Infinite background

[Box]

So I would like to create a map that has effect on upward beyond the cliff but with water instead. I really have no idea how to do this so if someone could help that would be nice. Here's a example of what I meant in case I didn't word it correctly:

 

[radarhead]

Ah, you seem like you want to create a 3D Skybox! That link should give you an overview of what it is and how to set one up.

 

[RodionJenga]

I believe the fuzzy, fading into the distance effect is done with an env_fog_controler set to the same color as the 2d skybox's horizon.