TES Construction Set 1.2.404

The Elder Scrolls (TES) Construction Set is editing software for the video games The Elder Scrolls III: Morrowind and The Elder Scrolls IV: Oblivion; the Morrowind version was shipped with the game while the Oblivion version is available for download. It gives full and complete control of the game's content to anyone willing to spend some time figuring it out. In fact, it is the very tool that Bethesda Softworks, the developers of Morrowind and Oblivion, used to create the game worlds. Though Bethesda now utilizes a newer version to create official plugins for Oblivion, the two Morrowind and Oblivion versions are not backwards compatible. The Construction Set allows fans to edit the game world directly and save their own alterations as .esp (Elder Scrolls plugin) files, the proprietary filetype for Morrowind plugins. In order to allow more complex interactions between mods, and intereliance of different mods, many mods are converted to .esm (Elder Scrolls Master) files. Third party tools are needed for this type of process. (See below)

Fans exchange these plugins (or 'mods') freely online and, through them, they can change anything about the game from creating new character abilities to adding huge mansions into the side of a cliff overlooking a city or creating an entirely new plotline. The overall file sizes of plugins can be as small as a few kilobytes because they may just edit basic game settings, such as the amount of gravity, though they can also be much larger (100 megabytes or more).

Most larger plugins also provide additional files that were not included with the game, such as textures and 3D models (or 'meshes') which provide brand new artwork within the game. Often these must be manually moved to the proper place within the game folder structure to become useful. However, some plugins are packaged in archives which can easily be uncompressed directly to the correct game folders with no need for manual placement.