How does TF2Maps make their 3D Skyboxes?

[Shaeam]

I've got a rather... Strange question; but one that drives me to ask it. How do you guys make your 3D Skyboxes? I've barely messed with the concept; so i'm relatively new and looking for some advice.
Now -- I know HOW to make them -- i'm merely asking how you guys make yours. For example, do you build the skybox around the map then drag it aside and scale it down; or do you make a already scaled down area of skybox and work from that?
I'm incredibly curious on which method is considered the best or most efficient. To be honest; i'm not even sure how valve does theirs.
Any insight on this topic would be appreciated.

 

[Egan]

I learned by watching TopHattWaffle's video on the subject. Also if there is any difference in lighting between the 3d skybox and the edge of your map you can try tossing in some blocklight in the 3dskybox where walls in the actual map are to emulate the shadows and stuff. (Although generally it's best to not let the player get in close enough to scan for the edge of the map; use railings and shit).

 

[Valkyrie]

I do the same as Egan, its a lot easier