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A virtual world is a computer-based simulated environment intended for its users to inhabit and interact via avatars. This habitation usually is represented in the form of two or three-dimensional graphical representations of humanoids (or other graphical or text-based avatars). Some, but not all, virtual worlds allow for multiple users.
The virtual world spectrum includes:
Another name used widely for 3D fully immersive environments is metaverse. The term metaverse comes from Neal Stephenson’s 1992 novel Snow Crash, and is now widely used to describe the vision behind current work on fully immersive 3D virtual spaces. These are environments where humans interact (as avatars) with each other (socially and economically) and with software agents in a cyber space, that uses the metaphor of the real world, but without its physical limitations.
Virtual reality (VR) is a technology which allows a user to interact with a computer-simulated environment, be it a real or imagined one. Most current virtual reality environments are primarily visual experiences, displayed either on a computer screen or through special or stereoscopic displays, but some simulations include additional sensory information, such as sound through speakers or headphones. Some advanced, haptic systems now include tactile information, generally known as force feedback, in medical and gaming applications. Users can interact with a virtual environment or a virtual artifact (VA) either through the use of standard input devices such as a keyboard and mouse, or through multimodal devices such as a wired glove, the Polhemus boom arm, and omnidirectional treadmill. The simulated environment can be similar to the real world, for example, simulations for pilot or combat training, or it can differ significantly from reality, as in VR games. Processing power, image resolution and communication bandwidth are currently limiting the attempts to create a high-fidelity virtual reality experience.
In a virtual reality environment, a user experiences immersion, or the feeling of being inside and a part of that world. He is also able to interact with his environment in meaningful ways. The combination of a sense of immersion and interactivity is called telepresence. Computer scientist Jonathan Steuer defined it as “the extent to which one feels present in the mediated environment, rather than in the immediate physical environment.â€
The degree of interactivity varies from:
to
Input devices:
More on the topic:
Illustrations:
Augmented reality (AR) is a field of computer research which deals with the combination of real world and computer generated data. At present, most AR research is concerned with the use of live video imagery which is digitally processed and "augmented" by the addition of computer generated graphics. Advanced research includes the use of motion tracking data, fiducial marker recognition using machine vision, and the construction of controlled environments containing any number of sensors and actuators.
Ronald Azuma's definition of AR is one of the more focused descriptions. It covers a subset of AR's original goal, but it has come to be understood as representing the whole domain of AR: Augmented reality is an environment that includes both virtual reality and real-world elements. For instance, an AR user might wear translucent goggles; through these, he could see the real world, as well as computer-generated images projected on top of that world. Azuma defines an augmented reality system as one that
* Combines real and virtual. * Is interactive in real-time. * Is registered in 3D.
Reference: Azuma, Ronald T. "A Survey of Augmented Reality". Presence: Teleoperators and Virtual Environments 6, 4 (August 1997), 355–385.
Illustrations:
http://hinchcliffe.org/img/twowaywebwithid20.jpg
Identity 2.0 diagram from the Web Services Journal article by Dion Hinchcliffe
More information in these presentations:
