A look at the basics of smoke simulations. It is worth looking at the video series on volumes before doing the smoke tutorials.  This first part looks at setting up a simulation, the fields involved, how to visualise them. It also looks at temperature and bouyancy as well as vortex confinement. Some of the example files are at NOTE: With Houdini 11 the method of sourcing smoke has changed, using the smoke from volume shelf tool produces the same result as the old shelf tool. See the Sourcing in H11 Video