HomeTECHNOLOGYWhat Is Virtual Reality? | Definition and Examples

What Is Virtual Reality? | Definition and Examples

What Is Virtual Reality? | Definition and Examples
Picture by Wade Sisler courtesy of NASA Ames Research Center.

You will never go to Mars, swim with dolphins, run an Olympic 100 meters, or sing onstage with the Rolling Stones. But in virtual reality, you will able to do all these things and many more without even leaving your home. Unlike original reality (the actual world in which we live), virtual reality means simulating bits of our world (or completely imaginary worlds) using high-performance computers and sensory equipment, like headsets and gloves. Apart from games and entertainment, it’s long been used for training airline pilots and surgeons and for helping scientists to figure out complex problems such as the structure of protein molecules. What Is Virtual Reality? Let’s take a closer look!

What is Virtual Reality?

The definition of virtual reality comes, naturally, from the definitions for both ‘virtual’ and ‘reality’. The definition of ‘virtual’ is near and reality is what we experience as human beings. So the term ‘virtual reality’ basically means ‘near-reality’. This could, of course, mean anything but it usually refers to a specific type of reality emulation.

We know the world through our senses and perception systems. In school, we all learned that we have five senses: taste, touch, smell, sight, and hearing. These are however only our most obvious sense organs. The truth is that humans have many more senses than this, such as a sense of balance for example. These other sensory inputs, plus some special processing of sensory information by our brains ensures that we have a rich flow of information from the environment to our minds.

Everything that we know about our reality comes by way of our senses. In other words, our entire experience of reality is simply a combination of sensory information and our brain’s sense-making mechanisms for that information. It stands to reason then, that if you can present your senses with made-up information, your perception of reality would also change in response to it. You would be presented with a version of reality that isn’t there, but from your perspective, it would be perceived as real. Something we would refer to as a virtual reality.

So, in summary, virtual reality entails presenting our senses with a computer-generated virtual environment that we can explore in some fashion.

Putting it another way, virtual reality is essential:

  1. Believable: You need to feel like you’re in your virtual world (on Mars, or wherever) and to keep believing that, or the illusion of virtual reality will disappear.
  2. Interactive: As you move around, the VR world needs to move with you. You can watch a 3D movie and be transported up to the Moon or down to the seabed—but it’s not interactive in any sense.
  3. Computer-generated: Why is that important? Because only powerful machines, with realistic 3D computer graphics, are fast enough to make believable, interactive, alternative worlds that change in real-time as we move around them.
  4. Explorable: A VR world needs to be big and detailed enough for you to explore. However realistic painting is, it shows only one scene, from one perspective. A book can describe a vast and complex “virtual world,” but you can only really explore it linearly, exactly as the author describes it.
  5. Immersive: To be both believable and interactive, VR needs to engage both your body and your mind. Paintings by war artists can give us glimpses of conflict, but they can never fully convey the sight, sound, smell, taste, and feel of a battle. You can play a flight simulator game on your home PC and be lost in a very realistic, interactive experience for hours (the landscape will constantly change as your plane flies through it), but it’s not like using a real flight simulator (where you sit in a hydraulically operated mockup of a real cockpit and feel actual forces as it tips and tilts), and even less like flying a plane.

We can see from this why reading a book, looking at a painting, listening to a classical symphony, or watching a movie doesn’t qualify as virtual reality. All of them offer partial glimpses of another reality, but none are interactive, explorable, or fully believable. If you’re sitting in a movie theater looking at a giant picture of Mars on the screen, and you suddenly turn your head too far, you’ll see and remember that you’re actually on Earth and the illusion will disappear. If you see something interesting on the screen, you can’t reach out and touch it or walk towards it; again, the illusion will simply disappear. So these forms of entertainment are essentially passive: however plausible they might be, they don’t actively engage you in any way.

VR is quite different. It makes you think you are living inside a completely believable virtual world (one in which, to use the technical jargon, you are partly or fully immersed). It is two-way interactive: as you respond to what you see, what you see responds to you: if you turn your head around, what you see or hear in VR changes to match your new perspective.

What Is Virtual Reality – In Technical Terms…

Answering “what is virtual reality” in technical terms is straight-forward. Virtual reality is the term used to describe a three-dimensional, computer-generated environment that can be explored and interacted with by a person. That person becomes part of this virtual world or is immersed within this environment and whilst there, he can manipulate objects or perform a series of actions.

