to ensure that only the people he
> wants in are allowed in (see further below).
>
This is more an issue of security than object design. I make that
distinction because I believe that it should be possible to design an
object to work in an unsecure environment, and then, as a completely
independent operation, install one instance of it in a secure environment,
and another in a less secure environment. In other words, objects should
not contain policy which controls access to them, they should only contain
mechanism which provides the access.
> But take another example I came across the other day (from
> a famous book I borrowed of a friend over a drink for 10 minutes, so I'm
> not accurate [from Mind Children by Hans Moravek]) that is basically a
> school, or a VR, AI text book. It gives you individual tuition (on a
> time-sharing basis) and even allows you to interact with other students
> so you can choose to learn together or on your own. Not in a school, but
> walking along an orchard path with Isaac Newton to learn about gravity
> and mass, or in a train to learn about the Doppler effect, and relativity
> with Einstein (or, at least, VR AI interpretations of them). Now you
> *don't* want people messing around, they have a limited set of allowable
> actions. They won't bring anything with them, and they probably won't
> take objects away. Each VR environment will have it's own set of
> constraints on what can and cannot be done, and collaboration is merely
> one example of one set of 'constraints'.
>
Again, I consider this a use issue, not a design issue. In other words,
the designer provides a way for you to allow or disallow others from using
your instances of the objects, you decide who gets to use them and how. In
the meantime, I get to make different decisions about my instances of the
objects.
> To explain my point in
> this context, if I were denied access to a room by some security software,
> it would be in the best interests of the software to not even inform
> me of the existence of the room. i.e. on entering an area I must
> identify myself and then the software informs me of what it wants me
> to know. (see below)
>
That may be the way you want your doors to work. But if we both buy doors
from the Acme Virtual Door Company, and you want yours only to appear to
your friends, whereas I want mine to appear to everybody, but be locked
between 12 and 4 everyday, and have a sign on it to that effect, I don't
want to have your behavior wired into my door.
> 1) The universe (as we know it) is consistent only on a macro level.
> Half of the study in nuclear physics is currently revolving
> around Quanta (i.e. the *probability* that if cause A occurs
> effect B will seen rather than effect C).
This gets a little astray, but I don't think this statement is true. QM is
perfectly consistent, they're just not deterministic. The difference is
between whether the underlying world works so that one set of rules never
causes something ruled out by another set (consistency), and whether the
outcome of some set of events is completely controlled by the past history
of events along any worldlines entering the events (determinism).
> 2) To model the real-world we would need to model the non-perceptible
> parts of the world as well. i.e. Solar radiation (non-perceptible,
> at least without instruments) acts on the upper atmosphere
> (non-perceptible, unless you happen to be there) and the Magnetosphere
> (non-perceptible) to produce the Aurora Borealis, which *is*
> perceptible.
As I said before, I think this is where we got confused. I'm not
advocating modelling everything. I may take up the question of what
constitutes the appropriate granularity of the world we need to simulate in
a later posting, but right now, let me just say that we don't have to even
model everything which is perceptible, and those things we do model may be
simplified.
> True, but when computers hit the market for the first time, there were
> very few experienced users. When cars hit the market for the first time,
> no one could drive. People *do* learn (when motivated).
>
True, but what motivates them? Why should the average computer user (who
according to everything I've seen uses at most one word processing program,
one calendar, and one spread-sheet, running on DOS) use VR? I contend that
the reason for developing VR in the first place is to find ways of better
presenting the computer's power to the average user, and I specifically
reject the argument that they'll learn to use it because they have to. Which
is to say that a kind word works better than a gun :-).
>> <I said>:
>> 6) I suspect we'll learn more about what we can do to modify VR models
>> from letting the VR inhabitants mess around with the rules than any
>> other way. That means starting with a baseline, and giving users
>> the tools to modify it incrementally. Along the way, we have to
>> learn how to reconcile conflicting world-views as well.
>
> Now this I don't understand. From your point of view, if it is a good
> model of reality, how is it possible to have conflicting world-views
> (other than psychologically). From my point of view, every gets there
> own individual world view, just the same as you get your own individual
> copy of this article. Please elaborate.
>
What I meant here was that each user could customize the interface to the
system so as to see common objects in different ways, like having multiple
views of the same text, with different fonts and formatting, in different
windows. The problem is reconciling the effects of actions by the users on
the objects, such that an operation which one user can perform has a
visible and comprehensible result on the view of the object which another
user has. What makes this complicated is that the operations may be
abstract actions which affect the meaning of the object to the user, and be
translated into the object's attributes in subtle and indirect ways. A
poor example that comes to me offhand is one user opening the manila folder
which represents a container of data files which in this view are pieces of
"paper", while being watched by another user who sees data files as
simulated terminal screens.
