I imported gmod maps to sfm but....

[bourbon.sternum]

no skybox... please help

[Wawoul]

You could try edit it with sdk hammer or these guys then to convert maps for you
http://sfmbox.com/convert-a-map-for-source-filmmaker/

[psi onix]

have you tried using a new one by just inputing one of Valve's skyboxs in the console? I have previously done that with a Gmod map that loaded with no skybox, worked pretty good.

Except the sky looked really bad when i rendered it. I did not troubleshoot that issue to see if it was a problem with the skybox i ended up choosing or something in the render settings because i have scrapped that project anyway.