Virtual reality

"Virtuality" redirects here. For other uses, see Virtuality (disambiguation).

Not to be confused with Simulated reality.

Researchers with the European Space Agency in Darmstadt, Germany, exploring virtual reality for controlling planetary rovers and satellites in orbit

Virtual reality (VR) is a computer-generated scenario that simulates a realistic experience. The immersive environment can be similar to the real world in order to create a lifelike experience grounded in reality or sci-fi. Augmented reality systems may also be considered a form of VR that layers virtual information over a live camera feed into a headset, or through a smartphone or tablet device.

Current VR technology most commonly uses virtual reality headsets or multi-projected environments, sometimes in combination with physical environments or props, to generate realistic images, sounds and other sensations that simulate a user's physical presence in a virtual or imaginary environment. A person using virtual reality equipment is able to "look around" the artificial world, move around in it, and interact with virtual features or items. The effect is commonly created by VR headsets consisting of a head-mounted display with a small screen in front of the eyes, but can also be created through specially designed rooms with multiple large screens.

VR systems that include transmission of vibrations and other sensations to the user through a game controller or other devices are known as haptic systems. This tactile information is generally known as force feedback in medical, video gaming and military training applications.

Etymology and terminology

File:Linux kernel and gaming input-output latency.svg

Paramount for the sensation of immersion into virtual reality are a high frame rate (at least 95 fps), as well as a low latency.

"Virtual" has had the meaning "being something in essence or effect, though not actually or in fact" since the mid-1400s. The term "virtual" has been used in the computer sense of "not physically existing but made to appear by software" since 1959. In 1938, Antonin Artaud described the illusory nature of characters and objects in the theatre as "la réalité virtuelle" in a collection of essays, Le Théâtre et son double. The English translation of this book, published in 1958 as The Theater and its Double, is the earliest published use of the term "virtual reality". The term "artificial reality", coined by Myron Krueger, has been in use since the 1970s. The term "virtual reality" was first used in a science fiction context in The Judas Mandala, a 1982 novel by Damien Broderick.

A "cyberspace" is a networked virtual reality.

Virtual reality shares some elements with "augmented reality" (or AR). AR is a type of virtual reality technology that blends what the user sees in their real surroundings with digital content generated by computer software. The additional software-generated images with the virtual scene typically enhance how the real surroundings look in some way. Some AR systems use a camera to capture the user's surroundings or some type of display screen which the user looks at (e.g., Microsoft's HoloLens, Magic Leap).

Technology

The Virtual Reality Modelling Language (VRML), first introduced in 1994, was intended for the development of "virtual worlds" without dependency on headsets. The Web3D consortium was subsequently founded in 1997 for the development of industry standards for web-based 3D graphics. The consortium subsequently developed X3D from the VRML framework as an archival, open-source standard for web-based distribution of VR content.

All modern VR displays are based on technology developed for smartphones including: gyroscopes and motion sensors for tracking head, hand, and body positions; small HD screens for stereoscopic displays; and small, lightweight and fast processors. These components led to relative affordability for independent VR developers, and lead to the 2012 Oculus Rift kickstarter offering the first independently developed VR headset.

Independent production of VR images and video has increased by the development of omnidirectional cameras, also known as 360-degree cameras or VR cameras, that have the ability to record in all directions, although at low-resolutions or in highly compressed formats for online streaming. In contrast, photogrammetry is increasingly used to combine several high-resolution photographs for the creation of detailed 3D objects and environments in VR applications.

History

Before the 1950s

File:Sensorama-morton-heilig-virtual-reality-headset.jpg

The Sensorama was released in the 1950s.

File:View-Master with Reel.jpg

View-Master, a stereoscopic visual simulator, was introduced in 1939.

The exact origins of virtual reality are disputed, partly because of how difficult it has been to formulate a definition for the concept of an alternative existence. Elements of virtual reality appeared as early as the 1860s. French avant-garde playwright Antonin Artaud took the view that illusion was not distinct from reality, advocating that spectators at a play should suspend disbelief and regard the drama on stage as reality. The first references to the more modern concept of virtual reality came from science fiction.

Laurence Manning's 1933 series of short stories, "The Men Who Awoke"—later a novel—describes a time when people ask to be connected to a machine that replaces all their senses with electrical impulses and, thus, live a virtual life chosen by them (à la "The Matrix", but voluntary, not imposed).

