Some questions ;]
Hi all. I have some questions about portal 2.
How to create water?
How to create working info_overlays(http://img685.imageshack.us/img685/2246/64151517.png)?
here are a few tutorials I used when getting into p2 mapping initially: http://wiki.p2mods.com/index.php?title=Tutorials
They have a good writeup on how to create the water hazard. I have a few projects with working overlays, so I'll go take a look at what I did to make them work the way I wanted
can you say me how to create working overlays?
If you use the tool on the bottom left (a cube with green square on top) it should work?
.... 
It is probably made with texture_toggle and logic_relay?
The Valve Developer Wiki has a full tutorial for creating working indicator lights for Portal 1.
http://developer.valvesoftware.com/wiki ... tor_lights
Perhaps I'm putting my foot in my mouth here since I haven't created these in Portal 2 yet, but I believe the process should be pretty much the same?
I can confirm that the process is the same, though I struggled a lot with that tutorial (and others) yesterday trying to understand how they work. In the end what worked was not trying to understand it and just doing it :S
(What I didn't understand was how env_texturetoggle worked; I kept looking for a place to setup exactly what textures I wanted to swap between, but as it turned out the indicator light textures are simply magic and just happen to understand the SetTextureIndex thingy.)
I believe they are basically animated textures that don't play. When you use the SetTextureIndex you are just changing it to that frame in the animation.
Ah that's interesting. How do you know if a texture supports animations or not? Can you tell from the texture browser?
I'm not sure if you can tell from the texture browser but if you open the material's .VMT file you will be able to see all the animation info.