Virtual world

A virtual world (also called a virtual space) is a computer-simulated environment which may be populated by many users who can create a personal avatar, and simultaneously and independently explore the virtual world, participate in its activities and communicate with others. These avatars can be textual, graphical representations, or live video avatars with auditory and touch sensations. Virtual worlds are closely related to mirror worlds.

In a virtual world, the user accesses a computer-simulated world which presents perceptual stimuli to the user, who in turn can manipulate elements of the modeled world and thus experience a degree of presence.
Such modeled worlds and their rules may draw from reality or fantasy worlds. Example rules are gravity, topography, locomotion, real-time actions, and communication. Communication between users can range from text, graphical icons, visual gesture, sound, and rarely, forms using touch, voice command, and balance senses.

Massively multiplayer online games depict a wide range of worlds, including those based on the real world, science fiction, super heroes, sports, horror, and historical milieus. Most MMORPGs have real-time actions and communication. Players create a character who travels between buildings, towns, and worlds to carry out business or leisure activities. Communication is usually textual, but real-time voice communication is also possible. The form of communication used can substantially affect the experience of players in the game. Media studies professor Edward Castronova used the term "synthetic worlds" to discuss individual virtual worlds, but this term has not been widely adopted.

Virtual worlds are not limited to games but, depending on the degree of immediacy presented, can encompass computer conferencing and text-based chatrooms.

History

The concept of virtual worlds significantly predates computers. The Roman naturalist, Pliny the Elder, expressed an interest in perceptual illusion. In the twentieth century, the cinematographer Morton Heilig explored the creation of the Sensorama, a theatre experience designed to stimulate the senses of the audience—vision, sound, balance, smell, even touch (via wind)—and so draw them more effectively into the productions

Among the earliest virtual worlds implemented by computers were virtual reality simulators, such as the work of Ivan Sutherland. Such devices are characterized by bulky headsets and other types of sensory input simulation. Contemporary virtual worlds, in particular the multi-user online environments, emerged mostly independently of this research, fueled instead by the gaming industry but drawing on similar inspiration. While classic sensory-imitating virtual reality relies on tricking the perceptual system into experiencing an immersive environment, virtual worlds typically rely on mentally and emotionally engaging content which gives rise to an immersive experience.

Maze War was the first networked, 3D multi-user first person shooter game. Maze introduced the concept of online players in 1973–1974 as "eyeball 'avatars' chasing each other around in a maze." It was played on ARPANET, or Advanced Research Projects Agency Network, a precursor to the Internet funded by the United States Department of Defense for use in university and research laboratories. The initial game could only be played on an Imlac, as it was specifically designed for this type of computer.

The first virtual worlds presented on the Internet were communities and chat rooms, some of which evolved into MUDs and MUSHes. The first MUD, known as MUD1, was released in 1978. The acronym originally stood for Multi-User Dungeon, but later also came to mean Multi-User Dimension and Multi-User Domain. A MUD is a virtual world with many players interacting in real time. The early versions were text-based, offering only limited graphical representation and often using a Command Line Interface. Users interact in role-playing or competitive games by typing commands and can read or view descriptions of the world and other players. Such early worlds began the MUD heritage that eventually led to massively multiplayer online role-playing games, more commonly known as MMORPGs, a genre of role-playing games in which a large number of players interact within a virtual world.

Some prototype virtual worlds were '' WorldsAway'', a two-dimensional chat environment where users designed their own avatars; '' Dreamscape,'' an interactive community featuring a virtual world by CompuServe; Cityspace, an educational networking and 3D computer graphics project for children; and '' The Palace'', a 2-dimensional community driven virtual world. However, credit for the first online virtual world usually goes to ''Habitat'', developed in 1987 by LucasFilm Games for the Commodore 64 computer, and running on the Quantum Link service (the precursor to America Online).

In 1996, the city of Helsinki, Finland with Helsinki Telephone Company (since Elisa Group) launched what was called the first online virtual 3D depiction intended to map an entire city. The Virtual Helsinki project was eventually renamed Helsinki Arena 2000 project and parts of the city in modern and historical context were rendered in 3D.

In 1999, Whyville.net the first virtual world specifically for children was launched with a base in game-based learning and one of the earliest virtual currency-based economies. Shortly after, in 2000, Habbo launched and grew to become one of the most popular and longest running virtual worlds with millions of users around the world.

Virtual world concepts

Definitions for a "virtual world" include:
* ''"A virtual world is something with the following characteristics: It operates using an underlying automated rule set—its physics; Each player represents an individual "in" the virtual world-that player’s character; Interaction with the world takes place in real time—if you do something, it happens pretty much when you do it; The world is shared-other people can play in the same world at the same time as you; The world is persistent-it’s still there when you’re not; It’s not the real world"'', by Richard Bartle in 2015
* ''"A simulated environment where many agents can virtually interact with each other, act and react to things, phenomena and the environment; agents can be zero or many human(s), each represented by many entities called a virtual self (an avatar), or many software agents; all action/reaction/interaction must happen in a real-time shared spatiotemporal nonpausable virtual environment; the environment may consist of many data spaces, but the collection of data spaces should constitute a shared data space, one persistent shard"'', by Nevelsteen in 2018

There is no generally accepted definition of virtual world, but they do require that the world be persistent; in other words, the world must continue to exist even after a user exits the world, and user-made changes to the world should be preserved.
While the interaction with other participants is done in real-time, time consistency is not always maintained in online virtual worlds. For example, ''EverQuest'' time passes faster than real-time despite using the same calendar and time units to present game time.

As ''virtual world'' is a general term, the virtual environment supports varying degrees of play and gaming. Some uses of the term include
* Massively multiplayer online games (MMOGs) games in which a large number of players interact within a virtual world. The concept of MMO has spread to other game types such as sports, real-time strategy and others. The persistence criterion is the only criterion that separates virtual worlds from video games, meaning that some MMO versions of RTS and FPS games resemble virtual worlds; ''Destiny'' is a video game that is such a pseudo virtual world. Emerging concepts include basing the terrain of such games on real satellite photos, such as those available through the Google Maps