Virtual reality (VR) is an interactive computer-generated experience taking place within a simulated environment. It incorporates mainly auditory and visual feedback, but may also allow other types of sensory feedback like haptic. This immersive environment can be similar to the real world or it can be fantastical. 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 giving the user the ability to view three-dimensional images.
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 video gaming and training applications.
Etymology and terminology
"Virtual" has had the meaning of "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, the French avant-garde playwright 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.
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).
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 360 interactive photography, although at low-resolutions or in highly compressed formats for online streaming of 360 video. In contrast, photogrammetry is increasingly used to combine several high-resolution photographs for the creation of detailed 3D objects and environments in VR applications.
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. The development of perspective in Renaissance Europe created convincing depictions of spaces that did not exist, in what has been referred to as the "multiplying of artificial worlds". Other elements of virtual reality appeared as early as the 1860s. 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.
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".
The VR industry mainly provided VR devices for medical, flight simulation, automobile industry design, and military training purposes from 1970 to 1990.
The Aspen Movie Map was created at the 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.
In 1979 Eric Howlett developed the Large Expanse, Extra Perspective (LEEP) optical system. The combined system created a stereoscopic image with a field of view wide enough to create a convincing sense of space. The users of the system have been impressed by the sensation of depth [field of view] in the scene and the corresponding realism. The original LEEP system was redesigned for the NASA Ames Research Center in 1985 for their first virtual reality installation, the VIEW (Virtual Interactive Environment Workstation) by Scott Fisher. The LEEP system provides the basis for most of the current virtual reality helmets available today.
Atari founded a research lab for virtual reality in 1982, but the lab was closed after two years due to the Atari Shock (North American video game crash of 1983). However, its hired employees, such as Tom Zimmerman, Scott Fisher, Jaron Lanier, Michael Naimark, 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 EyePhone, 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.
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, 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.
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.
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. 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. Apple released QuickTime VR, which, despite using the term "VR", was unable to represent virtual reality, and instead displayed 360 photographic panoramas.
Nintendo's Virtual Boy console was released in 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. Forte released the VFX1, a PC-powered virtual reality headset in 1995.
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.
In 2001, SAS Cube (SAS3) became the first PC based cubic room, developed by Z-A Production (Maurice Benayoun, David Nahon), Barco, and Clarté. It was installed in Laval, France. 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, Miguel Schiaffino Tienda announced vrAse, a headset that used the smartphone for doing both virtual and augmented reality.
In 2013, Valve Corporation discovered and freely shared the breakthrough of low-persistence displays which made 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.
2014, Facebook purchased Oculus VR for $2 billion. This purchase occurred after the first development kits ordered through Oculus' 2012 Kickstarter had shipped in 2013 but before the shipping of their second development kits in 2014.
In 2014, Sony announced Project Morpheus (its code name for PlayStation VR), a virtual reality headset for the PlayStation 4 video game console. In 2015, HTC and Valve 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.
In 2015, Google announced Cardboard, a do-it-yourself stereoscopic viewer for smartphones. The user places their smartphone in the cardboard holder, which they wear on their head. Michael Naimark was appointed Google's first-ever 'resident artist' in their new VR division. The Kickstarter campaign for Gloveone, a pair of gloves providing motion tracking and haptic feedback, was successfully funded, with over $150,000 in contributions.
By 2016 there were at least 230 companies developing VR-related products. Facebook had 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.
In 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 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.
VR 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 1990s. Beginning in the 2010s, next-generation commercial tethered headsets were released by Oculus (Rift), HTC (Vive) and Sony (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, roller coasters and theme parks have incorporated virtual reality to match visual effects with haptic feedback .
In robotics, virtual reality has been used to control robots in telepresence and telerobotic systems. It has been used in robotics development. For example, in experiments that investigate how robots—through virtual articulations—can be applied as an intuitive human user interface. Another example is the use of robots that are remotely controlled in dangerous environments such as space. Here, virtual reality not only offers insights into the manipulation and locomotion of robotic technology but also shows opportunities for inspection.
In social sciences and psychology, virtual reality offers a cost-effective tool to study and replicate interactions in a controlled environment. It can be used as a form of therapeutic intervention. For instance, there is the case of the virtual reality exposure therapy (VRET), a form of exposure therapy for treating anxiety disorders such as post traumatic stress disorder (PTSD) and phobias.
In medicine, simulated VR surgical environments - under the supervision of experts - can provide effective and repeatable training at a low cost, allowing trainees to recognize and amend errors as they occur.
