How can I add fog using lights?

I was thinking I could use a spotlight to make a fog-like effect. It’d work like a mask, showing everything under the light, hiding everything outside the light. I know this is possible. I just don’t know how to do it.

If there’s a tutorial for this, sorry.

Version of Blender: 2.52 r29074 (optimized for sculpting)

Btw, 2.5 is so much easier to work with than any previous version. I absolutely hated Blender’s interface before, but now, I love it.

are you talking about the halo effect on a spot? not sure about the mask , but the halo will give you a “fog”

The only way halo lights give me fog is if I use them as the fog. I’m talking about a ring of fog, around the scene.

A ring of fog? Wouldn’t it be easiest to add a torus, color it black, turn on ztransparency and apply a clouds texture to transparency?
Also, look into volumetric rendering, instead of solid rendering…
I’m not sure you can do that with lights. Maybe a textured light, but that is a different matter.

g to WIP forum find the volume thread form NRK

ther eis an example we did for Fog on a scene with volume and spotlight

but do’t think this would make everyting outisde the beam very dark

the only i can suggest is with indirect lighting in 2.5 but then you vahe to apply some emit to some or most of your objectc and that would make it very dark in the scene!

good luck
salutations