Building Mods with Valve Technology

Building a "mod" (a game which relies on another game's core technology, called base game, or vanilla game) is very often the best way to develop a new game. When you rely on game technology as well-established as the Source engine, your team's time and effort can be spent building creative gameplay and unique content rather than on things like rendering technology or network code or collision detection. The Source Engine and its associated SDK provide the most efficient, complete, and powerful game development package on the market. And if you already own Half-Life 2, Counter-Strike: Source or at least have Source SDK 2013 (SP, MP or Both) and/or Alien Swarm installed, you've already got access to the full SDK. That's everything you need to start building your game.

Why Source?

Here are some reasons why it makes sense to build your game as a mod using the Source Engine:

Valve

• Valve remains dedicated to supporting the mod community.
• Valve also has a proven track record for turning mods into full-fledged commercial products.

Source and Steam have been designed with mods in mind

• The SDK is updated continuously and automatically, including new features (like HDR).
• A powerful (and free!) suite of content-development tools is included.
• Source is simply the most flexible and most powerful engine on the market.
• The Source/Steam platform allows you to have a direct relationship with your players/customers.

A larger player base than all other action-game engines combined

• Mod visibility comes from being a part of the most popular platform.
• Access to a huge, established community and audience.
  • Steam games account for more than 90% of online action PC games.
  • Approximately 5 billion player-minutes per month
  • Over 100,000 game servers
  • Over million simultaneous users at any given moment

Included: all of the tools used to build Half-Life 2

• HL2 source code included
  • Also available publicly on official GitHub page. However, if you are planning to use Source engine or it's SDK commercially, you will need to contact Valve to licensing the engine.
• Softimage XSI|EXP for model building
• The Hammer level editor
  • Fully documented with images and examples
  • Complemented with in-depth community tutorials
• Faceposer
• Half-Life Model Viewer

The power of the Source Engine

In every category, the Source Engine delivers proven industry-leading performance.

• Renderer
• Materials System
• Advanced Characters
• Physics
• Advanced AI
• Multiplayer Network Code
• Sound System
• UI (VGUI)
• Programming
• Tools

Read about the features of the Source Engine.

You're ready to start building!

• Get Steam.
• Get the SDK.
• Join this community, contribute your ideas to the Wiki, discuss issues on any page, and join the mailing list, too.
• Read information on how to develop Source mods.
• Start building!