Stanley G. Weinbaum's 1935 short story "Pygmalion's Spectacles" describes a goggle-based virtual reality system with holographic recording of fictional experiences, including smell and touch.

1950–1970

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. Heilig also developed what he referred to as the "Telesphere Mask" (patented in 1960). The patent application described the device as "a telescopic television apparatus for individual use...The spectator is given a complete sensation of reality, i.e. moving three dimensional images which may be in colour, with 100% peripheral vision, binaural sound, scents and air breezes".

Around the same time, Douglas Engelbart used computer screens both as input and output devices. In 1968, Ivan Sutherland, with the help of his student Bob Sproull, created what was widely considered to be the first head-mounted display (HMD) system for use in immersive simulation applications. It was primitive both in terms of user interface and realism, and the HMD to be worn by the user was so heavy that it had to be suspended from the ceiling. The graphics comprising the virtual environment were simple wire-frame model rooms. The formidable appearance of the device inspired its name, The Sword of Damocles.

1970–1990

File:Musée Mécanique 205.JPG

Battlezone, an arcade video game from 1980, used 3D vector graphics to immerse the player in a VR world.(Atari).

Also notable among the earlier hypermedia and virtual reality systems was the Aspen Movie Map, which was created at MIT in 1978. The program was a crude virtual simulation of Aspen, Colorado in which users could wander the streets in one of the 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. Atari founded a research lab for virtual reality in 1982, but the lab was closed after two years due to Atari Shock (North American video game crash of 1983). However, its hired employees, such as Tom Zimmerman, Scott Fisher, Jaron Lanier and Brenda Laurel, kept their research and development on VR-related technologies. By the 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 in 1985. VPL Research has developed several VR devices like the Data Glove, the Eye Phone, and the Audio Sphere. VPL licensed the Data Glove technology to Mattel, which used it to make an accessory known as the Power Glove. While the Power Glove was hard to use and not popular, at US$75, it was an early affordable VR device.

The VR industry mainly provided VR devices for medical, flight simulation, automobile industry design, and military training purposes from 1970 to 1990.

1990–2000

In 1991, Carolina Cruz-Neira, Daniel J. Sandin and Thomas A. DeFanti from the Electronic Visualization Laboratory created the first cubic immersive room, The Cave. Developed as Cruz-Neira's PhD thesis, it involved a multi-projected environment, similar to the holodeck, allowing people to see their own bodies in relation to others in the room.

In 1992 researcher Louis Rosenberg created the Virtual Fixtures system at the U.S. Air Force’s Armstrong Labs using a full upper-body exoskeleton, enabling a physically realistic virtual reality in 3D. The system enabled the overlay of physically real 3D virtual objects registered with a user's direct view of the real world, producing the first true augmented reality experience enabling sight, sound, and touch.

File:VPL DataSuit 1.jpg

A VPL Research DataSuit, a full-body outfit with sensors for measuring the movement of arms, legs, and trunk. Developed circa 1989. Displayed at the Nissho Iwai showroom in Tokyo

The 1990s saw the first widespread commercial releases of consumer headsets. In 1991, Sega announced the Sega VR headset for arcade games and the Mega Drive console. It used LCD screens in the visor, stereo headphones, and inertial sensors that allowed the system to track and react to the movements of the user's head. In the same year, Virtuality launched and went on to become the first mass-produced, networked, multiplayer VR entertainment system. It was released in many countries, including a dedicated VR arcade at Embarcadero Center in San Francisco. Costing up to $73,000 per multi-pod Virtuality system, they featured headsets and exoskeleton gloves that gave one of the first "immersive" VR experiences. Antonio Medina, a MIT graduate and NASA scientist, designed a virtual reality system to "drive" Mars rovers from Earth in apparent real time despite the substantial delay of Mars-Earth-Mars signals.

In 1991, Computer Gaming World predicted "Affordable VR by 1994". By 1994, Sega released the Sega VR-1 motion simulator arcade attraction, in SegaWorld amusement arcades. It was able to track head movement and featured 3D polygon graphics in stereoscopic 3D, powered by the Sega Model 1 arcade system board. Also in 1994 Apple released QuickTime VR, which, despite using the term "VR", was unable to represent virtual reality, and instead displayed 360 photographic panoramas.

