hi - got a couple general questions about what people do about birthing and killing particles when generating krakatoa particles from fumefx sims.
We’re finding that quite low res fumefx sims give nice detailed krakatoa renders, except near the source where you can see that the rather large voxels are being filled with particles. Once the voxels are released the flow shmooshes nicely and there’s no problem, but around the source you get a pixelated look. We’re finding that increasing the jitter in pflow helps, but it still looks gritty compared to how it looks away from the source. Obviously we can turn up the resolution on the fumefx grid but since we’re happy with the level of detail, and it’s simming quite fast, we’d like to find another way. Any ideas?
I must admit I am not the best source of FumeFX advice as I’ve always let other people here handle the simulation / driving PFlow particles part.
What I would suggest is dumping the PFlow particles to a PRT sequence containing both the Age and LifeSpan channels and then using a KCM on the PRT Loader to tweak the density of the particles non-linearly based on their Age/LifeSpan value. You can do this by creating two Channel Input nodes - one for Age, one for LifeSpan, converting both to Floats using ToFloat operators, dividing the two to produce a value between 0 (birth) and 1 (death) and feed that into a Curve Node to map the 0-1 range to another 0-1 range that is not linear. This way, you can map the normalized age value between 0 and 0.1 to a much lower density to match the grainy particles at the emitter, then increase it for particles with normalized age between 0.1 and, say, 0.7 and then fade them off between 0.7 and 1.0 where they die completely transparent (Density of 0). Feed the output of the Curve Node to the Output Node of the flow and set it to Density Channel. Play with the curve to see of you can get the particles to look less grainy in the beginning.
Take a look at the examples in this topic: software.primefocusworld.com/sof … rator_Node
(the article is wrong, the Curve operator was actually introduced in 1.5.1, so you should have it)