moving three dimensional images which may be in colour, with 100% peripheral vision, binaural sound, scents and air breezes".Around the same time, Douglas Engelbart used computer screens both as input and output devices.The Virtual Reality Modelling Language (VRML), first introduced in 1994, was intended for the development of "virtual worlds" without dependency on headsets.
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 in medical, video gaming and military training applications.
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.
In 1938, 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.