The Virtual Boy was created by Nintendo and was released in Japan on July 21, 1995 and in North America on August 15, 1995. Also in 1995, a group in Seattle created public demonstrations of a "CAVE-like" 270 degree immersive projection room called the Virtual Environment Theater, produced by entrepreneurs Chet Dagit and Bob Jacobson. The same system was shown in 1996 in tradeshow exhibits sponsored by Netscape Communications. Forte released the VFX1, a PC-powered virtual reality headset in 1995, which was supported by games including Descent, Star Wars: Dark Forces, System Shock and Quake.

In 1999, entrepreneur Philip Rosedale formed Linden Lab with an initial focus on the development of VR hardware. In its earliest form, the company struggled to produce a commercial version of "The Rig", which was realized in prototype form as a clunky steel contraption with several computer monitors that users could wear on their shoulders. The concept was later adapted into the personal computer-based, 3D virtual world Second Life.

File:Oculus Rift - Developer Version - Front.jpg

A 2013 developer version of Oculus Rift from Oculus VR, the company Facebook acquired in 2014 for $2 billion

2000–2015

In 2001, SAS3 or SAS Cube became the first PC based cubic room, developed by Z-A Production (Maurice Benayoun, David Nahon), Barco, Clarté, installed in Laval France in April 2001. The SAS library gave birth to Virtools VRPack. By 2007, Google introduced Street View, a service that shows panoramic views of an increasing number of worldwide positions such as roads, indoor buildings and rural areas. It also features a stereoscopic 3D mode, introduced in 2010.

In 2010, Palmer Luckey designed the first prototype of the Oculus Rift. This prototype, built on a shell of another virtual reality headset, was only capable of rotational tracking. However, it boasted a 90-degree field of vision that was previously unseen in the consumer market at the time. This initial design would later serve as a basis from which the later designs came.

In 2013, Valve discovered and freely shared the breakthrough of low-persistence displays which make lag-free and smear-free display of VR content possible. This was adopted by Oculus and was used in all their future headsets.

In early 2014, Valve showed off their SteamSight prototype, the precursor to both consumer headsets released in 2016. It shared major features with the consumer headsets including separate 1K displays per eye, low persistence, positional tracking over a large area, and fresnel lenses.

On March 25, 2014, Facebook purchased Oculus VR for $2 billion. This purchase occurred before any of the devices ordered through Oculus' 2012 Kickstarter had shipped. In that same month, Sony announced Project Morpheus (its code name for PlayStation VR), a virtual reality headset for the PlayStation 4 video game console. Google announces Cardboard, a do-it-yourself stereoscopic viewer for smartphones. The user places their smartphone in the cardboard holder, which they wear on their head. In 2015, the Kickstarter campaign for Gloveone, a pair of gloves providing motion tracking and haptic feedback, was successfully funded, with over $150,000 in contributions.

In February–March 2015, HTC and Valve Corporation announced the virtual reality headset HTC Vive and controllers. The set included tracking technology called Lighthouse, which utilized wall-mounted "base stations" for positional tracking using infrared light.

2015–present

By 2016 there were at least 230 companies developing VR-related products. Facebook has 400 employees focused on VR development; Google, Apple, Amazon, Microsoft, Sony and Samsung all had dedicated AR and VR groups. Dynamic binaural audio was common to most headsets released that year. However, haptic interfaces were not well developed, and most hardware packages incorporated button-operated handsets for touch-based interactivity. Visually, displays were still of a low-enough resolution and frame-rate that images were still identifiable as virtual. On April 5, 2016, HTC shipped its first units of the HTC VIVE SteamVR headset. This marked the first major commercial release of sensor-based tracking, allowing for free movement of users within a defined space.

In early 2017, a patent filed by Sony showed they were developing a similar location tracking technology to the VIVE for PlayStation VR, with the potential for the development of a wireless headset.

Applications

Main article: Applications of VR

File:VR-Helm.jpg

U.S. Navy personnel using a VR parachute training simulator.

VR has many applications in a variety of fields. It is most commonly used in entertainment applications such as gaming and 3D cinema. Consumer virtual reality headsets were first released by video game companies in the early-mid 1990's. Beginning in the 2010's, next-generation commercial tethered headsets were released by Oculus, the HTC Vive and PlayStation VR, setting off a new wave of application development.

