If I’m getting this right, you want to have the outside of the water not showing from the inside? If we all do that math, we know that underwater is transparent, and refrects the obve area outside of the water to make it look exactly as water would appear. Now if you really want to make it look dark underneath do the following; Make a nodraw textured func_brush, Texture bottom side with tools/toolsblack, Then compil and the water will show and refract the outside black texture, making it dark. I use commas too much. :downs:
Also if you want more effect added too it to block all light coming in, use tools/blocklight.
One more thought, since skyboxes are cordon area, they can be seen from almost anywhere on the map as long as you aren’t staring into the void. Try making a func_viscluster in that whole water area too the roof, it makes it so the game knows that all leafs can see each other, maybe it’s simply not drawing the roof and skipping right up to the skybox?
If that doesn’t work a last ditch effort could be a giant tools/hint brush.
P.s. This has never happened to me in-game, ever.