Is that some sort of global noise at the spheres opacity?
Though I don't know if a local one would have been better,
since this is a rly nice result.
here, some new stuff for you ppl:
http://the-5.deviantart.com/art/longsword-2-133382391 <-- have been working on realistic (or at least better looking) materials lately...
http://the-5.deviantart.com/art/Forged-axe-133383349 <-- ... and on simple "special effects" that dont boost rendering time
http://the-5.deviantart.com/art/Black-City-133383794
offtopic:
What was that stupid robbery stuff during my absence? Lost 3k...
It's not noise, it's a clouds/ fractal procedural in 3d space, combined with volumetric spheres to create this effect.
Well sorry, in max this kind of procedual map is called "noise".
But since that clouds procedual is aligned to global axes (or the cameras axis) and not to the objects relative coordinates you can hardly see that the spheres are actualy volumetric.