The official editor for Fallout 3 and Fallout: New Vegas, called G.E.C.K. (Garden of Eden Creation Kit, named after the terraforming device of the same name from the series), that can be downloaded for free, allows PC users to create and add their own content to the game. The editor requires a pre-existing installation of the associated game to function, as it requires the usage of several resources within the game.
The G.E.C.K. provides the community with tools that allow players to expand the game. Users can create and edit any data for use with Fallout 3 or Fallout: New Vegas, from building landscapes, towns, and locations to writing dialogue, creating characters, weapons, creatures, and complex scripting.
The G.E.C.K. has an interface similar to that of The Elder Scrolls Construction Set, which is useful to those who are familiar with it; however, the functionality of the G.E.C.K. is far expanded over that of the Construction Set, much like the functionality of the game engine. Scripting options for the G.E.C.K. can be expanded using the Fallout 3 Script Extender or New Vegas Script Extender (or FOSE and NVSE, respectively) much like OBSE for TES IV: Oblivion and SKSE for TES V: Skyrim; however, these script extenders are not compatible with versions purchased via Direct2Drive, and having Games For Windows Live active will cause the game to crash as soon as you try to access Games For Windows Live.
The first version 1.1 was made available on December 11, 2008. On May 26, 2009, an update to version 1.5 was released. It requires version 1.1 to be installed. With the launch of the new official website for games from the Fallout series, these versions now are only available from the Garden of Eden Creation Kit wiki, hosted on a Zenimax server.
Fallout: New Vegas
The first version for Fallout: New Vegas was made available on October 19, 2010, concurrent with the game's U.S. release. It was later updated to the working version 1.4, which also is available on the Garden of Eden Creation Kit wiki, hosted on a Zenimax server. As of May 20th, 2013, the G.E.C.K. is available for download via Steam.
The G.E.C.K. does not work with this game. xEdit and/or the Creation Kit are used for creating mods and examining the game files. The Creation Kit is available for download only from the Bethesda.net launcher.
The G.E.C.K. does not work with this game, and plugins are not supported. A modified version of xEdit is used to examine the game files.