Left 4 Dead 2 is great fun, but there are only so many maps that actually come with the game. And until Valve releases any additional map packs, community-created maps are your best bet for fresh content. But why not learn how to make your own custom maps? With Valve's Hammer World Editor and Google's free SketchUp program, it's actually much easier than you think. 

Valve's Hammer is the game map editor that comes with the Left 4 Dead Software Development Kit (SDK). Google SketchUp is a free 3D design application that has myriad uses. Using both tools, you can design and make custom shapes and objects that would be impossible to generate with Hammer alone.

We're going to show you, step-by-step, how to use these tools to make a single Survival map for Left 4 Dead. We'll cover the basics of Hammer, the art of designing a building from a reference photo, and crafting simple objects to use in-game. The techniques we introduce apply to both Left 4 Dead and Left 4 Dead 2. They'll also help you make maps for other Source engine games, like Counter-Strike, Half-Life 2, Portal, and Team Fortress 2. 

Grab and seat and dive in. Making a Left 4 Dead map is a perfect D-I-Y project for the Holiday weekend