http://img402.imageshack.us/img402/1750/portal2badlight.jpg

But underneath the brush the lighting is fine.

http://img585.imageshack.us/img585/6917/portal2goodlight.jpg

What is causing this problem.

If so remove it NEVER EVER EVER use textures with _vertex in their name!!!
use their normal counterparts, vertex texures = bad lighting

Second thing: Lighting is calculated from the start position of a brush in a map, so if that brush is hidden on map spawn and shows up later it's lighting will be off.

If that's the case, start it enabled, disable it on map spawn and re-enable it when you need to.

Haggis wrote:
Im going to have to think of something else than those moving platforms, i just cant get the light right. I even tried a piston that just moved in a straight line, but its as you said lpfraky, what ever is hidden will not show up when seen.

Have you considered that it starts in the position you want it to end up (so it gets light) and as soon as the map starts move it back?
The player will spent the first ~5 seconds getting down from the elevator, through the elevator door, plenty of time to hide it again

Lpfreaky90, your a genius. That worked a treat