User modifications, or user mods for short, are alterations made to a piece of software (usually a game) in order to customize its content and/or allow players to alter or modify various aspects of the application. User modifications can include aesthetic changes (alteration, removal, or addition of new models, textures, or skins), auditory changes (alteration, removal, or addition of new music or sound effects), or core gameplay changes.
Skins (commonly referred to as textures) are user modifications that change the appearance of weapons, hats, player models, or any other part of a game. Skins are unofficial and not supported by Valve. Some weapons, such as the Homewrecker, Dalokohs Bar, and Vita-Saw, were originally created as skins and later incorporated into the game by Valve.
Skins can be created, downloaded, and installed by players; they usually aim to change the materials, textures, or models of a particular aspect of a game such as a weapon or character. Most skins are client-side, meaning that they show up only for the person who has them installed. Server owners can apply server-side skins which are viewable by anyone who joins the server.
Skins are used almost entirely for cosmetic and aesthetic purposes. They can range from simple retexturing to full-on recreations of certain game aspects. Skins do not change the stats or effects of any items or any aspect of the game except in the case of skins deliberately designed as "cheats", such as a skin that re-textures walls to be transparent.
Players can create their own skins using material-modifying or image-editing programs, such as Photoshop or GIMP, or 3D modeling and animating programs, such as Blender or 3DMax. Multiple tutorials on different aspects of skinning are available online.
Previously, creators of new models had to use cheats in order to test and view their community skins and models. With the addition of the Steam Workshop, individuals are now able to submit their creations in order for them to be judged and added to Team Fortress 2's items database. With the addition of the map Itemtest, mod makers are now able to test their models more effectively in order for them to be contributed to the community.
Skins are typically accompanied by instructions outlining how to install them. Most are installed somewhere under the directory steam/steamapps/common/Team Fortress 2/tf/custom.
You can grab the files and drag them into the tf folder in the Team Fortress 2 files.
User sound modifications
User sound modifications are modifications that change the music or sound effects of a game's weapons, characters or classes, voices, objects, maps, locations, or any other part of a game's audio. User sound modifications are unofficial and not supported by Valve.
User sound modifications can be created, downloaded, and installed by players. They usually aim to change the sound effects, music, or speech for a particular aspect of a game, such as a weapon's reloading or firing sound or a character's voice responses. Most user sound modifications are client-side, meaning that they are audible only for the person who has them installed. Server owners are able to apply server-side user sound modifications that are audible to anyone who joins the server.
User sound modifications are used almost entirely for novelty purposes or entertainment. They can range from simple music or sound effect changes to full-on audio replacements of certain voice responses or weapon sounds. They are often used in conjunction with new weapon skins or models in order to create a unique weapon and accompanying sound effect set. User sound modifications do not change the stats or effects of any items or any aspects of the game (except in the case of sounds deliberately designed as "cheats", e.g. increasing the volume on the Spy's decloaking sound effect in order to make it more noticeable.
There are many websites that feature downloadable sounds for Team Fortress 2, the most popular being GameBanana.
Players can create their own user sound modifications using sound-editing programs, such as Audacity. Multiple tutorials on different aspects of sound modding are available online.
Testing and installing user sound modifications
User sound modifications are typically accompanied by instructions outlining how to install them. Most are installed somewhere under the directory steam/steamapps/common/Team Fortress 2/tf/custom. Once installed, user sound modifications should work immediately whenever the default sound effect would normally be played.
The exception for this is replacement of main menu music. It is possible to add new music, but it is not possible to change the default music. Any replacements for the menu music are automatically reverted to the defaults when TF2 launches.
User modifications as cheats
While most user sound modifications and skins are used to improve or slightly alter the auditory and visual aspects of the game, respectively, some user modifications and skins are designed in order to attempt to provide users with an unfair advantage. These include, but are not limited to:
- Sometimes HUDs can be modified to be able to detect disguised Spies.
- Seeing players/items through walls. This has included the presents on Halloween.
- Glow-in-the-dark enemies.
- Colored bodies with different colored heads.
- Syringe Gun Trails
- Show only the hitboxes of players.
- Skewed to show locations.
- "Giant head" to see player locations behind obstacles.
- "Bubble" around pickups.
- Attached to models to make them more visible.
- Show the location of cloaked Spies.
- Increasing the volume of certain effects in order to alert players from a larger distance, such as Sentry Gun beeps and Spies decloaking.
Due to their nature, these kinds of cheats are not detected by VAC, which only deals with external programs or altered game code. Some protection for servers does exist if the 'sv_pure' console variable [default 0] is set to '1' (a whitelist is created) or to '2' (players on a server are forced to use Team Fortress 2's default content). For more information, please see the Pure Servers article on the VDC.