I was trying to get the effect of a sandstorm starting, so you could still see things and the sun was still visible. Once it was well under way it would be just a sand coloured fog. I did this by messing with some of the volumetric materials, like vertical swirls, altering their functions and colours, and applying them to a series of cylinders, a bit like you do rain.

It took 2 and a half hours to render - one of the longest I have had for a 640x480 in Vue 4.

BTW, does anyone know how to get the sun/moon to be round in Vue. In my renders they are always a bit elliptical.