Virtual Reality | Research & Encyclopedia Articles

The terms virtual reality (VR) and virtual environment (VE) refer to an artificial reality created by computer technology that provides the user with a first-person, interactive view into the virtual world that has been created. It is this interactive capability that distinguishes VR from other systems based on computer graphics such as the extremely realistic computer animations that are increasingly being used by the filmmaking industry. Actors do not actually interact with the computer animations that will ultimately appear in a film. Instead, they interact with an "imaginary" scene or animation that is then added later to provide realism for the moviegoer. This provides the audience with a third-person view of a virtual world. Such a view is in sharp contrast to VR, in which the environment is centered around the perspective of the user who will also typically have the ability to interact dynamically with it.

Although its origins date back to the 1950s, the phrase "virtual reality" first became widely known in the mid-1980s, when mainstream computer technology finally become powerful enough to perform the calculations necessary to create a minimally realistic virtual environment. However, in spite of earlier technological limitations, VR ideas were envisioned long before the 1980s. In 1957 Mort Heilig filed a patent for a head-mounted "stereoscopic television apparatus for personal use." Thus, the head-mounted display (HMD) was born, though at the time, applying this technology to view a virtual world created by a computer was not considered or envisioned.

In 1965 Ivan Sutherland published an article called "The Ultimate Display," which described how a computer could someday be used to provide a window into virtual worlds. Then in 1968, Sutherland combined these ideas together with head tracking and built a head-mounted display providing a stereoscopic view into a simple 3D world that remained stationary despite viewer head movements! Virtual reality was born.

Today VR consists of much more than just head-mounted displays. Gloves containing strain gauges or fiber optics can be used to allow a user to interact with a virtual world through hand gestures. Force feedback information, such as the weight of a virtual object, can be provided via haptic devices, and a virtual reality modeling language, called VRML, has even been developed to allow Internet browsers to interact with 3D environments.

Philosophically speaking, the objective of VR is to create an environment that is believable to the user, but which does not exist in the physical world. The understanding of our world, our reality, is ultimately derived from our senses. Humans have five major senses: sight, hearing, touch, smell, and taste. These senses provide our brains with information that enables us to understand the world around us—our "reality." The most important sense for understanding the physical world is sight, followed by sound and touch.

At the present time, computer technology has enabled the development of sophisticated means to stimulate our senses of sight and hearing. To a lesser degree, the technology for stimulating touch has also been developed. A virtual environment which the brain can easily interpret as being real is created when these technologies are integrated into a system where the sensory data that are produced are consistent with (i.e., conforms to) what we have observed in the physical world.

Anyone who has experienced "motion sickness" while sitting perfectly still and watching a plane fly in a 360-degree theater will attest to the factthat the brain can be decisively tricked through visual stimulus alone. Recognizing that a large part of our understanding of reality is based on visual stimulus has led significant effort in VR research to be devoted to visual-based stimulus such as image generation and animation.

Concepts such as perspective, reflection of light, texturing, and rotation of 3D images form the basis of constructing stationary images and provide us with a way to navigate through such images. These concepts are well understood and have been precisely defined by mathematical equations. Manipulating these mathematical equations has allowed computers to generate images that are exceedingly real. However, generating such ultra-realistic images involves tremendous mathematical calculations and even the fastest computers yet made cannot support real-time animation of such images. This is why the computer animations used in movies are so much more realistic than present-day VR systems.

The next piece of the visual puzzle is animation, that is, making objects in the virtual world move. Animation is based on kinetics and kinematics. These fields of study are essentially concerned with how things move and react to forces. Although the advances in this area have been significant, there is much work that remains to be done in order for computers to be able to generate animations that are truly consistent with our understanding of the physical world. For example, we all know how people and animals walk or run, and we are very good at distinguishing "natural" motion from the motion that computer animations are presently capable of generating. We have never actually seen a dinosaur run, but when we see it in a movie, we know that its motion is close, but not quite right.

A complementary technique that can be used to amplify the realism of a virtual word is called immersion. A user can be immersed in a virtual world by removing the conflicting stimulus associated with the physical world. In other words, it is easier for someone to imagine she is in a virtual world if she is only allowed to see that virtual world and nothing else. Immersion is what makes 360-degree theaters so realistic.

As with all technologies, the use of virtual reality is often limited only by the imagination of the user. In movies like The Lawnmower Man and The Matrix, Hollywood shows a more sinister look at how VR might someday be abused. However, the ability to create realistic virtual environments has the potential to benefit society significantly. This stems from the fact that a virtual environment is a model of reality. Models typically do not contain every aspect of the thing they are modeling. What this means in the context of VR is that in a virtual environment, the rules of the physical world can be broken or bent!

For example, a pilot can learn to fly a commercial airliner in a virtual environment, without having to worry about experiencing the consequences associated with an actual crash. Fly-by-wire systems or new airplane designs can be tested without the cost or worry of crashing an aircraft. Surgeons can master complex operations without having to worry about accidentally killing a patient. The effects of a nuclear reactor meltdown can be studied without any risk to the environment. New designs for supertankers that minimizeoil spillage in the event of a collision can be studied without the cost associated with physically testing. The list of interesting and useful applications of VR is long and growing rapidly.

Interactive Systems; Optical Technology; Simulation; Simulators; Virtual Reality in Education.

Hollands, Robin. The Virtual Reality Homebrewer's Handbook. New York: John Wiley & Sons, 1996.

Vince, John. Essential Virtual Reality Fast: How to Understand the Techniques and Potential of Virtual Reality. New York: Springer-Verlag, 1998.

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