I tried to port skybox textures from CSS level cs_militia (called "militia_hdr") and use it in Portal 2. Copied all the textures with GFCscape and put them in the Portal 2 skybox folder. Set default skybox texture to use in the map properties, made a test map and launched.

Sky works correctly (with the light_environment) but every time you look at it (skybox textures) all the level disappears and you can only see the sky around you. Once you look away it changes back.

Has anyone encountered this and knows a possible solution?
Thanks!

That happens because into the VMT material files there's this parameter:

$ignorez 1

Just erase it, erase that line.

In Portal, also make sure that you are using the shader "UnlitGeneric" instead of the "Sky" one.

Your typical material files should look like this:

"UnlitGeneric"
{
$basetexture "skybox/whateverFT"
$nofog 1
}

Make sure that you have all the 6 VMT files looking similar to that one (each one with its own "$basetexture" though)

Thanks a lot!