- the smoke that rises from the tip (end) of the cigarette as it burns
- the smoke that rises from the filter of the cigarette after an inhalation (most likely this is the smoke that has been pulled through the cigarette but didn't get inhaled)
- the smoke that the smoker blows out
I started experimenting with XSI particles and then adding effects in the fx tree. This could work well if I could pin the start of the particles to the end of the cigarette (in theory this is possible using the tracker, but I'm using XSI 4.2 and the fxtree tracker crashes XSI... This is fixed in 5.0 but I'm a bit weary of upgrading at this point in production).
Currently I'm experimenting with the volume shader for cigarette smoke. You can get a good head start on this by using Holger Schonberger's preset downloadable from http://www.edharriss.com/shaders/shaders.htm. A small tip about using the volume shader technique - the smoke rises straight up until it hits the center of the object - so to control when the turbulence starts in the smoke, edit the center of the object.
For the exhaling of the smoke, I'm currently experimenting with the smoke explosion particleop.