3D cinema has been used for sporting events, pornography, fine art, music videos and short films. Since 2015, virtual reality has been installed onto a number of roller coasters and theme parks.

In robotics, virtual reality has been used to control robots in telepresence and telerobotic systems.

In social sciences and psychology, virtual reality offers a cost-effective tool to study and replicate interactions in a controlled environment.

File:Worldskin-01.jpg

"World Skin, A Photo Safari in the Land of War" - Maurice Benayoun, Jean-Baptiste Barrière, Virtual Reality Installation - 1997

Surgery training can be done through virtual reality. Other medical uses include virtual reality exposure therapy (VRET), a form of exposure therapy for treating anxiety disorders such as post traumatic stress disorder (PTSD) and phobias. In some cases, patients no longer meet the DSM-V criteria for PTSD after a series of treatments with VRET.

VR can simulate real spaces for workplace occupational safety and health purposes, educational purposes, and training purposes. It can be used to provide learners with a virtual environment where they can develop their skills without the real-world consequences of failing. It has been used and studied in primary education, military, astronaut training, flight simulators and driver training.

The first fine art virtual world was created in the 1970s. As the technology developed, more artistic programs were produced throughout the 1990s. When commercially available technology became more widespread, VR festivals began to emerge in the mid-2010s. The first uses of VR in museum settings began in the 1990s, seeing significant increase in the mid-2010s. Additionally museums have begun making some of their content virtual reality accessible. Immersive VR engineering systems enable engineers to see virtual prototypes prior to the availability of any physical prototypes.

Virtual reality's growing market presents an opportunity and an alternative channel for digital marketing.

In fiction and popular culture

Main article: Virtual reality in fiction

There have been many novels that reference and describe forms of virtual reality. Neal Stephenson's Snow Crash (1992) and Ernest Cline's Ready Player One (2011) are novels that have been influential for VR engineers working in the early 21st century.

In the 1980s and 1990s, Cyberpunks viewed the technology as a potential means for social change. The recreational drug subculture praised virtual reality not only as a new art form, but as an entirely new frontier.

Concerns and challenges

Virtual reality technology faces a number of challenges, including health and safety, privacy and technical issues. Long-term effects of virtual reality on vision and neurological development are unknown; users might become disoriented in a purely virtual environment, causing balance issues; computer latency might affect the simulation, providing a less-than-satisfactory end-user experience; navigating the non-virtual environment (if the user is not confined to a limited area) might prove dangerous without external sensory information. There have been rising concerns that with the advent of virtual reality, some users may experience virtual reality addiction. From an economic and financial perspective, early entrants to the virtual reality market may spend a significant amount of time and money on the technology. If it is not adopted by enough customers, the investment will not pay off.

Health and safety

There are many health and safety considerations of virtual reality. Most virtual reality systems come with consumer warnings, including: seizures; developmental issues in children; trip-and-fall and collision warnings; discomfort; repetitive stress injury; and interference with medical devices.

A number of unwanted symptoms have been caused by prolonged use of virtual reality, and these may have slowed proliferation of the technology. For example, in 1995, Nintendo released a gaming console known as the Virtual Boy. Worn as a headpiece and connected to a typical controller, the Virtual Boy received much criticism for its negative physical effects, including "dizziness, nausea, and headaches". Virtual reality sickness (also known as cybersickness) occurs when a person's exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms. The most common symptoms are general discomfort, headache, stomach awareness, nausea, vomiting, pallor, sweating, fatigue, drowsiness, disorientation, and apathy. Other symptoms include postural instability and retching. Virtual reality sickness is different from motion sickness in that it can be caused by the visually induced perception of self-motion; real self-motion is not needed. It is also different from simulator sickness; non-virtual reality simulator sickness tends to be characterized by oculomotor disturbances, whereas virtual reality sickness tends to be characterized by disorientation. A 2016 publication assessed the effects of exposure to 2D vs 3D dissection videos on nine pathology resident physicians, using self-reported physiologic symptoms. Watching the content in 3D vs 2D did not increase simulator sickness. Although the average simulator sickness questionnaire score did increase with time, statistical analysis does not suggest significance.

