From: John Costella Subject: Re: DESIGN: 3D computing vs. virtual reality: what's the difference? Date: Mon, 11 Dec 1995 12:05:11 +1100 (EETDT) > DESIGN: 3D computing vs. virtual reality: what's the difference? > This seems to be the question of the moment. There will be widespread disagreement on what the various terms mean. With that caveat, let me offer my humble interpretation. (The terms are of course highly cross-connected, so the following linear textual description is quite disordered!) VIRTUAL WORLDS ============== In my mind, "virtual worlds" is the most general, encompassing term covering the sort of stuff we discuss here on sci-vw. In my lexicon, *any* constructed or simulated system that is a metaphor for an *action* in the real world, is a virtual world. A word processing document is not a virtual world. A spreadsheet is not a virtual world. An image of a building is not a virtual world. All of these things are just digital representations of other, more traditional objects in the real world. However, a windowed operating system *is* a (very primitive) virtual world. It is a "desktop metaphor"---translate that to a "virtual desktop world", if you like. If it were just a bitmap of a wooden desk, it would not be a world. But we *interact* with a windowed system in a way that, to some extent, simulates the way we interact with a real desk. Note that the interface devices (mouse, keyboard) are *not* really natural ways of interfacing. But there is still a virtual world in there. Of course, a windowing system is very primitive. Arcade and computer games present, on the whole, a more sophisticated virtual world. Full three-dimensional freedom, sophisticated sounds, and more interesting content make them more entraining. But the interface is often quite poor (e.g., a joystick), except perhaps driving simulators and the like. Nevertheless, they are good virtual worlds. And then we have all of the "higher lifeforms" of virtual worlds, such as what most people here are working with or on. Again, I draw the distinction between *objects* and *actions*. A 3d rendering of some object (real, simulated or imagined) is *not* a virtual world. A movie is not a virtual world. Images of PET and MRI scans are not virtual worlds. But if you can *move* the object around, or move around it; if you can *make* it do things; if you can *interact* with it;---then you have a virtual world. I realise that the meaning I attach to "virtual world" encompasses many, many areas of computing and technology, whose creators would probably not consider to have anything to do with "VR". I see in "virtual worlds" a term that *links* our field with many others---a concept, rather than a specific technology. VIRTUAL REALITY =============== This is a popular term. Bob doesn't like it. I think it serves a useful purpose. People equate "VR" with gloves and goggles. So my view is that we shouldn't try and destroy the awareness the term has; we should use it as one of many terms in our vocabulary. I use "Virtual Reality" to refer to the *specific interfacing technology* used to make our connection to virtual worlds more natural, of a higher bandwidth, more believeable, and more *immersive*. I draw the line somewhere above mice, keyboards, desktop/laptop displays, lightpens, digitisers, and standard SoundBlaster-like sound devices. Most of everything else is VR: shutter glasses, HMD's, gloves, haptic feedback, motion platforms, spatiaised sound, VET's and CAVE's, and so on. I draw the line here not on fundamental grounds, but on historical ones. In Bob's lexicon, my "VR" would be his "virtual worlds technology". Or at least the hardware part of it. I also refer to "virtual reality technology". People can visualise what this means: most think of HMD's; but this can be a useful introductory example to more sophisticated immersive interfaces. Of course, we need to explain this to them. Note that my "VR", in itself, is devoid of content. It is a lump of interfacing technology and protocols, that doesn't in itself do anything useful. Without content, it is a gadget; a novelty. This is *not* a view that should be shunned; it should be proclaimed and preached throughout the land! VR *IS* a toy ... until you connect it to an interesting virtual world. Then it is a amazing. VIRTUAL WORLD SOFTWARE ====================== I don't have a specific term for this. I consider it to be all of "virtual worlds", minus the hardware. This is of course where the real creativity and power comes in. If your virtual world software is just a game, then the best VR hardware in the world just makes it a great immersive game. On the other hand, a well- designed and -executed virtual world system can (and will) make an impact in practically any endeavour of interest and importance. It all depends on *content*. Which is of course what everyone is working on ... 3D COMPUTING ============ This is what Bob's question targetted. In the above scheme of things, 3D computing is practically independent of "VR". 3D computing builds 3D representations of objects. There are both hardware and software aspects to this process. In itself, it is highly useful, profitable, and worthy of praise. In my opinion, once you have the ability to manipulate the objects in your 3D system, you have a 3D virtual world. There is nothing special in this proclamation: a "virtual world" is a concept, not a specific technology. So when I talk to people about their existing 3D systems, I gradually refer to the things "in their virtual world". It is not an alien concept. This is how they have grown to consider their interactive 3D systems anyway. I just surreptitiously give it a name for them. Then there is Virtual Reality. This encompasses the various interface devices that make virtual worlds more immersive. Sometimes you can tack them onto the end of an existing 3D visualisation setup. Often you want to build a better system from the ground up. Either way, it is new technology. But of course the more sophisticated (non-visual) forms of VR technology force system developers to broaden their views on how human-computer interaction should occur. VR consultants have (or should have) the necessary knowledge and contacts to assist in this broadening of perspective. So, in a nutshell, I consider "VR" the technology that makes the "virtual worlds" of "3D computingi" more effective and compelling. Of course, if the people using the 3D computing equipment do not have experience building worlds, they need assistance. Hence the complementary part of the virtual world industry--- the "virtual world software" creators. MULTIMEDIA ========== This is a difficult concept to deal with at the moment, in this country at least, since large sums of money (not usually forthcoming from the Government for such purposes) have been allocated to Multimedia. It has skewed the organisation and implementation of VR. (For example, my proposal for a VR Centre and Services group at the University of Melbourne has been accepted in broad terms, but it seems likely that it will be implemented as a sub-branch of the existing "Multimedia Centre" ... hrghh). I consider Multimedia to be somewhat of a cobbling together of information storage and presentation devices, in a primitive sort of virtual world setting (usually not much better than a windowed operating system). In my humble opinion, it is not really related to virtual worlds very closely at all. Not to say that Multimedia is not excellent in its own right---it serves many purposes wonderfully well; just that (at least what I have seen and used) is more like a convenient and powerful confluence of printed and broadcast information, rather than a creation of any new world as such. Hence I am very reticent to run VR under the banner of a Multimedia Centre. ================================================================= So that's my 2 cents' worth. Fell free, Bob (or anyone else) to use my opinions above for any honourable purpose you like. Again, I emphasise they are highly subjective views of words that many feel strongly about. Let me know if you think I am doing the terms a disservice. (Well maybe except Multimedia :-) John Costella ===================================================================== Dr John P. Costella School of Physics, The University of Melbourne mailto:jpc@physics.unimelb.edu.au http://www.ph.unimelb.edu.au/~jpc Phone: +61 3 9344-5435 Home: +61 3 9768-9268 Fax: +61 3 9347-4783 =====================================================================