Question!

[Ichabod]

Are the editing tools the only programs you can build the maps in, or can you start in another 3d modeling program and move over to those?

[Chilly]

You can only use Hammer for TF2 mapping. The Hammer version for L4D includes the ability to import from Google Sketchup, meaning you can position stuff like walls and do general layout then take it into Hammer to detail everything. Pretty much any 3D modeling program can be used to actually create custom models used in the game, but not entire maps. Think of the custom cart on Hoodoo or custom models like trees, props, etc.

[Ichabod]

Alrighty, thanks