Privacy

The persistent tracking required by all VR systems makes the technology particularly useful for, and vulnerable to, mass surveillance. The expansion of VR will increase the potential and reduce the costs for information gathering of personal actions, movements and responses. In networked VR spaces with capacity for public interaction, there is the potential for unexpected modifications of the environment.

Conceptual and philosophical concerns

In addition, there are conceptual and philosophical considerations and implications associated with the use of virtual reality. What the phrase "virtual reality" means or refers to can be ambiguous. Mychilo S. Cline argued in 2005 that through virtual reality techniques will be developed to influence human behavior, interpersonal communication, and cognition. In the book The Metaphysics of Virtual Reality by Michael R. Heim, seven different concepts of virtual reality are identified: simulation, interaction, artificiality, immersion, telepresence, full-body immersion, and network communication. As we spend more and more time in virtual space, there could be a gradual "migration to virtual space", resulting in important changes in economics, worldview, and culture. Philosophical implications of VR are discussed in books, including Philip Zhai's Get Real: A Philosophical Adventure in Virtual Reality (1998) and Digital Sensations: Space, Identity and Embodiment in Virtual Reality (1999), written by Ken Hillis.

Pioneers and notables

• Thomas A. Furness III
• Maurice Benayoun
• Mark Bolas
• Fred Brooks
• Anshe Chung
• Edmond Couchot
• Carolina Cruz-Neira
• James H. Clark
• Doug Church
• Char Davies
• Tom DeFanti
• David Em
• Scott Fisher
• William Gibson
• Morton Heilig
• Eric Howlett
• Myron Krueger
• Knowbotic Research
• Jaron Lanier
• Brenda Laurel
• Palmer Luckey
• Jacquelyn Ford Morie
• Michael Naimark
• Randy Pausch
• Mark Pesce
• Warren Robinett
• Philip Rosedale
• Louis Rosenberg
• Dan Sandin
• Susumu Tachi
• Ivan Sutherland

Commercial industries

Further information: Comparison of retail head-mounted displays

The companies working in the virtual reality sector fall broadly into three categories of involvement: hardware (making headsets and input devices specific to VR), software (producing software for interfacing with the hardware or for delivering content to users) and content creation (producing content, whether interactive or passive storylines, games, and artificial worlds, for consumption and exploration with VR hardware).

HMD devices

• Facebook (Oculus Rift)
• Google (Google Cardboard, Google Daydream)
• HTC & Valve (HTC Vive)
• Microsoft (Microsoft HoloLens, Windows Mixed Reality)
• Razer (OSVR Hacker Dev Kit)
• Samsung (Samsung Gear VR)
• Sony Computer Entertainment (PS VR)
• Starbreeze Studios (StarVR)
• Lenovo Explorer

Input devices

• Cyberith Virtualizer
• Leap Motion
• Nokia (Nokia OZO camera)
• Sixense
• uSens
• Virtuix Omni
• ZSpace (company)

Software

• VREAM
• vorpX

Content

• Framestore
• iClone
• Innervision
• Moving Picture Company
• Reel FX
• xRes

Emerging technologies

• 360 degree video
• Augmented reality
• HoloLens
• Intel RealSense
• Magic Leap
• Mixed reality
• Haptic technology

Companies

• Google
• Facebook
• Apple
• HTC
• Valve
• Samsung
• Microsoft
• Intel
• Campustours
• Sketchfab
• Sony
• Lenovo

Artists

• Rebecca Allen
• Maurice Benayoun
• Sheldon Brown
• Char Davies
• David Em
• Myron Krueger
• Jaron Lanier
• Jacquelyn Ford Morie
• Brenda Laurel
• Michael Naimark
• Jeffrey Shaw
• Nicole Stenger
• Tamiko Thiel

See also

• 16K resolution
• AlloSphere
• Computer-mediated reality
• Diorama
• Extended reality
• Holographic universe
• Methods of virtual reality
• Mixed reality
• Reality–virtuality continuum
• Virtual body
• Virtual globe
• Virtual machining
• Virtual taste
• WebVR

References

General references

• Choi, SangSu, Kiwook Jung, and Sang Do Noh. "Virtual reality applications in manufacturing industries: Past research, present findings, and future directions." Concurrent Engineering (2015): 1063293X14568814.

