Moving skybox/floor?

[Micnax]

I've been wondering this for a while, but how do you make a map with a moving skybox or ground, like ctf_convoy? It's really fascinated me :3

 

[Acegikmo]

Either you have moving parts in the 3D skybox, or you can make a scrolling texture.

 

[TracerDX]

In convoy, its an invisible func_conveyor for the floor, to push you as if the floor is moving (though it is not). The skybox rotates in a way as to make it look like you're circling the mountain. The floor you see is actually the well-aligned skybox.