fireflies

[Vividus]

Hello There,

we are starting to use 3.4 and get used to the "new"way of dealing with min shading rate and the automatic option of dealing with subdivisions for lights and materials

This is my first interior at high res with this new approach and I am experimenting an issue that I am not able to solve by myself so really hope if someone can help me out as this is a production project for the company

I am experiemnting tons of fireflies on reflective materials but I cannot get rid of those by increasing the min and max subdivision on anti aliasing

My render time is 22h at 6000px wide which it is a lot and it seem that the noise and quality overall is pretty good however those fireflies are killing me

Attaced you guys can see what i am talking about

some tech aspects

i am using 3d max 2017, vray 3.4 ,vray physical camera, vray sun and two light portals for the windows and vray spheres for the artificial lights

Vray settings: BF+LC set as default but the only options modified are:

Bucket image sampler
min subs: 12
max subs 36
noise thresholde 0.005
min shading rate 6

max ray intens 20 and if I go lower does not do anything

probabilistic lights 20

LC : 1500 subdivs
sample size 0.01
rest as default

I hope you guys can help me out thank you in advance

[thanulee]

Im not familiar with this method of sampling, but for fireflies, reducing max ray intensity in global switches might help. Disabling reflective gi caustics might also help. If else fail, try subpixel mapping + clamp output, though those are depreciated in 3.4. Sometimes i also noticed that GGX produced artifacts along with bump, though seems to be fixed in 3.4. Mmm cant think of anything else, just wanna tell u that having noise in ur raw reflection or reflection pass, is something that most of the times doesnt affect ur beauty.
Yes 22h seem excessively high in my opinion, but i cant give u any help on the sampling approach ur choosing. Good luck!

edit: min samples 12 is wayyy overkill even if u had dof in there.

[Morbid Angel]

hmm I don't see fireflies in the rgb or reflection pass, only in raw reflection, but you don't really have the use for raw reflection do you?

min 12 subdivs is overkill for sure. Usually 2 is enough. If you have speckle in the highlites it means something is not getting enough rays. For example it can occur if you have a highres hdr with sun as a dot (very bright).

[Vividus]

thanulee, how do you seet up a scene? are you still playing with lights subdivs and materials subdivs?

Morbid Angel's, i do not need the raw reflection but i always take a look at it to see you my reflection sampling is behaving and as you can see if it pretty dirty which it does not usually happens but i cannot get it cleaner with the automated sampling

I only have a sun set to 1

[Morbid Angel]

can you post this scene so we can have a look?

[Vividus]

My company does not allow me to share the scene with everyone but i can send you a private link to your email if you give me an email adress

That being said i am absolutely williing to share the scene to whoever want to help

[DaveKW]

We've had issues with noisy raw reflections but other wise clean passes when we had embree enabled.

[Vividus]

Hi Derek,

thanks for the answer, I have embree on

[thanulee]

thanulee, how do you seet up a scene? are you still playing with lights subdivs and materials subdivs?

I target samples with another way more "oldschool" but with much finer control. Not easy to explain u over few words though. I rarely give my mats or lights more than 8 though, cause since vray 3.2 this is not needed. And i rarely go above 1-8 subvs as well. As i told u though many parameters are related to fireflies. As morbid said, hdr causes that also, but u got a sun here. Might be many things, needs some investigation.
Send me a link as well if u want at thanulee@yahoo.gr, but i cant promise i can look on it before the weekend.

[benb32]

Vividus, Vlado has always shown much interest in scenes that behave poorly with the new sampling from ver 3.4. Sending such scenes to chaos support is really helpful to us all. Improvements have been made across the board. A few difficult to clean images have been attributed to a variety of factors, unusual changes from the defaults, material setups with unrealistically high values or non vray materials from important geometry... if you want a definitive answer send it to support

[Vividus]

absolutely benb32 I contacted them a few days ago but i received no answer

I will contact them again

Thanks

[Miro]

@Vividus A person from our team replied to your ticket on the 31st. Did you receive it?

[Vividus]

Hi Miroslav,

yes he did and i have been trying to figure out the issue as I had to deliver the project last week but I could not solved the issue 100%

I kind of "fix" it but decreasing the lights intensity on some areas but even currently being at 400 the white noise on reflective metals are still there

Morbid angel helped me out bu trying himself the same scene on vray 3.5 and the issue disappeared however I tried the same scene and the white spots appeared again

I am going to reply to the person on the technical department then

thanks for the heads up

[M.Max]

Please update the thread here if you find any solution in future as I faced this problem many times without finding good solution for it yet

Thanks ,

[Miro]

I am going to reply to the person on the technical department then

Please do. Thanks

@M.Max Will make a note of it and we'll post here as well.