Virtual reality has been used in rehabilitation since the 2000s. Despite numerous studies conducted, good quality evidence of its efficacy compared to other rehabilitation methods without sophisticated and expensive equipment is lacking for the treatment of Parkinson's disease. A 2018 review on the effectiveness of mirror therapy by virtual reality and robotics for any type of pathology concluded in a similar way. Another study was conducted that showed the potential for VR to promote mimicry and revealed the difference between neurotypical and autism spectrum disorder individuals in their response to a two-dimensional avatar.
VR can simulate real workspaces 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, miner training, driver training and bridge inspection. Immersive VR engineering systems enable engineers to see virtual prototypes prior to the availability of any physical prototypes. Supplementing training with virtual training environments has been claimed to offer avenues of realism in military and healthcare training while minimizing cost. It also has been claimed to reduce military training costs by minimizing the amounts of ammunition expended during training periods.
The first fine art virtual world was created in the 1970s. As the technology developed, more artistic programs were produced throughout the 1990s, including feature films. 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 a significant increase in the mid-2010s. Additionally, museums have begun making some of their content virtual reality accessible.
Virtual reality's growing market presents an opportunity and an alternative channel for digital marketing. It is also seen as a new platform for e-commerce, particularly in the bid to challenge traditional brick and mortar retailers. However, a 2018 study revealed that the majority of goods are still purchased in physical stores.
Concerns and challenges
Health and safety
There are many health and safety considerations of virtual reality. A number of unwanted symptoms have been caused by prolonged use of virtual reality, and these may have slowed proliferation of the technology. 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. Some users may experience twitches, seizures or blackouts while using VR headsets, even if they do not have a history of epilepsy and have never had blackouts or seizures before. As many as one in 4000 people may experience these symptoms. Since these symptoms are more common among people under the age of 20, children are advised against using VR headsets. Other problems may occur in physical interactions with one's environment. While wearing VR headsets, people quickly lose awareness of their real-world surroundings and may injure themselves by tripping over, or colliding with real-world objects.
VR headsets may regularly cause eye fatigue, as does all screened technology, because people tend to blink less when watching screens, causing their eyes to become more dried out. There have been some concerns about VR headsets contributing to myopia, but although VR headsets sit close to the eyes, they may not necessarily contribute to nearsightedness if the focal length of the image being displayed is sufficiently far away.
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. 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". These motion sickness symptoms are caused by a disconnect between what is being seen and what the rest of the body perceives. When the vestibular system, the body's internal balancing system, does not experience the motion that it expects from visual input through the eyes, the user may experience VR sickness. This can also happen if the VR system does not have a high enough frame rate, or if there is a lag between the body's movement and the onscreen visual reaction to it. Because approximately 25–40% of people experience some kind of VR sickness when using VR machines, companies are actively looking for ways to reduce VR sickness.
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.
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.
- 16K resolution
- Brain-computer interface
- Computer-mediated reality
- Extended reality
- First-person perspective
- Holographic universe
- Methods of virtual reality
- Mixed reality
- Reality–virtuality continuum
- Virtual body
- Virtual globe
- Virtual machining
- Virtual reality headset
- Virtual taste
- Virtual tour
- Applications of VR
- "Online Etymology Dictionary".
- Antonin Artaud, The Theatre and its Double Trans. Mary Caroline Richards. (New York: Grove Weidenfeld, 1958).
- "the definition of cyberspace".
- Myron Krueger. Artificial Reality 2, Addison-Wesley Professional, 1991. ISBN 0-201-52260-8
- "VRML Virtual Reality Modeling Language". www.w3.org. Retrieved 20 March 2017.
- Brutzman, Don (October 2016). "X3D Graphics and VR" (PDF). web3D.org. Web3D Consortium. Retrieved 20 March 2017.
- kelly, kevin (April 2016). "The Untold Story of Magic Leap, the World's Most Secretive Startup". WIRED. Retrieved 13 March 2017.
- Orellana, Vanessa Hand (31 May 2016). "10 things I wish I knew before shooting 360 video". CNET. Retrieved 20 March 2017.
- "Resident Evil 7: The Use of Photogrammetry for VR". 80.lv. Retrieved 20 March 2017.
- Johnson, Leif (13 March 2016). "Forget 360 Videos, Photogrammetric Virtual Reality Is Where It's At - Motherboard". Motherboard. Retrieved 20 March 2017.
- Matthew Schnipper. "Seeing is Believing: The State of Virtual Reality". The Verge. Retrieved 7 March 2017.