--
---------------------------------------------------------------------------
Speaker-to-managers, aka
Bruce Cohen, Computer Research Lab email: brucec@tekcrl.labs.tek.com
Tektronix Laboratories, Tektronix, Inc. phone: (503)627-5241
M/S 50-662, P.O. Box 500, Beaverton, OR 97077heuring@ncar.UCAR.EDU (Vincent Heuring) (10/18/90)
In article <8514@milton.u.washington.edu> mike@x.co.uk (Mike Moore) writes: >>Mike Moore (i.e. me) writes: >>> What I'm saying is that >>> in a VR environment if we don't want people entering a room, we don't >>> even tell them it's there, they just see a blank wall (or one with >>> pictures hung on it, or whatever) and all the hacking in the world won't >>> change that fact. For people we do want to allow in there is simply an >>> entry point, no messing around with doors just a 'transporter' machine/ >>> object which moves you into the chosen room/building/area/'country', >>> wherever you intend going. >>"transporter machine" is still a door in terms of its affordances. > Consistency is a virtue. In VR, it may be a virtual virtue, but a virtue nonetheless. It is inconsistent in VR and in the database to permit only a certain class of user see the door. It is sufficient to allow all to percieve the door, but only a subclass open it. Let the database be consistent, not changing for each class of user. > To explain my point in >this context, if I were denied access to a room by some security software, >it would be in the best interests of the software to not even inform >me of the existence of the room. Hang the best interests of the software. If the system security is inadequate, *that* is what should be addressed. This is analogous to unix showing all directories at a given node, including their permissions. drwx------ is a door closed to all except the owner of the room within. Certainly this is to be preferred to a system where users can't even see dir entries that they am not permitted to. The system has to have consistency, whether it is unix or VR. >Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>But this begs the question. If the objects in the room don't shout at you, >>how do you know they're there? >>How do you know what you can do with >>them? You look around. If you percieve an object, you poke it, or squeeze it, or try to pick it up, twist it's knobs -- you get the point. If it happens to be a door, you try the knob. If it doesn't turn, you give up. Maybe the door has a sign on it that says ECE 553 - Programming Language Theory Class Members Only --- Vincent Heuring Dep't of Electrical & Computer Engineering University of Colorado - Boulder heuring@boulder.Colorado.EDU
brucec%phoebus.labs.tek.com@RELAY.CS.NET (Bruce Cohen;;50-662;LP=A;) (10/18/90)
In article <9461@milton.u.washington.edu> boulder!boulder!heuring@ncar.UCAR.EDU (Vincent Heuring) writes: > >>Buckaroo Banzai [wex@dali.pws.bull.com] writes: >>>But this begs the question. If the objects in the room don't shout at you, >>>how do you know they're there? >>>How do you know what you can do with >>>them? > > > You look around. If you percieve an object, you poke it, or squeeze it, > or try to pick it up, twist it's knobs -- you get the point. If it > happens to be a door, you try the knob. If it doesn't turn, you give up. > Maybe the door has a sign on it that says Ok, that works in real life because there's a lot of light zipping around the room, bouncing off things and reaching your eyes. Now, how does the VR interface software, running on you trusty home computer, know what's in a room which resides on a database on a remote machine in another city? I think this was the sort of question that this thread of discussion started with. Clearly, there's some level of structure you are interested in perceiving immediately when you enter a room, and some you want to see (and hear and touch) only if you examine things closely. FOr instance, you want to see a table in the corner, but may be you don't care about (or at this distance your virtual sight can't resolve) the detail of the wood grain in the legs of the table. To make perception in a virtual world anything like real perception, that is, with variable level of detail at varying distances, the ability to focus on specific areas while ignoring detail in others, the interface between the world and the interface, which is the agent which represents a user in the virtual world, must relate to the objects around it in ways which mimic the ways we relate to the objects around us. That's not to say that we have perceive VR exactly as we perceive RR ("real reality" :-)). If you like, you can change the parameters of your focus to work like an eagle, which can resolve amazing detail on distant objects, but trades off coarser detail on the wide field. These issues get very interesting when you try to optimize the use of processing power by concentrating it on the details the user is actually looking at right now, and fudging the rest. But that's for another thread of discussion. -- --------------------------------------------------------------------------- Speaker-to-managers, aka Bruce Cohen, Computer Research Lab email: brucec@tekcrl.labs.tek.com Tektronix Laboratories, Tektronix, Inc. phone: (503)627-5241 M/S 50-662, P.O. Box 500, Beaverton, OR 97077