Virtual reality

This article is about the simulation technology. For the Alan Ayckbourn play, see Virtual Reality (play). For the gamebook series, see Virtual Reality (gamebooks)

Virtual reality (VR) is a technology which allows a user to interact with a computer-simulated environment, be it a real or imagined one. Most current virtual reality environments are primarily visual experiences, displayed either on a computer screen or through special or stereoscopic displays, but some simulations include additional sensory information, such as sound through speakers or headphones. Some advanced, haptic systems now include tactile information, generally known as force feedback, in medical and gaming applications. Users can interact with a virtual environment or a virtual artifact (VA) either through the use of standard input devices such as a keyboard and mouse, or through multimodal devices such as a wired glove, the Polhemus boom arm, and omnidirectional treadmill. The simulated environment can be similar to the real world, for example, simulations for pilot or combat training, or it can differ significantly from reality, as in VR games. In practice, it is currently very difficult to create a high-fidelity virtual reality experience, due largely to technical limitations on processing power, image resolution and communication bandwidth. However, those limitations are expected to eventually be overcome as processor, imaging and data communication technologies become more powerful and cost-effective over time.

Virtual Reality is often used to describe a wide variety of applications, commonly associated with its immersive, highly visual, 3D environments. The development of CAD software, graphics hardware acceleration, head mounted displays, database gloves and miniaturization have helped popularize the notion. In the book The Metaphysics of Virtual Reality, Michael Heim identifies seven different concepts of Virtual Reality: simulation, interaction, artificiality, immersion, telepresence, full-body immersion, and network communication. The definition still has a certain futuristic romanticism attached. People often identify VR with Head Mounted Displays, Data Suits and Steven King's The Lawnmower Man.

U.S. Navy personnel using a VR parachute trainer

Background

Terminology

The term artificial reality, coined by Myron Krueger, has been in use since the 1970s but the origin of the term virtual reality is uncertain. It has been credited to The Judas Mandala, a 1982 science fiction novel by Damien Broderick, where the context of use is somewhat different from that defined above. The earliest use cited by the Oxford English Dictionary is in a 1987 article entitled "Virtual reality", but the article is not about VR technology. The VR developer Jaron Lanier claims that he coined the term. The concept of virtual reality was popularized in mass media by movies such as Brainstorm and The Lawnmower Man (and others mentioned below), and the VR research boom of the 1990s was motivated in part by the non-fiction book Virtual Reality by Howard Rheingold. The book served to demystify the subject, making it more accessible to less technical researchers and enthusiasts, with an impact similar to what his book The Virtual Community had on virtual community research lines closely related to VR. Multimedia: from Wagner to Virtual Reality, edited by Randall Packer and Ken Jordan and first published in 2001, explores the term and its history from an avant-garde perspective.

Timeline

Morton Heilig wrote in the 1950s of an "Experience Theatre" that could encompass all the senses in an effective manner, thus drawing the viewer into the onscreen activity. He built a prototype of his vision dubbed the Sensorama in 1962, along with five short films to be displayed in it while engaging multiple senses (sight, sound, smell, and touch). Predating digital computing, the Sensorama was a mechanical device, which reportedly still functions today. In 1968, Ivan Sutherland, with the help of his student Bob Sproull, created what is widely considered to be the first virtual reality and augmented reality (AR) head mounted display (HMD) system. It was primitive both in terms of user interface and realism, and the HMD to be worn by the user was so heavy it had to be suspended from the ceiling, and the graphics comprising the virtual environment were simple wireframe model rooms. The formidable appearance of the device inspired its name, The Sword of Damocles. Also notable among the earlier hypermedia and virtual reality systems was the Aspen Movie Map, which was created at MIT in 1977. The program was a crude virtual simulation of Aspen, Colorado in which users could wander the streets in one of three modes: summer, winter, and polygons. The first two were based on photographs — the researchers actually photographed every possible movement through the city's street grid in both seasons — and the third was a basic 3-D model of the city. In the late 1980s the term "virtual reality" was popularized by Jaron Lanier, one of the modern pioneers of the field. Lanier had founded the company VPL Research (from "Virtual Programming Languages") in 1985, which developed and built some of the seminal "goggles n' gloves" systems of that decade.