Types of Virtual Reality

“Virtual reality” has often been used as a marketing buzzword for compelling, interactive video games or even 3D movies and television programs, none of which count as VR because they don’t immerse you either fully or partially in a virtual world. Search for “virtual reality” in your cellphone app store and you’ll find hundreds of hits, even though a tiny cellphone screen could never get anywhere near producing the convincing experience of VR. Nevertheless, things like interactive games and computer simulations would certainly meet parts of our definition up above, so there’s more than one approach to building virtual worlds—and more than one flavor of virtual reality. Here are a few of the bigger variations:

Fully Immersive

For the complete VR experience, we need three things. First, a plausible, and richly detailed virtual world to explore; a computer model or simulation, in other words. Second, a powerful computer that can detect what we’re going and adjust our experience accordingly, in real-time (so what we see or hear changes as fast as we move—just like in real reality). Third, hardware linked to the computer that fully immerses us in the virtual world as we roam around. Usually, we’d need to put on what’s called a head-mounted display (HMD) with two screens and stereo sound, and wear one or more sensory gloves. Alternatively, we could move around inside a room, fitted out with surround-sound loudspeakers, onto which changing images are projected from outside. We’ll explore VR equipment in more detail in a moment.

Non-immersive

A highly realistic flight simulator on a home PC might qualify as non-immersive virtual reality, especially if it uses a very widescreen, with headphones or surround sound, and a real joystick and other controls. Not everyone wants or needs to be fully immersed in an alternative reality. An architect might build a detailed 3D model of a new building to show to clients that can be explored on a desktop computer by moving a mouse. Most people would classify that as a kind of virtual reality, even if it doesn’t fully immerse you. In the same way, computer archaeologists often create engaging 3D reconstructions of long-lost settlements that you can move around and explore. They don’t take you back hundreds or thousands of years or create the sounds, smells, and tastes of prehistory, but they give a much richer experience than a few pastel drawings or even an animated movie.

Collaborative

What about “virtual world” games like Second Life and Minecraft? Do they count as virtual reality? Although they meet the first four of our criteria (believable, interactive, computer-created and explorable), they don’t meet the fifth: they don’t fully immerse you. But one thing they do offer that cutting-edge VR typically doesn’t is collaboration: the idea of sharing an experience in a virtual world with other people, often in real-time or something very close to it. Collaboration and sharing are likely to become increasingly important features of VR in the future.

Web-based

Virtual reality was one of the hottest, fastest-growing technologies in the late 1980s and early 1990s, but the rapid rise of the World Wide Web largely killed off interest after that. Even though computer scientists developed a way of building virtual worlds on the Web (using a technology analogous to HTML called Virtual Reality Markup Language, VRML), ordinary people were much more interested in the way the Web gave them new ways to access real reality—new ways to find and publish information, shop, and share thoughts, ideas, and experiences with friends through social media. With Facebook’s growing interest in technology, the future of VR seems likely to be both Web-based and collaborative.

Augmented Reality

pilot heads up display
Photo: Augmented reality: A heads-up display, like this one used by the US Air Force, superimposes useful, computer-based information on top of the things you see with your own eyes. Picture by Major Chad E. Gibson courtesy of US Air Force.

Mobile devices like smartphones and tablets have put what used to be supercomputer power in our hands and pockets. If we’re wandering around the world, maybe visiting a heritage site like the pyramids or a fascinating foreign city we’ve never been to before, what we want is typically not virtual reality but an enhanced experience of the exciting reality we can see in front of us. That’s spawned the idea of augmented reality (AR), where, for example, you point your smartphone at a landmark or a striking building and interesting information about it pops up automatically. Augmented reality is all about connecting the real world we experience to the vast virtual world of information that we’ve collectively created on the Web. Neither of these worlds is virtual, but the idea of exploring and navigating the two simultaneously does, nevertheless, have things in common with virtual reality. For example, how can a mobile device figure out its precise location in the world? How do the things you see on the screen of your tablet change as you wander around a city? Technically, these problems are similar to the ones developers of VR systems have to solve—so there are close links between AR and VR.

What Equipment Do We Need For Virtual Reality?

