Create a Mod

The Create a Mod wizard automates the process of creating a Source mod. It:

• Creates a new mod under steamapps\SourceMods\
• Installs a copy of the source code, with associated Visual Studio Project File
• Creates a Game Configuration for your mod in the Source SDK

Note:You will need to restart Steam for a new mod to appear in your library.

Engine branch

Before starting a mod you need to choose which version of Source you will use. Change the SDK's engine version to the one you want.

Source 2006

Outdated - Original Half Life 2: Episode One mod. Only included for backwards compatibility reasons.

Source 2007

Original Orange Box mod. This is the most recent HL2-Based engine branch available. This is what most mods use!

Source 2009

Updated Orange Box mod. This is the current version of the engine with Mac support. However, you cannot make a mod for Source 2009; you can make a content-only mod of a 2009 game by following Creating a Mod manually.

Alien Swarm (via Alien Swarm SDK)

The oddball of the bunch. Alien Swarm is totally free to play and its SDK includes source code, but it's source code is for a top-down shooter. It also lacks many of the HL2-compatible code's peripheral tools (including custom shader support) and cannot access HL2's content.

Source 2013

In 2013, Valve phased out the Source SDK with the release of SteamPipe. With this change, they updated the source code to the latest version of the Source-1-Engine for the HL2-based engine branch. This time around, the source code is not made available via an SDK launcher, but is instead hosted on Github. See Source SDK 2013 for more information.

Warning:Your Engine Version in the Source SDK must match the Engine branch of your mod! Failing to do this will result in Source SDK tools being unable to load required resources.

The SDK wizard

Project type

This section only applies to Half-Life 2 Mods!

When you start the wizard, you will have to choose which project to work with.

Half-Life 2 Single Player

Projects for Episode One (2006) or Two (2007). If you do not own Ep1/2 this option will be greyed out.

Half-Life 2 Multiplayer

Projects for Half-Life 2: Deathmatch. This option is only available if you own Half-Life 2: Deathmatch; otherwise it will be greyed out.

Multiplayer mod from template

A specially-created SDK project that allows you to configure settings such as if your mod is team based, or if you have abilities such as sprinting and prone. This option does not require Half-Life 2: Deathmatch.

Source code only

Dumps the code without creating an actual mod. This option is handy if you are just creating a server plugin.

Whichever option you choose, you get the same actual source code files (even if you didn't own one or another game). You also get an "everything" solution which includes a collection of development tools.

Mod Information

The first option on this page is where you want the source code extracted to. The second is the name you want to use, which also defines the output folder for your compiled content (does not appear if you chose source code only).

Creating a mod manually

It's surprisingly simple:

1. Create a folder under steamapps\SourceMods\ (A mod can actually reside anywhere, but placing it here allows Steam to detect and launch it.)
2. Create a gameinfo.txt in the folder. You now have a mod!
3. Open the SDK launcher and switch to the relevant engine branch.
4. Choose "Edit Game Configurations" and click "Add". Enter your mod's name and folder.

To get the source code (or indeed any other files of Valve's that you want to modify) you will need to use GCFScape and access depot_211_dir.vpk in the Steam\SteamApps\common\SourceSDK\vpks folder. Remember to change the custom build steps to point to your mod's folder.