script/plugin to simulate then render?

[Jordan]

If you are using RPM you can easily set up a sim pass and a render pass that is dependent on the sim pass (I guess you have to be using deadline too, not backburner!)
In the Script section of RPM in the render pass I just add:
for i in getclassinstances FumeFX do print i.BackBurnerSim=false
and for the Sim pass I add:
for i in getclassinstances FumeFX do print i.BackBurnerSim=true

or you can turn them all off with the top script and individually turn them on by $MyFume.BackBurnerSim=true per sim pass (if you have multiple fumes)