< level-editor defined

A Level-Editor is a piece of software that is increasingly shipped along with popular 3D PC games. An example of this is Worldcraft, made and used by Valve Software to create the first-person shooter game Half-Life and it's subsequent 'mods', such as Counter-Strike and Opposing Force (of which there are hundreds).

This software allows the user to design their own playable environments, using the gaming engine which drives the commercially-sold game as its foundation. It does this by providing an interface similar to a 3D-modelling program in which the user can build environments from scratch, including lighting, surfacing and surrounding organic landscapes. Within the environment the user can also control the placement of trigger-points for events to occur, such as whether doors are openable, or whether a surface that looks like glass will smash when shot at. The user can also choose the placement of various 'entities' provided by the engine, such as monsters and terrorists replete with artificial intelligence.

Once finished, the environment and all it's settings are compiled and becomes a playable 'map'. This can be posted on the Internet and downloaded by other gamers who can then open it within the parent-game and play within that map.