what map is that guys?

This reminds me of that portal repercussions screenshot.

i luve it

no, the acid uses l4d2's updated water shader, fizzlers use a special shader. Yeah I could make a pretty convincing looking rain texture with a fizzler shader... but I'm just using numerous unlittwotexture shader materials.

I guess the one upside of using the current thing I'm using is that it works in most source engine games other than portal 2, and it's more well documented. But yeah theoretically you could use the fizzler shader and get good results too

Is it any way simmilar to the acid or fizzler textures?

aha. I was close. (pretty far, but close(another self contradictory statement by me)

5 brushes, each with a unique material, and each material has 2 textures per material as well as numerous proxies to control sporatic fading and whatnot. there's also a skydome with another scrolling 2-texture vmt to give the illusion of a moving sky, and in newer versions, a rain particle system.

So, it's scrolling textures with alpha layers on 3 dimentional brushes?

it's more complex than that...

Scrolling textures?