Inline citations

• Kulkarni, S.D.; Minor, M.A.; Deaver, M.W.; Pardyjak, E.R.; Hollerbach, J.M.Design, Sensing, and Control of a Scaled Wind Tunnel for Atmospheric Display, Mechatronics, IEEE/ASME Transactions on, vol.17, no.4, pp. 635–645, Aug. 2012
• Blascovich, J Bailenson, J. Infinite Reality: Avatars, Eternal Life, New Worlds, and the Dawn of the Virtual Revolution, Harper Collins, 2011.
• TechCast Article Series, Mateo Fernandez, Metaverse
• TechCast Article Series, Aaron Druck, When will Virtual Reality become reality?
• Brooks Jr, F. P. (1999). "What's Real About Virtual Reality?". IEEE Computer Graphics and Applications 19 (6): 16. doi:10.1109/38.799723. http://www.cs.unc.edu/~brooks/WhatsReal.pdf. 
• Burdea, G. and P. Coffet (2003). Virtual Reality Technology, Second Edition. Wiley-IEEE Press.
• Genovese, Paolo Vincenzo (2005). Dalla Decostruzione alla Cyber-Architettura e oltre. L'uso del computer nella progettazione degli spazi non-euclidei. Liguori Editore, Napoli. In Italian.
• Goslin, M; Morie, J. F. (1996). "Virtopia" Emotional experiences in Virtual Environments". Leonardo 29 (2): 95–100. doi:10.2307/1576338. 
• Oliver Grau, (2003) Virtual Art: From Illusion to Immersion (Leonardo Book Series). Cambridge/Massachusetts: MIT-Press.
• 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).
• Hillis, Ken (1999). Digital Sensations: Space, Identity and Embodiment in Virtual Reality. University of Minnesota Press, Minneapolis, Minnesota.
• 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, Massachusetts
• 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)
• 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.
• Krueger, Myron (1991). Artificial Reality II, Addison-Wesley, Reading, Massachusetts
• Lanier, Jaron; Biocca, F. (1992). "An Insider's View of the Future of Virtual Reality". Journal of Communication 42 (4): 150. doi:10.1111/j.1460-2466.1992.tb00816.x. 
• 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.
• Joseph Nechvatal, Immersive Ideals / Critical Distances. LAP Lambert Academic Publishing. 2009
• Rheingold, Howard (1992). Virtual Reality, Simon & Schuster, New York, N.Y.
• Robinett, Warren (1994). "Interactivity and Individual Viewpoint in Shared Virtual worlds: The Big Screen vs. Networked Personal Displays". Computer Graphics 28 (2): 127. doi:10.1145/178951.178969. 
• 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).
• Roudavski, S. (2010). Virtual Environments as Techno-Social Performances: Virtual West Cambridge Case-Study, in CAADRIA2010: New Frontiers, the 15th International Conference on Computer Aided Architectural Design Research in Asia, ed. by Bharat Dave, Andrew I-kang Li, Ning Gu and Hyoung-June Park, pp. 477–486
• Mel Slater and Martin Usoh (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, Ivan (1965). "The Ultimate Display" (PDF). Proceedings of IFIP 65 2: 506–508. http://www.informatik.umu.se/~jwworth/The%20Ultimate%20Display.pdf. 
• Warwick, K., Gray, J. and Roberts, D. eds. (1993). Virtual Reality in Engineering, Peter Peregrinus.
• Zhai, Philip. (1998). Get Real: A Philosophical adventure in Virtual Reality, Rowman & Littlefield Publishers, New York and Oxford.

External links

External video

Virtual Reality, Computer Chronicles (1992)

• Isaac, Joseph (2016). "Step into a new world - Virtual Reality (VR)". Retrieved 2 July 2016. {{cite web}}: Basic Concepts of Virtual Reality along with Research Challenges explained in simple words.
• Mixed Reality Scale – Milgram and Kishino's (1994) Virtuality Continuum paraphrase with examples.
• Drummond, Katie (2014). "The Rise and Fall and Rise of Virtual Reality". The Verge. Retrieved 15 November 2014. {{cite web}}: Interviews on the history and future of virtual reality by leaders in the field.
• "New Trends In Virtual Reality". {{cite web}}:
• "Virtual reality in human-system interaction". {{cite web}}:

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