Managing cubemap reflections on glass
In my map there's a lot of glass and some of them have ugly looking reflections from cubemaps. I've been trying to place cubemaps on different locations and add more and add less cubemaps in specific locations, but without success. Is it possible to just disable the glass reflections? The cubemaps work greate on other surfaces so I do really want to have them in my map. Thanks in advance!
You can assign env_cubemaps to faces; if you haven't done this yet, it might help. Also, have you done the 'buildcubemaps' console command yet?
But most importantly, what do your reflections look like? Simply bad, or does it look like the reflections were done on Mars? Can you post a picture?
If you aren't using custom textures, where ofc you can modulate the glass reflections, you can choose some glass materials with low/non reflections.
Try for example "glassglasswindow007a_nospec.vmt"
Anyways, you should always build cubemaps. Make sure you have a copy of your map into your /portal 2/portal2_dlc2/maps folder. Make sure that you have placed some env_cubemaps entities in your map as well 
... Then run your map and type buildcubemaps on your console.
useful tools and stuff here on TWP 
[spoiler]
[/spoiler]What does "nospec" stand for?
This first image shows a ugly reflection from a distant source. Don't you agree it look terrible?
This second image shows a example of another ulgy reflection. Underneath is a pool with toxic slime, which doesn't even remind of the reflection.
And the last image shows a reflection of a indicator light. The problem here is that when the lights turn from blue to yellow, the reflection still stays as blue.
So, I have a lot of big pieces of glass in my map and I would like it to stay that way. Is there a way to get around this problem? Thanks again!
Nospec means no specular (i.e. mirror-like) reflections.
I did experiment with env_cubemap where I tried to assign the brush faces of the glass surfaces to the env_cubemap, but I didn't noticed much of a difference. Perhaps it's broken for me or I've missed something...
How do you guys handle your glass reflections? I can't be the only one with this problem, can I?
Sorry for the late reply... No, I didn't forget to build cubemaps. I didn't find a adequete solution so I changed the texture to another glass texture that doesn't reflect in the same way. Too bad but it's a compromize. Thanks for the help.