Future

It is unclear exactly where the future of virtual reality is heading. In the short run, the graphics displayed in the HMD will soon reach a point of near realism. The audio capabilities will move into a new realm of three dimensional sound. This refers to the addition of sound channels both above and below the individual or a Holophony approach.

Within existing technological limits, sight and sound are the two senses which best lend themselves to high quality simulation. There are however attempts being currently made to simulate smell. The purpose of current research is linked to a project aimed at treating Post Traumatic Stress Disorder (PTSD) in veterans by exposing them to combat simulations, complete with smells. Although it is often seen in the context of entertainment by popular culture, this illustrates the point that the future of VR is very much tied into therapeutic, training, and engineering demands. Given that fact, a full sensory immersion beyond basic tactile feedback, sight, sound, and smell is unlikely to be a goal in the industry. It is worth mentioning that simulating smells, while it can be done very realistically, requires costly research and development to make each odor, and the machine itself is expensive and specialized, using capsules tailor made for it. Thus far basic, and very strong smells such as burning rubber, cordite, gasoline fumes, and so-forth have been made. Something complex such as a food product or specific flower would be prohibitively expensive (see the perfume industry as an example).

Not content to serve only its customers' eyes and ears, Japan's NTT Communications, of Tokyo, has just finished testing an Internet-connected odor-delivery system to be used by retailers and restaurants to attract customers. Whether NTT has sniffed out a new commercial opportunity or this attempt to engage our olfactory sense will fail the smell test is too early to judge. But as new trials and applications are tried out and more data gathered, Hamada says he is sure the technology “will take communications to a new level in content richness, compared to today’s communications, which only offers images and sounds”.

In order to engage the other sense of taste, the brain must be manipulated directly. This would move virtual reality into the realm of simulated reality like the "head-plugs" used in The Matrix. Although no form of this has been seriously developed at this point, Sony has taken the first step. On April 7, 2005, Sony went public with the information that they had filed for and received a patent for the idea of the non-invasive beaming of different frequencies and patterns of ultrasonic waves directly into the brain to recreate all five senses. There has been research to show that this is possible . Sony has not conducted any tests as of yet and says that it is still only an idea.

It has long been feared that Virtual Reality will be the last invention of humans, as once simulations become cheaper and more widespread, no one will ever want to leave their "perfect" fantasies. Satirists, however, have nodded towards humans' aversion to catheters and starvation.

Impact

There has been increasing interest in the potential social impact of new technologies, such as virtual reality (as may be seen in utopian literature, within the social sciences, and in popular culture). Mychilo S. Cline, in his book, Power, Madness, and Immortality: The Future of Virtual Reality, argues that virtual reality will lead to a number of important changes in human life and activity. He argues that:

• Virtual reality will be integrated into daily life and activity and will be used in various human ways.
• Techniques will be developed to influence human behavior, interpersonal communication, and cognition (i.e., virtual genetics).
• As we spend more and more time in virtual space, there will be a gradual “migration to virtual space,” resulting in important changes in economics, worldview, and culture.
• The design of virtual environments may be used to extend basic human rights into virtual space, to promote human freedom and well-being, and to promote social stability as we move from one stage in socio-political development to the next.

Heritage and Archaeology

The use of VR in Heritage and Archaeology has enormous potential in museum and visitor centre applications, but its use has been tempered by the difficulty in presenting a 'quick to learn' real time experience to numerous people any given time. Many historic reconstructions tend to be in a pre-rendered format to a shared video display, thus allowing more than one person to view a computer generated world, but limiting the interaction that full-scale VR can provide. The first use of a VR presentation in a Heritage application was in 1994 when a museum visitor interpretation provided an interactive 'walk-through' of a 3D reconstruction of Dudley Castle in England as it was in 1550. This comprised of a computer controlled laserdisc based system designed by British based engineer Colin Johnson. It is a little known fact that one of the first users of Virtual Reality was Her Majesty Queen Elizabeth II, when she officially opened the visitor centre in June 1994. Details of the original project can be viewed here:Virtual Tours of Dudley Castle archive. The system featured in a conference held by the British Museum in November 1994 and in the subsequent technical paper.. 'Imaging the Past' - Electronic Imaging and Computer Graphics in Museums and Archaeology - ISBN 0861591143.

