For the record, I don’t mean editing the sky with the Sky Editor, I already know how to handle that. I mean actually switching the skybox map temporarily, which, yes, could be done before.
In GMod 12, I could change the skybox by inserting " sv_skyname <SKY TEXTURE>" in the console, quicksaving and then loading the save. In GMod 13, trying the same method gave me no results, probably because the saving system is different now.
Is there any other way of switching the sky map that actually works in 13? I’d be much appreciated if anybody could help.