I assume this is something I've done wrong with the sky box.

I built a huge box and am building out my architecture within it. Once each of the regions of my map is enclosed, I will remove the outer box, and check for leaks.

Underneath that box, which contains all the architecture, is my skybox, about 500px away, and the sky effect works just fine.

However, I can see, floating in the sky a few bits of chaff. If I "fly" up to them to examine them, they begin to appear as the brushes of my map, and finally, I arrive at my map again.

Any advice would be greatly appreciated. This forum, and especially the tutorials, have been very helpful. -Thanks.