Modification
A modification, often abbreviated to mod, is an alteration or creation of files for a game engine, which allow it to modify the gameplay style, graphics, environments, models, etc.
Mods in a broad sense can be a game like
Portal Stories: Mel. Mods in the narrow sense add something to the game like
Synergy. Some games like
Half-Life 2: Update or
The Stanley Parable are difficult to define as just one.
Types of Mods
- Third-party modifications are mods that has not been developed by the original game designer. Mods are typically third-party, as first-party mods are often called expansions (or DLC, short for Downloadable Content). Third-party mods usually runs on Source SDK Base, but some mods might run on top of Half-Life 2 or other games.
- Content-only mods (which includes Steam Workshop addons) are mods that simply replace the original game assets (such as replacing models, textures, sound, etc.), without changing any game code.
- Total conversions (sometimes abbreviated TC) are mods that have altered their original games to such extents (through new models, new animations, new code, among other things) that their original games can no longer be recognized. The amount of work and expertize required for total conversions, makes these types of mods very rare.
- Dead modifications are mods that (often due to loss of interest or internal problems) have ceased development and been abandoned without producing a release.
Installing Source Engine mods
To install a modification manually, follow these instructions:
Method 1:
- 1. Copy the mod folder (with the gameinfo.txt file directly inside) into your
sourcemodsfolder. (usually…\Steam\SteamApps\sourcemods), for example:
Windows: C:\Program Files\Steam\SteamApps\sourcemods[for 32-bit Windows]C:\Program Files (x86)\Steam\SteamApps\sourcemods[for 64-bit Windows].
macOS: ~/Library/Application Support/Steam/SteamApps/sourcemods[confirm]
Linux: ~/.local/share/Steam/steamapps/sourcemods[for normal installation]~/.var/app/com.valvesoftware.Steam/steamapps/sourcemods[for Flatpak installation]
- 2. Start/Restart Steam. If the mod is available for play, Steam should list it in your Games library.
sourcemods folder must be on the same drive as Steam is installed. If there is insufficient drive space, it can instead be installed manually in the base game's directory (see method 2).Method 2:
- 1. Copy the mod folder (again, with the gameinfo.txt file directly inside) into
\Steam\SteamApps\common\Source SDK Base 2013 SingleplayerorSource SDK Base 2013 Multiplayerfolder. - 2. Launch hl2.exe with
-steam -game "(mod folder name)"command-line parameters. Or you can add the same launch options to Source SDK Base 2013 on Steam games library, then click Play.
Installing GoldSrc mods
To install a modification for
GoldSrc-based games (such as
Half-Life), follow these instructions:
- 1. Do the same Method 2 as the Source engine, but instead copy mod folder to
\Steam\SteamApps\common\Half-Life(for
Half-Life) folder. - 2. Start/Restart Steam. If the mod is available for play, Steam should list it in your Games library (except in Quake).
OR
Launchhl.exewith-game "(mod folder name)"command-line parameters. Or you can add the same launch options to Half-Life on Steam games library, then click Play.
Install content mods
Source
To install content-based mods, such as custom models, texture, audio, etc. for Source games, follow these instructions:
- Steam Workshop
- Simply click "Subscribe". Some games may require restart to download addons.
- VPKs -

- Drop to
game-name\custom - VPKs -
(and above), aswell
legacy addons/folder-based addons. - Drop to
game-name\addonsfolder
- Folders (containing
materials,models,sound, etc. inside it) -
- Drop to
game-name\custom
Note:Example: game-name\custom\My mod name\.
game-name is the name of the mod (or game folders). For Half-Life 2, the folder will be named hl2.GoldSrc
To install content-based mods, such as custom models, texture, audio, etc. for GoldSrc games, follow these instructions:
game-name_addonfolder - Simply create the folder, with the game name on it, and ends with_addon(example:valve_addonfor
), then put your custom texture (WADs), models and/or sound there.
- This is only available on GoldSrc games post-SteamPipe.
- Overwrite files - Simply overwrite files in
game-namewith one from the zip. Note that this method is no longer recommended for updated
games.
game-name is the name of the mod (or game folders). For Half-Life, the folder will be named valve.See also
- A list of GoldSource (Half-Life) mods and Source mods.
- Help:Mod Profiles - Rules and guidelines for writing new mod articles here.
- Map pack - A pack of maps, which is different from a mod.