Total conversion

A total conversion, in the computer gaming sense, is a mod (short for "modification") of an existing game where the end result bears little resemblance to the original on which the conversion was based. Many games provide players with the ability to edit the game's many elements: levels, sounds, enemies, and so on. Most modifications are limited in scope, resulting in a partial conversion. Total conversions are less common, mainly because of the large amount of development and man-time needed to bring a whole project together.

An example of a well-known total conversion is Counter-Strike, which is based on the Half-Life engine. Half-Life is a linear, single-player first-person shooter with some puzzle solving, where you take the place of a character named Gordon Freeman. The earth is under attack by aliens, and the weapons used to destroy them tend to be futuristic. In contrast, Counter-Strike is a round-based, multiplayer-only game, based on realistic settings between Terrorists and Counter-Terrorists. Gameplay is centralised around goals of disarming bombs or rescuing hostages, and all weaponry is modelled on existing arms — including design, use, and sound effects. Practically the only thing that Counter-Strike has in common with Half-Life is that Counter-Strike originally required Half-Life to be installed for it to run.

In Science, or more accurately in Science Fiction, the phrase total conversion refers to the idea of converting 100% of mass into energy. The first reference to such a process may have occurred in the classic Robert A. Heinlein short story Universe, which certainly was the first to describe a large, slow multi-generational starship. Its power source was called "the Converter".

It should be noted that the concept of combining ordinary matter with antimatter, which indeed can convert 100% of mass into energy and was popularized by the 1960s TV series Star Trek, is usually called "annihilation". The Universe is not known to possess large natural supplies of antimatter, and current theoretical thinking is that it actually doesn't. Antimatter can be manufactured, but doing so requires using at least as much energy as would later be released during annihilation. Nevertheless, manufactured antimatter is expected to someday be useful as a form of extremely concentrated stored energy, for special purposes such as powering spaceships.

Modern developments in Physics have yielded the possibility that there may be a way to actually convert 100% of ordinary matter into energy. The physicist Stephen Hawking showed that a black hole can interact with virtual particles in the vacuum in such a way that the black hole can "evaporate". For most black holes (possessing stellar mass) the evaporation process takes place extremely slowly, but the smaller it gets, the faster it evaporates (provided nothing falls into the black hole while all this is going on). The actual "evaporant" is a flow of subatomic particles from the hole, travelling at nearly the speed of light. Due to the nature of virtual particles, the escaping particles should be roughly a 50/50 mix of ordinary particles and antimatter particles. The implication is that if we started with an appropriately small black hole, which was suffering from a fierce rate of escaping particles, we could deliberately inject ordinary matter into the hole to compensate for the mass it loses that way. Then we gather up the escaping particles and allow them to annihilate each other. The net effect is the total conversion of the ordinary matter which is fed to the black hole, into the pure energy of the annihilated escaped particles. However, depending on what total percentage of the escaping particles are neutrinos, this particular total conversion process may be problematic. We know of no way to "gather up" neutrinos and make them annihilate with anti-neutrinos. So, this may turn out to be less useful than the "accretion disc" phenomenon, even though accretion can convert no more than 40% of mass into energy. (By comparison, the nuclear fusion of hydrogen that powers the stars only converts about 1%.)de:Total Conversion