Virtual Reality Reproduction

Virtual Reality enables heritage sites to be recreated extremely accurately, so that the recreations can be published in various media. The original sites are often inaccessible to the public, or may even no longer exist. This technology can be used to develop virtual reproductions of caves, natural environment, old towns, monuments, sculptures and archaeological elements.

The process that Virtualware has used to reproduce the natural cave of Santimamiñe is based on the following main steps: Data collection in the area through a 3D laser scanning and photogrammetry, Data processing in cabinet, Virtual model generation, Application development, Design and an installation and setting up of the Virtual Reality system. A video sample of the results of this technology can be viewed in virtual-caves.com

Mass media

Mass media has been a great advocate and perhaps a great hindrance to its development over the years. During the research “boom” of the late 1980s into the 1990s the news media’s prognostication on the potential of VR — and potential overexposure in publishing the predictions of anyone who had one (whether or not that person had a true perspective on the technology and its limits) — built up the expectations of the technology so high as to be impossible to achieve under the technology then or any technology to date. Entertainment media reinforced these concepts with futuristic imagery many generations beyond contemporary capabilities.

Fiction books

Many science fiction books and movies have imagined characters being "trapped in virtual reality". One of the first modern works to use this idea was Daniel F. Galouye's novel Simulacron-3, which was made into a German teleplay titled Welt am Draht ("World on a Wire") in 1973 and into a movie titled The Thirteenth Floor in 1999. Other science fiction books have promoted the idea of virtual reality as a partial, but not total, substitution for the misery of reality (in the sense that a pauper in the real world can be a prince in VR), or have touted it as a method for creating breathtaking virtual worlds in which one may escape from Earth's now toxic atmosphere. They are not aware of this, because their minds exist within a shared, idealized virtual world known as Dream Earth, where they grow up, live, and die, never knowing the world they live in is but a dream. Stanislaw Lem wrote in early 1960 a short story "dziwne skrzynie profesora Corcorana" in which he presented a scientist, who devised a completely artificial virtual reality. Amongst the beings trapped inside his created virtual world, there is also a scientist, who also devised such machines creating another level of virtual world.

The Piers Anthony novel Killobyte follows the story of a paralysed cop trapped in a virtual reality game by a hacker, whom he must stop to save a fellow trapped player with diabetes slowly succumbing to insulin shock. This novel toys with the idea of both the potential positive therapeutic uses, such as allowing the paralysed to experience the illusion of movement while stimulating unused muscles, as well as virtual realities' dangers.

An early short science fiction story — "The Veldt" — about an all too real "virtual reality" was included in the 1951 book The Illustrated Man, by Ray Bradbury and may be the first fictional work to fully describe the concept.

The Otherland series of 4 novels by Tad Williams . Set in the 2070s, it shows a world where the Internet has become accessible via virtual reality and has become so popular and somewhat commonplace that, with the help of surgical implants, people can connect directly into this future VR environment. The series follows the tale of a group of people who, while investigating a mysterious illness attacking children while in VR, find themselves trapped in a virtual reality system of fantastic detail and sophistication unlike any the world has ever imagined.

Other popular fictional works that use the concept of virtual reality include William Gibson's Neuromancer which defined the concept of cyberspace, Neal Stephenson's Snow Crash, in which he made extensive reference to the term "avatar" to describe one's representation in a virtual world, and Rudy Rucker's The Hacker and the Ants, in which programmer Jerzy Rugby uses VR for robot design and testing.

Another use of VR is in the teenage book "The Reality Bug" by D.J MacHale, where the inhabitants of a territory can have their own perfect virtual world, causing everyone to neglect the real world. To cause everyone to spend less time there, a virus is introduced that should make it slightly less than perfect. However, it is so powerful introduces their worse nightmares, and eventually physically breaks out of the computer until it is shut down.

