Reverse smoke using particles

I have two cigarettes in my animation. At one point in the film I want the smoke to be reverse direction, going back into the cigarette, for one of them but not the other. I was wondering if there was someway of changing the baked particles to do this. The smoke from the cigarettes will be intertwining so I don’t think I can do it in two takes and super impose it… Open to suggestions. thanks

Well I found one way… I renamed one of the sets of bphy files created when baking the particles so that the frame numbers ran the other way. I used Lupas2000… It kind of works and is probably good enough for me if there are no other suggestions but you only seem to get a busts of particles and they seem to collect at what would have been the original source.

I’m pretty new in that “Bake” process. Can you explain me how to use these “bphy files”… and where these are hidden? I’ve never seen that there were any around ;P…

Blender creates a directory when you bake particles called ‘blendcache_NameOfFile’ and you get one file for every frame you bake, and one set of files for each particle emiter. I don’t know exactly how it works but the files have a name like ‘466C616D65436972636C65_000029_00.bphys’ where the 000029 is the frame number of the bake. So I used Lupas2000, a very useful file renaming programme (and free!) to name the file in reverse order and the particles sort of played back backwards… though not totally satisfactory.