This is a mesh with a volume shader. After year i have anderstood that cycles can render multi-scattering volume … In any other render engine it is checkbox in material settings, but in cycles this option located in render settings (light pass)… i need more thoroughly read the documentation . Any way… Cycles gives very beautiful smoke.
Beautiful. It looks like you can physically touch it.
That looks very tasty, nice job. You might want to also check out this setup by HJ Hornbeck on Blendswap. https://www.blendswap.com/blend/23952