Hey,

I have created a smoke sim from a particle system for a train locomotive and so far I am pretty pleased with the result except for one problem.

The problem is that I want the density of the smoke to die off gradually after the particle has been alive for around 100 frames. I wasnt sure if I was to add an age expression or node to the POP network to fade out the opacity of the particles. I also have a volume visualisation, I was thinking of adding an if expression to the density scale to fade out the density over time?

Thanks for looking.