ABSTRACT
Virtual reality (VR) refers to technologies that can permit users to experience and interact with environments that are entirely computer generated. A large part of such environments are visual, using computer screens, multiscreen projection systems, shutter glasses to provide 3D eff ects, and various kinds of headmounted displays, but may also include rich audio capability, haptic (tactile) interfaces, various means for locomotion within the virtual world, and even olfaction (smell). e environments created using these techniques may represent the real world, or an entirely artifi cial world, or some combination of both. For the purposes of this chapter, two additional concepts will be considered within the scope of VR: mixed reality (MR) and augmented reality (AR). Milgram and Kishino (1994) defi ned what they call the virtuality continuum (Figure 12.1) that has at one end sensed reality in the real world, and at the other extreme VR in which the sensed world is entirely artifi cial. In between these is the world of MR, in which some elements of the world being sensed and with which a user is interacting are physically real while some are artifi cially generated.
