Now this is the dead of SK2 or 3 or even 4

[Hervé]

Check and double check this link, and you'll know this is the end of sky tracer teknology... even though they posted a special dumb tutorial.... so far behind I already cannot see it......

http://expert.ics.purdue.edu/%7Eschpokj/research/purpl/clouds/index.html

[erikals]

Wow :) That's really neat.
But don't forget about (I think his name was Oki) Oki's Sky generator. That looks promissing as well. ;) (Note, I'm not talking about Eki).

(Related, cool smoke simulation)
http://graphics.stanford.edu/~fedkiw/