When I load old maps, everything loads fine, and I got a 3d camera view, but when I make a new map it's completely black (yes I have built stuff

)
I build a highly decorative room in the dead center of the map, without moving the view once. Hollow and everything, tried moving around, and used 1 and 2 to shorten/lengthen the viewing distance, still black.
(mapping for HL2DM)