thanks ragecgi
I am using physical fog.
But the problem is that 3d noise is nothing but a bunch of pictures
so when the camera moves,a new picture apear every frame,
and thats the actual flickering.looks great only with static camera.
Same thing with cloud particles,they look flat not volumatic.
I have been through does Docs,but it didnt help since its
not a noise flicker but the texturs changing rapidly.
I never managed to get the "Use Layer" to actualy work
I hope there is a way of achiving this basic effect with maya complete
Thanks