Close your eyes and think of virtual reality and you probably picture something like our top photo: a geek wearing a wraparound headset (HMD) and datagloves, wired into a powerful workstation or supercomputer. What differentiates VR from an ordinary computer experience (using your PC to write an essay or play games) is the nature of the input and output. Where an ordinary computer uses things like a keyboard, mouse, or (more exotically) speech recognition for input, VR uses sensors that detect how your body is moving. And where a PC displays output on a screen (or a printer), VR uses two screens (one for each eye), stereo or surround-sound speakers, and maybe some forms of haptic (touch and body perception) feedback as well. Let’s take a quick tour through some of the more common VR input and output devices.

Head-mounted Displays (HMDs)

What Is Virtual Reality? | Definition and ExamplesThere are two big differences between VR and looking at an ordinary computer screen: in VR, you see a 3D image that changes smoothly, in real-time, as you move your head. That’s made possible by wearing a head-mounted display, which looks like a giant motorbike helmet or welding visor, but consists of two small screens (one in front of each eye), a blackout blindfold that blocks out all other light (eliminating distractions from the real world), and stereo headphones. The two screens display slightly different, stereoscopic images, creating a realistic 3D perspective of the virtual world. HMDs usually also have built-in accelerometers or position sensors so they can detect exactly how your head and body are moving (both position and orientation—which way they’re tilting or pointing) and adjust the picture accordingly. The trouble with HMDs is that they’re quite heavy, so they can be tiring to wear for long periods; some of them really heavy ones are even mounted on stands with counterweights. But HMDs don’t have to be so elaborate and sophisticated: at the opposite end of the spectrum, Google has developed an affordable, low-cost pair of cardboard goggles with built-in lenses that convert an ordinary smartphone into a crude HMD.

Immersive Rooms

An alternative to putting on an HMD is to sit or stand inside a room onto whose walls changing images are projected from outside. As you move into the room, the images change accordingly. Flight simulators use this technique, often with images of landscapes, cities, and airport approaches projected onto large screens positioned just outside a mockup of a cockpit. A famous 1990s VR experiment called CAVE (Cave Automatic Virtual Environment), developed at the University of Illinois by Thomas de Fanti, also worked this way. People moved around inside a large cube-shaped room with semi-transparent walls onto which stereo images were back-projected from outside. Although they didn’t have to wear HMDs, they did need stereo glasses to experience full 3D perception.

Datagloves

See something amazing and your instinct is to reach out and touch it—even babies do that. So giving people the ability to handle virtual objects has always been a big part of VR. Usually, this is done using datagloves, which are ordinary gloves with sensors wired to the outside to detect hand and figure motions. One technical method of doing this uses fiber-optic cables to stretch the length of each finger. Each cable has tiny cuts in it so, as you flex your fingers back and forth, more or less light escapes. A photocell at the end of the cable measures how much light reaches it and the computer uses this to figure out exactly what your fingers are doing. Other gloves use strain gauges, piezoelectric sensors, or electromechanical devices (such as potentiometers) to measure finger movements.

Wands

virtual reality handset controller
A typical handheld virtual reality controller (complete with elastic bands), looking not so different from a video game controller. Photo courtesy of NASA Ames Research Center.

Even simpler than a dataglove, a wand is a stick you can use to touch, point to, or otherwise interact with a virtual world. It has position or motion sensors (such as accelerometers) built-in, along with mouse-like buttons or scroll wheels. Originally, wands were clumsily wired into the main VR computer; increasingly, they’re wireless.

 

 

 

Applications of Virtual Reality

VR has always suffered from the perception that it’s little more than a glorified arcade game—a “dreamy escape” from reality. In that sense, “virtual reality” can be an unhelpful misnomer; “alternative reality,” “artificial reality,” or “computer simulation” might be better terms. The key thing to remember about VR is that it isn’t a fad or fantasy waiting in the wings to whistle people off to alternative worlds; it’s a hard-edged practical technology that’s been routinely used by scientists, doctors, dentists, engineers, architects, archaeologists, and the military for about the last 30 years. What sorts of things can we do with it?

Education

virtual reality plane trainer cockpit
Flight training is a classic application of virtual reality, though it doesn’t use HMDs or datagloves. Instead, you sit in a pretend cockpit with changing images projected onto giant screens to give an impression of the view you’d see from your plane. The cockpit is a meticulous replica of the one in a real airplane with the same instruments and controls. Photo by Javier Garcia courtesy of US Air Force.