Alexander Besher's Rim: A Novel of Virtual Reality is similar to Otherland, however it also shows the urban decay that obsession with VR has caused, and the devastating effects to the economy it causes after a major crash leaves millions of users in a coma and some dead.

Television

Perhaps the earliest example of virtual reality on television is a Doctor Who serial "The Deadly Assassin". This story, first broadcast in 1976, introduced a dream-like computer-generated reality known as the Matrix (no relation to the film — see below). The first major American television series to showcase virtual reality was Star Trek: The Next Generation. They featured the holodeck, a virtual reality facility on starships, that enabled its users to recreate and experience anything they wanted. One difference from current virtual reality technology, however, was that replicators, force fields, holograms, and transporters were used to actually recreate and place objects in the holodeck, rather than relying solely on the illusion of physical objects, as is done today.

In Japan and Hong Kong, the first anime series to use the idea of virtual reality was Video Warrior Laserion (1984).

An anime series known as Lain:Serial Experiments included a virtual reality world known as "The Wired" that eventually co-existed with the real world.

Channel 4's Gamesmaster (1992 – 1998) also used a VR headset in its "tips and cheats" segment.

BBC 2's Cyberzone (1993) was the first true "virtual reality" game show. It was presented by Craig Charles.

FOX's VR.5 (1995) starring Lori Singer and David McCallum, used what appeared to be mistakes in technology as part of the show's on-going mystery.

In 2002, Series 4 of hit New Zealand teen sci-fi TV Series, The Tribe featured the arrival of a new tribe to the city, The Technos. They tried to gain power by introducing Virtual Reality to the city. The tribes would battle each other in the Virtual World in a "game" designed by the leader of The Techno's, Ram. However, the effects of VR on the people turned nasty when they started to fight in the real world as well, after too much use made them unable to tell the difference between what was real and what was virtual.

In 2005, Brazilian's Globo TV features a show where VR helmets are used by the attending audience in a space simulation called Conquista de Titã, broadcasted for more than 20 million viewers weekly.

In the anime version of Yu-Gi-Oh!, one three-part episode sees the heroes entering a virtual world based on the game Duel Monsters, where the players must use their cards to work their way through a series of story-based challenges, including simulated monsters. Later, another anime-only arc forces the heroes to enter another virtual world, similar in concept but with a different set of rules. In both arcs, the bodies of the humans entering the virtual world are confined to special pods for the duration of their stay there.

The Popular .hack multimedia franchise is based on a virtual reality MMORPG ironically dubbed "The World"

The French animated series Code Lyoko is based around the virtual world of Lyoko and the Internet, the virtual world is accessed by large scanners which use an atomic process which breaks down the atoms of the person inside, digitalizes them and recreates an incarnation on Lyoko.

Motion pictures

Steven Lisberger's 1982 movie TRON was the first mainstream Hollywood picture to explore the idea. One year later, it would be more fully expanded in the Natalie Wood film Brainstorm. Probably the most famous film to popularize the subject was more recently done by the Wachowski brothers in 1999's The Matrix. The Matrix was significant in that it presented virtual reality and reality as often overlapping, and sometimes indistinguishable. Total Recall and David Cronenberg's film EXistenZ dealt with the danger of confusion between reality and virtual reality in computer games. Cyberspace became something that most movies completely misunderstood, as seen in The Lawnmower Man. Also, the British comedy Red Dwarf used in several episodes the idea that life (or at least the life seen on the show) is a virtual reality game. This idea was also used in Spy Kids 3-D: Game Over. Another movie that has a bizarre theme is Brainscan, where the point of the game is to be a virtual killer. A more artistic and philosophical perspective on the subject can be seen in Avalon. One of the non-Sci Fi movies that uses VR as a story driver is 1994's Disclosure, starring Michael Douglas and based on the Michael Crichton book of the same name. A VR headset is used as a navigating device for a prototype computer filing system. There is also a film from 1995 called "Virtuosity" with Denzel Washington and Russell Crowe that dealt with the creation of a serial killer, used to train law enforcement personnel, that escapes his virtual reality into the real world. ''Johnny Mnemonic'' uses extensive VR, depicting Keanu Reeves playing a "cyber-courier" (Johnny Mnemonic) who smugles data in his brain around the world, in the movie multiple characters have implant allowing them to, for example store information, a funny line is where Keanu brags about havin X (believing it's 40) amounts og GB's available in his brain.

