Using the 'fogdome' in game will likely suffice, for those who are interested in doing so.

perhaps your monitor has more gamma or brightness than mine; it's obviously yellow. the texture could have been better, but i enabled anti-aliasing which made it smoother. the "variance" is actually shadows. i can not add more noise to the "sand" in the air because it isnt actually clouds. it works kind of like the fog in sauer.

well good try at least :)

by that principle you should also make fog entities

Things are not that easy... :/
All i can say is: 100% not possibble for me. I would need to know OpenGL coding hardly.

I don't know about entities, but GL allows you to set the fog start, end, and density values, which can be used to more finely control the fog.
After skimming the source, it seems GL_FOG_START and GL_FOG_END are used, while GL_FOG_DENSITY is unused.
The part you want is setfog() in engine/rendergl.cpp, and blendfog() above that. (Note that I'm using SVN for my reference, not Trooper edition.)
It actually seems that you could trivially set up these values with VARR() or something and have them accessible from Cubescript.

i didnt know sand would make such a big conversation.

Yes, but i still would need to set position of the fog.
"Fogged box" would need 4 vectors which is not big problem for me (linked vector ents?) but implementing it into fog...

what do you mean implementing it into the fog? we're talking about a standalone entity, completely out of the normal fog system. some things i can think of is

1st attrib. radious
2nd attrib. % from center to edge of fog where is gradually fading
3rd attrib. % density of overall fog entity
4th attrib. color

more people talk about this than the skybox node you're talking on :(

Make a forum topic to discuss this. This thread is for penguin's skybox.

The center of the fog is the player, of course! And then you just have the start and end distances.
I'm not talking about entities, I'm talking about extending the existing fog (with Cubescript variables). (I said that in my other post, but I guess it wasn't prominent enough.)

If you wanted to do localized fog, though, you probably would want to use an entity. An area particle effect would probably work fine. Take a partially transparent (~20%?) round smoke ball image and render a bunch over an area. Rotate the images and fade in and out. Maybe move around (on XY axes, maybe a little Z) too.
You could even drop the world fog way down while you're inside, to really limit visibility. (Hey, do I smell smoke grenades? :D) But that is getting a little complicated.

Anyway, Windecker is right. You should probably split this off into its own thread.