Csgo SDK is available in your steam library > Tools > Counter-strike: Global Offensive SDK. (if you wanna play around with it yourself)
Only problem is because of map optimisation the tops of roofs and such areas high up won't have textures so it'll look pretty dodgy without cleaning it up.
neutral, sounds like a cool idea, dont know if it would work too well though, as changing a map like Nuke, Cobble, and adding ramps would be hard would it not? eg. would you spawn in the sky and surf down and unless you want to strafe through doors etc you would have to surf above the map, then land down run around the map etc. get me? I think the maps in surf should be made for surf, not for Casual/Comp with ramps added.
Edit: Unless you are talking about completely making a surf map that looks like Cobble/Nuke, like a remix of a song, a mashup of the two maps. (Had no other way of explaining this, I dont know lol)
I mean, im preety sure a map designer would have to make the level. Ehh really no need
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