fumefx 2.0 post processing flickering?


#1

I have some.fumefx post processing flickering going on in my renders. I scaled down the retming from 1.0 to .3 in my fumefx post processing. the motion looks good, however i am getting weird flickring in my renders. I think this is due to the post processing calculation. Anyone know a fix?

http://www.ruoyuli.com/wips/shot_3_environment_1.mov
right click to save
thanks in advance


#2

I ran into this problem during “Alice in Wonderland” back in December. It appears that there’s a limit to how much you can slow down the fluid with post-processing before it starts to artifact. In testing I found that I couldn’t push it below 0.25 however it sounds like you’re above this. The moat mist was done in a 3 stage process of running a coarse grid simulation, then a wavelet sim on a fine grid and finally retimed to 25% of the original speed. Perhaps running wavelet turbulence smoothed out the density values during the retime?


#3

hey dude,
thanks for the suggestion. Before retime in fumefx. what was the most common way to slow down the movement of a large scale smoke/cloud? Curious as i have seen some demos done by another brandon. :smiley: any feedback will be appreciated


#4

Before Fume 2.0 it was mostly a matter of playing with Velocity Dampening and Time Scale. In general, it’s good to be working with accurate scene scale when doing simulations in the first place.


#5

I don’t suppose anyone has a workaround-or confirmation of a cause for this?
So far i can’t avoid the flickers with retimes. Two different and unrelated test scenes both seem to do it. One was fire and smoke-the other smoke only (large scale style).
I am using FumeFX 2.1a.
Tried going through wavelet-but it didn’t help. I am only retiming by .5…
Seems like a bug really.


#6

You should contact FumeFx support then.


#7

Yes -ya just know they seem to be offline since Friday. Neither myself nor a colleague can login. Is it us(fire wall)-can anyone confirm they can login to the afterworks web today?


#8

One thing that can save you in a pinch is to take your camera and geometry and speed everything up x number of times.

Render out the frames then use o-flow or twixtor or whatever to re-time the smoke to the original frame count.

Often smoke works surprisingly well because a little bit of error in the warping is not usually noticeable.

This is really only a trick you would want to bust out if you have a deadline and no other options.


#9

ahh twixtor. i love that plugin. it can be forgiving if the smoke is engulfing the view. But if there are alot of high details stuff. twixtor can generate unwanted artifacts. I tried retiming again with fumefx, played around with the lighting and shading and was about to get rid of the flickering. i think the density of the smoke can contribute to the flickering. which could be a result of the mapping for the smoke looping over a period of time. If one lowers the density i think it becomes less visible.


#10

Its very inconsistant. I’ve got one shot-just smoke where the entire thing flickers.
I’ve got another where just a core of the fire seems to do it-if I hide that fire from rendering
that one’s smoke is flicker free.

I’m of the opinion currently that i will test PP early in my setups -when everything is ‘about’ right just tweaking needed. If if shows up i just won’t try it again for that shot. nada.

I’ve gotten pretty used to using time scale for slowmotion…


#11

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