Flickering in FumeFX then using Multiple Scattering

[circusboy]

hey guys. i have some issues with fumefx these days which i dont get solved so far. as soon as render with multiple scattering i get some bad flickering in the liquid - even if its moving really slow. i tried to lower the max-depth and also tried to increase the radius (i usually have my strength for the specific channel at around 0.15) but it doesnt seem to work.

now to the question: has anybody of you any solution for that already? or is it just meant to flicker what i cant really imagine tbh. would be great if you can help me out.

thanks
subb
When you say 'flicker' do you mean
a) across the entire effect?
b) Or just subtle random popping on different parts of the smoke?

if a) Try without fluid mapping-if solved increase the Simulation quality to 6 or more and turn on the fluid mapping.
If still no go there is also an issue with protection scheme which seems to trigger occasionaly -even for legit users. I've heard if you save your scene when ready to render, exit max reload and render first thing it might go away. Also may not bother a back-burner render.

for b) we just seemed to solve this issue (for our production) by taking the Maximum Depth from 5 (default) to 2 which you say you've tried already...
Whats your smoke opacity set to?

[subbz2k]

hi. thx for the answer.

in this particular example it isnt the smoke that i render. i just used the channel shader to render the fire with shadows. the density is around 2 and the light also uses the new ab shadow from afterburn with a shadow size of 256.

i've uploaded a quick example of what i mean. it does flicker pretty much all the time as can be seen here:
http://www.liquidpath.de/misc/ffx_channel.avi

also i have the quality always up to 10 in the simulation tab and use max iterations of around 300. so i dont think that there is too less overall quality. i will give it a try without the fluid mapping. it may be that the noise map is too much detailed and that causes the flickering but i cannot imagine this because: it isnt sooo detailed at all.

btw i already noted that this flickering happens if i turn off multiple scattering also. so this must be a problem with the light itself. but i really dunno there to search for it :-/

do you have any other ideas?
subb

[circusboy]

Kinda looks like the license scheme protection issue.
Do you have backburner setup?

Here is another clue-if your alpha is effected its probably that license bug.
Issues just from scattering (like what I saw here) did not effect the alphas...

[subbz2k]

no i dont have a backburner setup. i have backburner installed of course but i dont use it (i have only one pc). and whats that licence scheme issue you speak of? never heard of that. what is that exactly and how can i come around this?

btw i do a render of my alpha channel now. if this is what you meant with the alpha i will see if it flickers too in just a minute. will let you know as soon as it finished rendering.

[edit] ok it just finished rendering and i checked the alpha and it looks great! no flickering, nothing. it looks nice and smooth. so i guess this is not the problem, or is this not what you meant?

[circusboy]

Just check for other issues regarding flickers here.
It comes up a few times in the FFX sticky -basically a machine that doesn't have a history of the scene or fume fx open for long periods of time does't seem to do the render-flicker bug.
Thats why a dedicated farm of back-burner machines seem to render fine-they have no other history with the scene. Can you render this on any other machine anywhere?

Urban legend has it its there to spot non-legit copies of fumefx.
However the fact that your alpha is ok maybe the scattering as you guessed.
rebuild lighting?
talk to the developer?
re-install max/fume?

shrug-this is all I know...

[subbz2k]

well no i have no other machine to render on. as said, i only have one computer and i dont want to install my fumefx copy on the pc of a friend or so (i dunno if this even works because of the licence). but good to know what this licence issue is.

well, in the meantime i rendered without the map and had no issues with flickering anymore. but - as a consequence - the fluid doesnt look so good now. will try this with a not so much detailed noise map and hope that i get this solved. otherwise i would follow your hint and talk to sitni sati. but: if you or anyone else (maybe allan mckay? he should be quite familiar with that) has another idea bout that i would really appreciate to hear it.

anyway: thanks so far. will do another post if i run into that issue with a less detailed map again.

cheers
subb

[subbz2k]

ok i completed another test with a less detailed noise map and multiple scattering on. this time it seems to work as it can be seen in the following clip:

http://www.liquidpath.de/misc/burning_blue.avi

instead of using only the data channel i used the standard shader with both channels again in this test. and although there're still some little inconsistences in the shading (at least as far as i see, correct me if it isnt) i cant see any significant or even any flickering at all. in this example i have the noise map applied to the actual smoke.

and at this point it becomes pretty obvious for me what i've done wrong. in the example before i only used the data channel for the fire itself. and i tweaked it with a noise map that much so that it almost looked like smoke. but still it was the fire and as such it IS actually a light generator itself and it seems that if you have a light in your sim, fumefx threads the fire as a light distributor which in fact is just realistic. and at this point its quite normal that it flickered like hell since the map was applied to the fire and the motion also affects the light distribution.

i will continue to sim this example above though it already takes almost a minute to render one frame. but as it seems it works now.

thanks again for your help!
subb

[circusboy]

Kewlness! Looks a lot better for sure.

Just in case it helps. Just reading a bit more FFX sticky and somebody else solved it (for them) when they rendered .png and .rpf (instead of .tga).

Meanwhile I hadn't seen the like since we started outputting .exr as defacto (for more range).
So if your rendering tga's-maybe try another format for grins?!

glad you've got somewhere in any case.

[CapitanRed]

don't use ab shadowmap if there is no ab in it. why would you???
If you use it, make sure the map res is big enough. I had issues with ab and ab-shadowmap. I did flicker exactly as you explained(in your avi's i see only green ;) ). increasing the mapsize solved it.

there's a thread on cg-fuids, a guy had flickers with fume when having two different maps for smoke and fire. and when the timestep is lower than 1, he had to increase the map framerate (if i remember right).

btw. increasing the quality to 10 can make your sim very slow. quality is the multiplyer of the maximum iterations. and some experienced people i wrote that there's no visible difference ;)

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.