Difficult and dangerous jobs are hard to train for. How can you safely practice taking a trip to space, landing a jumbo jet, making a parachute jump, or carrying out brain surgery? All these things are obvious candidates for virtual reality applications. As we’ve seen already, flight cockpit simulators were among the earliest VR applications; they can trace their history back to mechanical simulators developed by Edwin Link in the 1920s. Just like pilots, surgeons are now routinely trained using VR. In a 2008 study of 735 surgical trainees from 28 different countries, 68 percent said the opportunity to train with VR was “good” or “excellent” for them and only 2 percent rated it useless or unsuitable.

 

Scientific Visualization

What Is Virtual Reality? | Definition and ExamplesAnything that happens at the atomic or molecular scale is effectively invisible unless you’re prepared to sit with your eyes glued to an electron microscope. But suppose you want to design new materials or drugs and you want to experiment with the molecular equivalent of LEGO. That’s another obvious application for virtual reality. Instead of wrestling with numbers, equations, or two-dimensional drawings of molecular structures, you can snap complex molecules together right before your eyes. This kind of work began in the 1960s at the University of North Carolina at Chapel Hill, where Frederick Brooks launched GROPE, a project to develop a VR system for exploring the interactions between protein molecules and drugs.

Medicine

Apart from its use in things like surgical training and drug design, virtual reality also makes possible telemedicine (monitoring, examining, or operating on patients remotely). A logical extension of this has a surgeon in one location hooked up to a virtual reality control panel and a robot in another location (maybe an entire continent away) wielding the knife. The best-known example of this is the DaVinci surgical robot, released in 2009, of which several thousand have now been installed in hospitals worldwide. Introduce collaboration and there’s the possibility of a whole group of the world’s best surgeons working together on a particularly difficult operation—a kind of WikiSurgery if you like!

Although it’s still early days, VR has already been tested as a treatment for various kinds of psychiatric disorders (such as schizophrenia, agoraphobia, and phantom-limb pain), and in rehabilitation for stroke patients and those suffering degenerative diseases such as multiple sclerosis.

Industrial Design and Architecture

Architects used to build models out of card and paper; now they’re much more likely to build virtual reality computer models you can walk through and explore. By the same token, it’s generally much cheaper to design cars, airplanes, and other complexes, expensive vehicles on a computer screen than to model them in wood, plastic, or other real-world materials. This is an area where virtual reality overlaps with computer modeling: instead of simply making an immersive 3D visual model for people to inspect and explore, you’re creating a mathematical model that can be tested for its aerodynamic, safety, or other qualities.

Games and Entertainment

From flight simulators to race-car games, VR has long hovered on the edges of the gaming world—never quite good enough to revolutionize the experience of gamers, largely due to computers being too slow, displays lacking full 3D and the lack of decent HMDs and datagloves. All that may be about to change with the development of affordable new peripherals like the Oculus Rift.

Pros and cons of virtual reality

Like any technology, virtual reality has both good and bad points. How many of us would rather have a complex brain operation carried out by a surgeon trained in VR, compared to someone who has merely read books or watched over the shoulders of their peers? How many of us would rather practice our driving on a car simulator before we set foot on the road? Or sit back and relax in a Jumbo Jet, confident in the knowledge that our pilot practiced landing at this very airport, dozens of times, in a VR simulator before she ever set foot in a real cockpit?

Critics always raise the risk that people may be seduced by alternative realities to the point of neglecting their real-world lives—but that criticism has been leveled at everything from radio and TV to computer games and the Internet. And, at some point, it becomes a philosophical and ethical question: What is real anyway? And who is to say which is the better way to pass your time? Like many technologies, VR takes little or nothing away from the real world: you don’t have to use it if you don’t want to.

The promise of VR has loomed large over the world of computing for at least the last quarter-century—but remains largely unfulfilled. While science, architecture, medicine, and the military all rely on VR technology in different ways, mainstream adoption remains virtually nonexistent; we’re not routinely using VR the way we use computers, smartphones, or the Internet. But the 2014 acquisition of VR company Oculus, by Facebook, greatly renewed interest in the area and could change everything. Facebook’s basic idea is to let people share things with their friends using the Internet and the Web. What if you could share not simply a photo or a link to a Web article but an entire experience? Instead of sharing photos of your wedding with your Facebook friends, what if you could make it possible for people to attend your wedding remotely, in virtual reality, in perpetuity? What if we could record historical events in such a way that people could experience them again and again, forevermore? These are the sorts of social, collaborative virtual reality sharing that (we might guess) Facebook is thinking about exploring right now. If so, the future of virtual reality looks very bright indeed!

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