Left 4 Dead 2 SDK is OUT!

We are releasing the Left 4 Dead 2 Authoring Tools and Left 4 Dead 2 Add-on Support today.

PLAYERS: If you are not looking to design but play custom campaigns all you need to do is install the add-on support package. Just go into steam and open up the Tools tab. Look for the entry labeled Left 4 Dead 2 - Add-on Support click and install it. This download is sizable, but will update your L4D2 installation to allow running ANY map, including custom maps made for the original Left 4 Dead. Once installed, you do not need to run this application, it will always be active.

We will be updating the Left 4 Dead 2 game UI to include links to this package when applicable but for now please just download it directly. If you see any missing textures or models from your favorite map let us know in the forums.

DESIGNERS: Besides also downloading the above file you will need to download the Left 4 Dead 2 - Authoring Tools. Downloading it will add applications, utilities, and example files that are useful for building L4D2 game add-ons. These are similar to the tools released for Left 4 Dead, but include many updates and new features. Among the most useful are:

Gamemode Logic: Designers can now make a single map that can behave differently depending on the gamemode in which it is being played. This can dramatically reduce the file size of Campaign add-ons, as the same map can be used for Co-op, Versus, Scavenge, and Survival.

Director Logic: Maps can now alter their layout and behavior depending on how “angry” the A.I. director is. The better the Survivors are doing, the angrier the AI Director seems to get. This allows you to base variable paths and other events on the player’s skill and current conditions.

Scavenge Mode Support! All the elements map authors need to support Scavenge in their maps. This includes game props as well as a full example in the form of Deadline 2, an updated tutorial campaign.

We have included an updated tutorial to help you get going and as always you can join the discussion on the map designer email list. What we want for New Years is to get to play your custom maps in Left 4 Dead 2.

For the best user experience and to take advantage of the new map and nav mesh formats, Left 4 Dead 1 Map Makers will want to compile Left 4 Dead 2 specific versions of their map in the new tool.

Happy Holidays,

It came out 2 hours ago, and there’s already like 10 threads on this

Three actually.


  1. Is it easier to make nav’s?
  2. Can we have custom models? that work online

Alot faster to make navs.

Haven’t seen any new tutorials on the wiki.

After I compile a map and run l4d2, the hammer windows are stuck like this


And it doesn’t run the game after


Except that one time that it did


Fuck I need to map while sober


That was in the original game, too. It was from developer commentary.


Holyshit they super-revamped the particle editor


Was about to reply saying “haha stop pulling my legs” but then I read it and found out that it’s released.

All the sky textures are purple checkered. :C

They revamped the tutorial standards map.
The first level has the car alarm crescendo which is pretty neat.

The compiler… IT IS SO WEIRD! It’s faster, though.

Yay, now we can play with the Spitter!


Eww. :barf:

WHy have they still not released the SDK for Left 4 Dead 1 (Authoring Tools yes, I know, but they have not added it to the SDK (Where you open Hammer, and select the engine/game, you know?)

Why is it that whenever I compile a map and close out of L4D2 my view ports freeze up until I restart Hammer?

What would be the point in that?

The Left 4 Dead engine is a big leap in the source engine. And also is it a big deal?