Would you mind sharing how you did the amazingly good smoke in that image?

It is very well done.  I have recently been unable to make decent smoke / clouds.  I looked at several of my older images and can not duplicate the effects I once made.  I lost the BR5 files to a disk failure.  So I can't load those back up.

I remembered vaguely reading the Brycetech tutorial, and tried to follow it... but I hit what seems to be a bug in 5.5c with volumetrics.  The spheres are not touching each other but are still erasing bits if each other.

I posted on the Bryce forums at Daz and got two helpful replies,  but neither seem to produce the results I once got which were similar to yours.

http://forum.daz3d.com/viewtopic.php?t=45700