April 14th, 2011
Credit goes to skyride for writing this tutorial.
Here's just a quick explanation on how to use different skyboxes within Team Fortress 2.
1) Get your hands on a custom skybox. FPSBanana has a pretty good selection, just remember to look in the Counter Strike: Souce section (due to how skyboxes are used, they are completely game-mod agnostic. CSS skyboxes will work in TF2 and vice-versa). For the purposes of this tutorial, I will be using a skybox from fpsbanana.com, as seen in this video:
2) Download this script and save it in the folder "SteamApps//team fortress 2/tf/materials/Skybox", its quite likely that you will need to make the folder "Skybox".
3) Now extract the .vtf and .vmt to the Skybox folder. It should now look something like this:
4) Next, run the script you downloaded earlier (NOTE: It MUST be in the Skybox folder to work correctly). First choose the map you would like to do a sky replacement on, if the map you want to use is not on the list, choose "custom/other" and enter the name of its skybox texture. This can be found by loading the map on a local server and looking at the value of the cvar "sv_skyname", for example badlands is named "sky_badlands_01". Next you will be prompted for the name of the replacement file. In this example, we have a file called desertup.vmt, therefore the name replacement is desert. After hitting enter, the script will the rename the .vmt files. The .vmt files are simply text files that point to a .vtf texture file and contain some settings on how it should be used. If you wish, these can simply be renamed manually, all the script does is rename them for you as it can very quickly become a tedious process if you are using multiple skyboxes. Your Skybox folder should now look something like this:
5) Now simply load Team Fortress 2 and the skybox should load for the relevant map. NOTE: As with all custom textures, these are subject to sv_pure rules and therefore, cannot be used on an sv_pure 2 server. Comparison: