Tips on designing open environments? (source)

[Jowo98]

I am currently working on a single player project for a friend in which I need to create a countryside but this is proving difficult mainly because I am having trouble making realistic/ natural looking map boundaries. There is no water on the map and cliff faces can only go on for so long does anyone have any ideas or advice on how to handle boundaries in open environments such as this?

[Nurb]

Make some billboard:ish trees and such to break up the horizon abit (but make sure you can't walk over there for close inspection). I haven't made any completely open landscapes in source, but if I did, that's what I'd do ^^

[2d-chris]

Walls, fences, rocks, cliffs, objects (cars) mine fields, trenches are the kind of thing that pop into my mind. It can be tricky closing off an environment.

[Loafie, Hero of Dreams]

Even just a steep hill with some large boulders works nicely, it doesn't have to be completely vertical (like a cliff) inorder to create a world boundary. You can back a steep hill with another displacement in the 3d skybox and a billboard environment behind that to break up the horizon like nurb said

[Sentura]

in my opinion you don't need to make hard vertical surfaces at all. what i'd do would be to make a rising slope, to make it look like a hill, and somewhere along the top i'd noclip brushes, implying that the ground is too steep to climb further. needless to say, this approach requires that your player starts at a relative depth compared to the hill; however unlike a cliff, a hill looks more natural around plain landscape