Music videos

The lengthy video for hard rock band Aerosmith's 1993 single "Amazing" depicted virtual reality, going so far as to show two young people participating in virtual reality simultaneously from their separate personal computers (while not knowing the other was also participating in it) in which the two engage in a steamy makeout session, sky-dive, and embark on a motorcycle journey together.

Games

In 1991, the company (originally W Industries, later renamed) Virtuality licenced the Amiga 3000 for use in their VR machines and released a VR gaming system called the 1000CS. This was a stand-up immersive HMD platform with a tracked 3D joystick. The system featured several VR games including Dactyl Nightmare (shoot-em-up), Legend Quest (adventure and fantasy), Hero (VR puzzle), Grid Busters (shoot-em-up). Virtual Reality I Glasses Personal Display System is a visor and headphones headset that is compatible with any video input including 3D broadcasting, and usable with most game systems (Nintendo, PlayStation, etc.). Virtual Reality World 3D Color Ninja game comes with headset visor and ankle and wrist straps that sense the player's punches and kicks. Virtual Reality Wireless TV Tennis Game comes with a toy tennis racket that senses the player's swing, while Wireless TV Virtual Reality Boxing includes boxing gloves that the player wears and jabs with. Nintendo's Virtual Boy was sold for only one year, 1995. Bob Ladrach brought Virtual Knight into the major theme park arcades in 1994. Aura Interactor Virtual Reality Game Wear is a chest and back harness through which the player can feel punches, explosions, kicks, uppercuts, slam-dunks, crashes, and bodyblows. It works with Sega Genesis and Super Nintendo.

In the Mage: The Ascension role-playing game, the mage tradition of the Virtual Adepts is presented as the real creators of VR. The Adepts' ultimate objective is to move into virtual reality, scrapping their physical bodies in favour of improved virtual ones. Also, the .hack series centers on a virtual reality video game. This shows the potentially dangerous side of virtual reality, demonstrating the adverse effects on human health and possible viruses, including a comatose state that some players assume. Metal Gear Solid bases heavily on VR usage, either as a part of the plot, or simply to guide the players through training sessions. In Kingdom Hearts II, the character Roxas lives in a virtual Twilight Town until he merges with Sora. In System Shock, the player has implants making him able to enter into a kind of cyberspace. Its sequel, System Shock 2 also features some minor levels of VR. In Black and White users could download a patch to use the P5 glove to control the game.

Attractions

The developer of theme park style attractions using Virtual Reality technology was a major part of the development of the hardware - moving beyond simulation towards a immersive entertainment experience. Of all these developments, the Walt Disney 'DisneyQuest' venue is the major conceptual application - still operation in 2007.

Fine Art

David Em was the first fine artist to create navigable virtual worlds in the 1970s. His early work was done on mainframes at III, JPL and Cal Tech. Jeffrey Shaw explored the potential of VR in fine arts with early works like Legible City (1989), Virtual Museum (1991), Golden Calf(1994). Canadian artist Char Davies created immersive VR art pieces Osmose (1995) and Ephémère (1998). Maurice Benayoun's work introduced metaphorical, philosophical or political content, combining VR, network, generation and intelligent agents, in works like Is God Flat (1994), The Tunnel under the Atlantic (1995), World Skin (1997). Other pioneering artists working in VR have included Rita Addison, Rebecca Allen, Perry Hoberman, Jacki Morie, and Brenda Laurel.

Marketing

A side effect of the chic image that has been cultivated for virtual reality in the media is that advertising and merchandise have been associated with VR over the years to take advantage of the buzz. This is often seen in product tie-ins with cross-media properties, especially gaming licenses, with varying degrees of success. The NES Power Glove by Mattel from the 1980s was an early example as well as the U-Force and later, the Sega Activator. Marketing ties between VR and video games are to be expected, given that much of the progress in 3D computer graphics and virtual environment development (traditional hallmarks of VR) has been driven by the gaming industry over the last decade. TV commercials featuring VR have also been made for other products, however, such as Nike's "Virtual Andre" in 1997, featuring a teenager playing tennis using a goggle and gloves system against a computer generated Andre Agassi.

