There was a posting recently in this forum, where someone had a huge smoke ring, composed of metaballs.

I went with this approach; small metaballs gradually getting larger the farther you get from the source, and also a little fainter as it rises. The @#$% part is finding a cloud texture that works...;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)