I've got a stream running through the middle of my map, and it's winding and all, so I decided I'd make it out of several small brushes to optimize and keep the surface area of the water that isn't seen by the player as small as possible.

This is good and fine and all until I have to build cubemaps. It becomes pretty obvious which brush is which as they end up being lit differently... I've been minimal with my cubemaps, placing one over each brush, and then I tried placing several more with cubemaps over where two brushes meet, but both resulted in the weird lighting. Now I'm pondering whether I should use any cubemaps over the water at all (which seems to go against the general rule of thumb). Anyone else have a problem with this?

Not sure if this will make a difference but did you go into the cubemaps properties and select the water surface using the brush faces/pick tool? Use one cubemap for each water brush selecting the top surface with the pick tool and that should be fine.

I didn't do it like that necessarily. I used the entity tool and with env_cubemap selected I cliked on the face of the water brush I wanted it on in the 3D View. Then, using ctrl+m I moved it up 16 units. Does it make a difference if done the other way?

The cubemaps ARE working. The problem is that it's possible to see the border between one water brush and the other because their reflections of the world around them are slightly different.

Originally posted by ok comp
I didn't do it like that necessarily. I used the entity tool and with env_cubemap selected I cliked on the face of the water brush I wanted it on in the 3D View. Then, using ctrl+m I moved it up 16 units. Does it make a difference if done the other way?

The cubemaps ARE working. The problem is that it's possible to see the border between one water brush and the other because their reflections of the world around them are slightly different.

try moving them closer together,near the edge that the two brushes share,this would make the two view more similar

Does the brush only adopt one cubemap though? I can see the idea behind having the cubemaps around the border, and I tried that on my last compile and it still didn't look right.

have a read through this:
http://developer.valvesoftware.com/wiki/Cubemaps

Because this is what i found interesting:

"Because surfaces must approximate their surroundings via cubemaps, using too many cubemaps in a small area can cause noticeable visual discontinuities when moving around. For areas of high reflectivity, it is generally more correct to place one cubemap in the center of the surface and no more. This avoids seams or popping as the view changes."

But read it all it's got good info on optimizing cubemap placement and such.

P.S. Also try changing the 'cubemap size' in the properties, try with it set at default first then play aorund with the other sizes.

i accidently double-posted :(.