Health care education

While its use is still not widespread, virtual reality is finding its way into the training of health care professionals. Use ranges from anatomy instruction (example) to surgery simulation (example). Annual conferences are held to examine the latest research in utilizing virtual reality in the medical fields.

Therapeutic uses

The primary use of VR in a therapeutic role is its application to various forms of exposure therapy, ranging from phobia treatments, to newer approaches to treating PTSD. A very basic VR simulation with simple sight and sound models has been shown to be invaluable in phobia treatment (notable examples would be various zoophobias, and acrophobia) as a step between basic exposure therapy such as the use of simulacra and true exposure. A much more recent application is being piloted by the U.S. Navy to use a much more complex simulation to immerse veterans (specifically of Iraq) suffering from PTSD in simulations of urban combat settings. While this sounds counterintuitive, talk therapy has limited benefits for people with PTSD, which is now thought by many to be a result of changes either to the limbic system in particular, or a systemic change in stress response. Much as in phobia treatment, exposure to the subject of the trauma or fear seems to lead to desensitization, and a significant reduction in symptoms. Some information on this can be found at this Businessweek article as well as this Office of Naval Research article.

Manufacturing

Virtual reality can serve to new product design, helping as an ancillary tool for engineering in manufacturing processes, new product prototype and simulation. Among other examples, we may also quote Electronic Design Automation, CAD, Finite Element Analysis, and Computer Aided Manufacturing. The use of Stereolithography and 3D printing shows how computer graphics modeling can be applied to create physical parts of real objects used in naval, aerospace and automotive industry. Beyond modeling assembly parts, 3D computer graphics techniques are currently used in the research and development of medical devices for innovative therapies, treatments, patient monitoring, and early diagnosis of complex diseases.

Implementation

To develop a real time virtual environment, a computer graphics library can be used as embedded resource coupled with a common programming language, such as C++, Perl, Java or Python. Some of the most popular computer graphics library/API/language are OpenGL, Direct3D, Java3D and VRML, and their use will be directly influenced by the system demands in terms of performance, program purpose, and hardware platform. The use of multithreading (e.g. Posix) can also accelerate 3D performance and enable cluster computing with multi-user interactivity.

Challenges

Virtual reality has been heavily criticized for being an inefficient method for navigating non-geographical information. At present, the idea of ubiquitous computing is very popular in user interface design, and this may be seen as a reaction against VR and its problems. In reality, these two kinds of interfaces have totally different goals and are complementary. The goal of ubiquitous computing is to bring the computer into the user's world, rather than force the user to go inside the computer. The current trend in VR is actually to merge the two user interfaces to create a fully immersive and integrated experience. See simulated reality for a discussion of what might have to be considered if a flawless virtual reality technology was possible. Another obstacle is the headaches due to eye strain, caused by VR headsets. RSI can also result from repeated use of the handset gloves.

Pioneers and notables

Maurice Benayoun Mark Bolas Fred Brooks James H. Clark Doug Church Char Davies Tom DeFanti David Em Scott Fisher Thomas A. Furness III William Gibson

Morton Heilig Myron Krueger Jaron Lanier Brenda Laurel Randy Pausch Mark Pesce Warren Robinett Dan Sandin Susumu Tachi Ivan Sutherland

See also

3DMLW Artificial reality Mixed reality Augmented reality Augmented virtuality Interactive Art Virtuality Continuum CAVE - Cave Automatic Virtual Environment Consensus reality Computer graphics Computer representation of surfaces Cyberspace Dotsoul

First-person shooter Geowall Geoweb Head Mounted Display Hyperreality Metaverse Methods of virtual reality Narrative environment Omnidirectional treadmill Parallel rendering QuickTime VR VR Photography Second Life

Simulated Reality Virtual artifact Virtual Boy Virtual tour Virtual Reality Modelling Language Virtual retinal display Virtual globe Virtual facility VirtuSphere V-business X3D XVROS

