Computer-based systems that supply the visual and aural effects to project the viewer into an imaginary environment beyond the screen. The user is supplied with computer-generated images and sounds giving the impression of reality. The user interacts with the artificial world by means of sensors and apparatus including helmets ("visiocasque") and gloves which link the user's perceptions and movements and the audio-visual effects. Future work in virtual reality is directed towards increasing the impression of reality, for example by means of 3D images, and transmitting "virtual reality worlds" to users located remotely from the source computer.