It is possible to forge outside the boundaries?, there are a few interesting bsckgrounds out of the boundaries.
Unfortunately, (to my knowledge) there's no way to remove the soft kill boundaries littering all of the interesting parts of the map. To be fair however, the only reason those places are interesting is because we can't get to them. I discovered that you can spawn objects into said boundaries and snap their coordinates (you cannot push them further into the kill zone however) where they can sit purposeless. Make a completely indoor map with the waterfall in it perhaps? Edit: Hippie did something that made this post completely useless. Instead of a soft kill zone, for Forgeworld's "top" a Soft Ceiling is used, which can be penetrated.
Yes it is possible I have played a map were he had teleporters that took you out side the map however it still had the soft kill on it so it wasn't playable, but it was kinda cool.
Somewhere, probably here, I found a map file with an "underwater" area opened up. Its nice but I cant think how to use it (you cant see 5 feet in front of you when underwater!)
I've been thinking of building a map which uses the invisible barrier, then I don't have to use kill zones or make a ceiling which will block the nice view of the sky.. I haven't seen anyone make a playable map outside the map and I don't see much reason to. You'd just have a big empty space, much like the one next to the Canyon, but smaller...
The trees and other terrain in the places where you can't go would be pretty low quality, because they aren't meant to be seen that close