References

Bibliography

• Brooks Jr., F. P. (1999). "What's Real About Virtual Reality?", IEEE Computer Graphics And Applications, 19(6), 16
• Burdea, G. and P. Coffet (2003). Virtual Reality Technology, Second Edition. Wiley-IEEE Press.
• Hillis, Ken (1999). Digital Sensations: Space, Identity and Embodiment in Virtual Reality. University of Minnesota Press, Minneapolis, MN.
• Kalawsky, R. S. (1993). The Science of Virtual Reality and Virtual Environments: A Technical, Scientific and Engineering Reference on Virtual Environments, Addison-Wesley, Wokingham, England ; Reading, Mass.
• Kelly, K., A. Heilbrun and B. Stacks (1989). "Virtual Reality; an Interview with Jaron Lanier", Whole Earth Review, Fall 1989, no. 64, pp. 108(12)
• Krueger, M. W. (1991). Artificial Reality II, Addison-Wesley, Reading, Massachusetts
• Lanier, J., and F. Biocca (1992). "An Insider's View of the Future of Virtual Reality." Journal of Communication, 42(4), 150
• Packer, Randall, and Ken Jordan (eds). 2002. Multimedia: From Wagner to Virtual Reality, Expanded Edition. W.W. Norton.
• Packer, Randall, and Ken Jordan (eds). 2000. Virtual Art Museum - Multimedia: From Wagner to Virtual Reality
• Rheingold, H. (1992). Virtual Reality, Simon & Schuster, New York, N.Y.
• Robinett, W. (1994). "Interactivity and Individual Viewpoint in Shared Virtual Worlds: The Big Screen vs. Networked Personal Displays." Computer Graphics, 28(2), 127
• Slater, M., Usoh, M.(1993). “The Influence of a Virtual Body on Presence in Immersive Virtual Environments” Virtual Reality International 93, Proceedings of the Third Annual Conference on Virtual Reality, London, April 1993, pages 34--42. Meckler, 1993
• Stanney, K. M. ed. (2002). Handbook of Virtual Environments: Design, Implementation, and Applications. Lawrence Erlbaum Associates, Inc., Mahwah, New Jersey
• Sutherland, I. E. (1965). "The Ultimate Display". Proceedings of IFIP 65, vol 2, pp. 506-508
• Warwick, K., Gray, J. and Roberts, D. eds. (1993). Virtual Reality in Engineering, Peter Peregrinus.
• Goslin, M, and Morie, J. F., (1996). "Virtopia" Emotional experiences in Virtual Environments", Leonardo, vol. 29, no. 2, pp. 95-100.
• Robles-De-La-Torre G. The Importance of the Sense of Touch in Virtual and Real Environments. IEEE Multimedia 13(3), Special issue on Haptic User Interfaces for Multimedia Systems, pp. 24-30 (2006).
• Hayward V, Astley OR, Cruz-Hernandez M, Grant D, Robles-De-La-Torre G. Haptic interfaces and devices. Sensor Review 24(1), pp. 16-29 (2004).
• Monkman. G.J. ‑ An Electrorheological Tactile Display ‑ Presence (Journal of Teleoperators and Virtual Environments) ‑ Vol. 1, issue 2, pp. 219-228, MIT Press, July 1992.
• Monkman. G.J. - 3D Tactile Image Display - Sensor Review - Vol 13, issue 2, pp. 27-31, MCB University Press, April 1993.
• Klein. D, D. Rensink, H. Freimuth, G.J. Monkman, S. Egersdörfer, H. Böse, & M. Baumann - Modelling the Response of a Tactile Array using an Electrorheological Fluids - Journal of Physics D: Applied Physics, vol 37, no. 5, pp794-803, 2004
• Klein. D, H. Freimuth, G.J. Monkman, S. Egersdörfer, A. Meier, H. Böse M. Baumann, H. Ermert & O.T. Bruhns - Electrorheological Tactile Elements. Mechatronics - Vol 15, No 7, pp883-897 - Pergamon, September 2005.

External links

• How Virtual Reality Works at HowStuffWorks