- Baltrušaitis, Jurgis; Strachan, W.J. (1977). Anamorphic art. New York: Harry N. Abrams. p. 4. ISBN 9780810906624.
- "How did virtual reality begin?". Virtual Reality Society. Retrieved 7 March 2017.
- Holly Brockwell (3 April 2016). "Forgotten genius: the man who made a working VR machine in 1957". Tech Radar. Retrieved 7 March 2017.
- "National Center for Supercomputing Applications: History". The Board of Trustees of the University of Illinois. Archived from the original on 21 August 2015.
- Nelson, Ted (March 1982). "Report on Siggraph '81". Creative Computing.
- Thomas, Wayne (December 2005). "Virtual Reality and Artificial Environments", A Critical History of Computer Graphics and Animation. Section 17.
- Goad, Angela. "Carolina Cruz-Neira | Introductions Necessary". Introductions Necessary. Retrieved 28 March 2017.
- Smith, David (November 24, 2014). "Engineer envisions sci-fi as reality". Arkansas Online. Retrieved 28 March 2017.
- Rosenberg, Louis (1992). "The Use of Virtual Fixtures As Perceptual Overlays to Enhance Operator Performance in Remote Environments.". Technical Report AL-TR-0089, USAF Armstrong Laboratory, Wright-Patterson AFB OH, 1992.
- Rosenberg, L.B. (1993). "Virtual Fixtures: Perceptual Overlays for Telerobotic Manipulation". In Proc. of the IEEE Annual Int. Symposium on Virtual Reality (1993): pp. 76–82.
- Gonzales, D. (editor) (1991). "Automation and Robotics for the Space Exploration Initiative: Results from Project Outreach" (PDF). 92 (17897): 35.CS1 maint: Extra text: authors list (link)
- Horowitz, Ken (December 28, 2004). "Sega VR: Great Idea or Wishful Thinking?". Sega-16. Archived from the original on 2010-01-14. Retrieved 21 August 2010.
- "Virtuality". YouTube. Retrieved 21 September 2014.
- Engler, Craig E. (November 1992). "Affordable VR by 1994". Computer Gaming World. p. 80. Retrieved 4 July 2014.
- "Arcade Heroes Sega's Wonderful Simulation Games Over The Years – Arcade Heroes". Arcade Heroes. Retrieved 20 October 2015.
- "System 16 – Sega Medium Scale Attractions Hardware (Sega)". system16.com. Retrieved 20 October 2015.
- "NEXT Generation Issue #6 June 1995". archive.org. Retrieved 20 October 2015.
- "Nintendo Virtual Boy on theverge.com".
- "Virtual Reality Applications Expand : Imaging: Technology is finding important places in medicine, engineering and many other realms – LA Times".
- Au, Wagner James. The Making of Second Life, pg. 19. New York: Collins. ISBN 978-0-06-135320-8.
- "Google Street View in 3D: More Than Just an April Fool's Joke".
- Rubin, Peter. (2014). Oculus Rift. Wired, 22(6), 78.
- "[Saturday Ridiculousness] vrAse Is The Perfect Solution To A Problem Nobody Has". Android Police. 2013-08-31. Retrieved 2018-12-25.
- "Not-quite-live bloga : panel discussion with John Carmack, Tim Sweeney, Johan Andersson". The Tech Report. Retrieved 2016-12-14.
- James, Paul (2014-01-30). "30 Minutes Inside Valve's Prototype Virtual Reality Headset: Owlchemy Labs Share Their Steam Dev Days Experience - Road to VR". Road to VR. Retrieved 2016-12-14.
- James, Paul (2013-11-18). "Valve to Demonstrate Prototype VR HMD and Talk Changes to Steam to "Support and Promote VR Games" - Road to VR". Road to VR. Retrieved 2016-12-14.
- "Facebook to buy Oculus virtual reality firm for $2B". Associated Press. March 25, 2014. Retrieved March 27, 2014.
- Metz, Cade. "Facebook Buys VR Startup Oculus for $2 Billion". WIRED. Retrieved 13 March 2017.
- "Sony Announces 'Project Morpheus:' Virtual Reality Headset For PS4".
- "Valve showing off new virtual reality hardware and updated Steam controller next week". The Verge. Retrieved 1 March 2015.
- "Valve's VR headset revealed with Oculus-like features". The Verge. Retrieved 1 March 2015.
- "HTC Vive: Everything you need to know about the SteamVR headset". Wareable. Retrieved 2016-06-19.
