Редактирование: Transhumanist FAQ Live (раздел)

===What is virtual reality?===

A virtual reality is a simulated environment that your senses perceive as real.

Theatre, opera, cinema, television can be regarded as precursors to virtual reality. The degree of immersion (the feeling of “being there”) that you experience when watching television is quite limited. Watching football on TV doesn’t really compare to being in the stadium. There are several reasons for this. For starters, even a big screen doesn’t fill up your entire visual field. The number of pixels even on high-resolution screens is also too small (typically 1280*1224 rather than about 5000*5000 as would be needed in a flawless wide-angle display). Further, 3D vision is lacking, as is position tracking and focus effects (in reality, the picture on your retina changes continually as your head and eyeballs are moving). To achieve greater realism, a system should ideally include more sensory modalities, such as 3D sound (through headphones) to hear the crowd roaring, and tactile stimulation through a whole-body haptic interface so that you don’t have to miss out on the sensation of sitting on a cold, hard bench for hours.

An essential element of immersion is interactivity. Watching TV is typically a passive experience. Full-blown virtual reality, by contrast, will be interactive. You will be able to move about in a virtual world, pick up objects you see, and communicate with people you meet. (A real football experience crucially includes the possibility of shouting abuse at the referee.) To enable interactivity, the system must have sensors that pick up on your movements and utterances and adjust the presentation to incorporate the consequences of your actions.

Virtual worlds can be modeled on physical realities. If you are participating in a remote event through VR, as in the example of the imagined football spectator, you are said to be telepresent at that event. Virtual environments can also be wholly artificial, like cartoons, and have no particular counterpart in physical reality. Another possibility, known as augmented reality, is to have your perception of your immediate surroundings partially overlaid with simulated elements. For example, by wearing special glasses, nametags could be made to appear over the heads of guests at a dinner party, or you could opt to have annoying billboard advertisements blotted out from your view.

Many users of today’s VR systems experience “simulator sickness,” with symptoms ranging from unpleasantness and disorientation to headaches, nausea, and vomiting. Simulator sickness arises because different sensory systems provide conflicting cues. For example, the visual system may provide strong cues of self-motion while the vestibular system in your inner ear tells your brain that your head is stationary. Heavy head-mounted display helmets and lag times between tracking device and graphics update can also cause discomfort. Creating good VR that overcomes these problems is technically challenging.

Primitive virtual realities have been around for some time. Early applications included training modules for pilots and military personnel. Increasingly, VR is used in computer gaming. Partly because VR is computationally very intensive, simulations are still quite crude. As computational power increases, and as sensors, effectors and displays improve, VR could begin to approximate physical reality in terms of fidelity and interactivity.

In the long run, VR could unlock limitless possibilities for human creativity. We could construct artificial experiential worlds, in which the laws of physics can be suspended, that would appear as real as physical reality to participants. People could visit these worlds for work, entertainment, or to socialize with friends who may be living on the opposite site of the globe. Uploads [see “What is uploading?”], who could interact with simulated environments directly without the need of a mechanical interface, might spend most of their time in virtual realities.