Immersion into virtual reality is a perception of being physically present in a non-physical world. The perception is created by surrounding the user of the VR system in images, sound or other stimuli that provide an engrossing total environment.
The name is a metaphoric use of the experience of applied to representation, fiction or simulation. Immersion can also be defined as the state of consciousness where a "visitor" (Maurice Benayoun) or "immersant" (Char Davies)'s awareness of physical self is transformed by being surrounded in an artificial environment; used for describing partial or complete suspension of disbelief, enabling action or reaction to stimulations encountered in a virtual or artistic environment. The degree to which the virtual or artistic environment faithfully reproduces reality determines the degree of suspension of disbelief. The greater the suspension of disbelief, the greater the degree of presence achieved.
According to Ernest W. Adams, author and consultant on game design, immersion can be separated into three main categories:
Staffan Björk and Jussi Holopainen, in Patterns In Game Design, divide immersion into similar categories, but call them sensory-motoric immersion, cognitive immersion and emotional immersion, respectively. In addition to these, they add a new category:
Presence, a term derived from the shortening of the original "telepresence," is a phenomenon enabling people to interact with and feel connected to the world outside their physical bodies via technology. It is defined as a person's subjective sensation of being there in a scene depicted by a medium, usually virtual in nature (Barfield et al., 1995). Most designers focus on the technology used to create a high-fidelity virtual environment; however, the human factors involved in achieving a state of presence must be taken into account as well. It is the subjective perception, although generated by and/or filtered through human-made technology, that ultimately determines the successful attainment of presence (Thornson, Goldiez, & Le, 2009).
Virtual reality glasses can produce a visceral feeling of being in a simulated world, a form of spatial immersion called Presence. According to Oculus VR, the technology requirements to achieve this visceral reaction are low-latency and precise tracking of movements.