- "Gloveone: Feel Virtual Reality". Kickstarter. Retrieved 2016-05-15.
- "Vive Shipment Updates - VIVE Blog". VIVE Blog. 2016-04-07. Retrieved 2016-06-19.
- Prasuethsut, Lily (August 2, 2016). "HTC Vive: Everything you need to know about the SteamVR headset". Wareable. Retrieved 13 March 2017.
- Martindale, Jon (15 February 2017). "Vive-like sensor spotted in new Sony patent could make its way to PlayStation VR". Digital Trends. Retrieved 13 March 2017.
- "Comparison of VR headsets: Project Morpheus vs. Oculus Rift vs. HTC Vive". Data Reality. Archived from the original on 20 August 2015. Retrieved 15 August 2015.
- Rosenberg, L., "Virtual fixtures as tools to enhance operator performance in telepresence environments," SPIE Manipulator Technology, 1993.
- Gulrez, Tauseef; Hassanien, Aboul Ella (2012). Advances in Robotics and Virtual Reality. Berlin: Springer-Verlag. p. 275. ISBN 9783642233623.
- Groom, Victoria; Bailenson, Jeremy N.; Nass, Clifford (2009-07-01). "The influence of racial embodiment on racial bias in immersive virtual environments". Social Influence. 4 (3): 231–248. doi:10.1080/15534510802643750. ISSN 1553-4510.
- Gonçalves, Raquel; Pedrozo, Ana Lúcia; Coutinho, Evandro Silva Freire; Figueira, Ivan; Ventura, Paula (2012-12-27). "Efficacy of Virtual Reality Exposure Therapy in the Treatment of PTSD: A Systematic Review". PLOS ONE. 7 (12): e48469. doi:10.1371/journal.pone.0048469. ISSN 1932-6203. PMC 3531396. PMID 23300515.
- Garrick, Jacqueline; Williams, Mary Beth (2014). Trauma Treatment Techniques: Innovative Trends. London: Routledge. p. 199. ISBN 9781317954934.
- Westwood, J.D. Medicine Meets Virtual Reality 21: NextMed / MMVR21. IOS Press. p. 462.
- Dockx, Kim (2016). "=Virtual reality for rehabilitation in Parkinson's disease". Cochrane Database of Systematic Reviews. 12: CD010760. doi:10.1002/14651858.CD010760.pub2. PMID 28000926.
- Darbois, Nelly; Guillaud, Albin; Pinsault, Nicolas (2018). "Does Robotics and Virtual Reality Add Real Progress to Mirror Therapy Rehabilitation? A Scoping Review". Rehabilitation Research and Practice. 2018: 1–15. doi:10.1155/2018/6412318.
- Forbes, Paul A. G.; Pan, Xueni; Hamilton, Antonia F. de C. "Reduced Mimicry to Virtual Reality Avatars in Autism Spectrum Disorder". Journal of Autism and Developmental Disorders. doi:10.1007/s10803-016-2930-2#citeas.
- "Online High School In Japan Enters Virtual Reality". blogs.wsj.com.
- "DSTS: First immersive virtual training system fielded". www.army.mil. Retrieved 2017-03-16.
- "Virtual reality used to train Soldiers in new training simulator".
- "NASA shows the world its 20-year virtual reality experiment to train astronauts: The inside story – TechRepublic". TechRepublic. Retrieved 2017-03-15.
- James, Paul (2016-04-19). "A Look at NASA's Hybrid Reality Astronaut Training System, Powered by HTC Vive – Road to VR". Road to VR. Retrieved 2017-03-15.
- "How NASA is Using Virtual and Augmented Reality to Train Astronauts". Unimersiv. 2016-04-11. Retrieved 2017-03-15.
- Dourado, Antônio O.; Martin, C.A. (2013). "New concept of dynamic flight simulator, Part I". Aerospace Science and Technology. 30 (1): 79–82. doi:10.1016/j.ast.2013.07.005.
- "Virtual Reality in Mine Training". www.cdc.gov. Retrieved 2018-11-09.
- "How Virtual Reality Military Applications Work".
- Omer; et al. (2018). "Performance evaluation of bridges using virtual reality". Proceedings of the 6th European Conference on Computational Mechanics (ECCM 6) & 7th European Conference on Computational Fluid Dynamics (ECFD 7), Glasgow, Scotland.
- Seu; et al. (2018). "Use of gaming and affordable VR technology for the visualization of complex flow fields". Proceedings of the 6th European Conference on Computational Mechanics (ECCM 6) & 7th European Conference on Computational Fluid Dynamics (ECFD 7), Glasgow, Scotland.
- Shufelt, Jr., J.W. (2006) A Vision for Future Virtual Training. In Virtual Media for Military Applications (pp. KN2-1 – KN2-12). Meeting Proceedings RTO-MP-HFM-136, Keynote 2. Neuilly-sur-Seine, France: RTO. Available from: http://www.rto.nato.int/abstracts.asp
- Bukhari, Hatim; Andreatta, Pamela; Goldiez, Brian; Rabelo, Luis (2017-01-01). "A Framework for Determining the Return on Investment of Simulation-Based Training in Health Care". INQUIRY: The Journal of Health Care Organization, Provision, and Financing. 54: 0046958016687176. doi:10.1177/0046958016687176. ISSN 0046-9580. PMC 5798742. PMID 28133988.
- Smith, Roger (2010-02-01). "The Long History of Gaming in Military Training". Simulation & Gaming. 41 (1): 6–19. doi:10.1177/1046878109334330. ISSN 1046-8781.
- Mura, Gianluca (2011). Metaplasticity in Virtual Worlds: Aesthetics and Semantic Concepts. Hershey, PA: Information Science Reference. p. 203. ISBN 978-1-60960-077-8.
- "Virtual reality at the British Museum: What is the value of virtual reality environments for learning by children and young people, schools, and families? – MW2016: Museums and the Web 2016".
- "Extending the Museum Experience with Virtual Reality". 18 March 2016.
- Shirer, Michael; Torchia, Marcus (February 27, 2017). "Worldwide Spending on Augmented and Virtual Reality Forecast to Reach $13.9 Billion in 2017, According to IDC". International Data Corporation. International Data Corporation. Retrieved March 16, 2018.
- "How Technology is Expanding the Scope of Online Commerce Beyond Retail". www.walkersands.com. Retrieved 2018-08-31.
- Lawson, B. D. (2014). Motion sickness symptomatology and origins. Handbook of Virtual Environments: Design, Implementation, and Applications, 531-599.
- "Oculus Rift Health and Safety Notice" (PDF). Retrieved 13 March 2017.
- Fagan, Kaylee. "Here's what happens to your body when you've been in virtual reality for too long". Business Insider. Retrieved 5 September 2018.
- Mukamal, Reena. "Are Virtual Reality Headsets Safe for Eyes?". American Academy of Ophthalmology. Retrieved 11 September 2018.
- Langley, Hugh. "We need to look more carefully into the long-term effects of VR". Wareable.com. Retrieved 11 September 2018.
- Kiryu, T; So, RH (25 September 2007). "Sensation of presence and cybersickness in applications of virtual reality for advanced rehabilitation". Journal of Neuroengineering and Rehabilitation. 4: 34. doi:10.1186/1743-0003-4-34. PMC 2117018. PMID 17894857.
- Hicks, Jamison S.; Durbin, David B. (June 2011). "ARL-TR-5573: A Summary of Simulator Sickness Ratings for U.S. Army Aviation Engineering Simulators" (PDF). US Army Research Laboratory.
- Frischling, Bill. "Sideline Play." The Washington Post (1974-Current file): 11. ProQuest Historical Newspapers: The Washington Post (1877-1995). October 25, 1995. Web. May 24, 2012.
- Caddy, Becca. "Vomit Reality: Why VR makes some of us feel sick and how to make it stop". Wareable.com. Retrieved 11 September 2018.
- Samit, Jay. "A Possible Cure for Virtual Reality Motion Sickness". Fortune.com. Retrieved 11 September 2018.
- Cline, Mychilo Stephenson (2005). Power, Madness, & Immortality: the Future of Virtual Reality. Virtualreality.universityvillagepress.com. Retrieved 2009-10-28.
- "The Future of Virtual Reality with Mychilo Cline " Introduction to the Future of Virtual Reality". Virtualreality.universityvillagepress.com. Retrieved 2009-10-28.
- "Power, Madness and Immortality | KurzweilAI". www.kurzweilai.net. Retrieved 28 March 2017.
- 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.
|Wikimedia Commons has media related to Virtual reality.|
|Virtual Reality, Computer Chronicles (1992)|
- Isaac, Joseph (2016). "Step into a new world - Virtual Reality (VR)". Retrieved 2 July 2016. 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. Interviews on the history and future of virtual reality by leaders in the field.
- "Virtual reality in human-system interaction".