Flickering on the grass

[51R]

Dear Coronians!
My main problem shown in the attached video, is the noisy visualisation of the Grass infront of the house.
The Grass is created in geometry and then Instanced manually over the Ground.
I tried different Values of the sampling balance and Speed/Accuracy balance, Denoising tool, Image Filter and so on, but didnt got any better result than with the standard settings that were provided by the bought scene.

The Still render looks great, but when getting into animation "CameraMovement" it doesnt, I cant send it like this to my client.

I have now a Rendertime per frame of 10:30 minutes and that is huge, for 1 minute of film.
My sytem is not the perfect one for a cpu render, but the Ryzen theardripper 1920x has a good banchmark rate + I have 64GB of Ram and a 1080TI as GPU.

I really need your advice how to solve that?
What should I do?

Kindly 51R

[rowmanns]

Hi,

Are you using the UHD cache? If so, do you have "Animation" ticked in the UHD cache settings?

Rowan

[51R]

Hy Rowan!
Thanks for the fast reply!
Yes Im using the UHD, and yes was using the Animation preset with a precision of 1 and Do Previz ON.

Bests

[romullus]

To me it doesn't look like GI flickering, but rather noise "boiling". Maybe try to lock noise pattern and render small sample to see if if the flickering will be less noticeable?

[51R]

the lock sampling pattern was already checked ON ;)

[51R]

Im getting a similar Problem with the Lights in the Mainroom, the Luminance Emission is flickering aswell...

Thought about it that it will be tricky to solve that!

But for now thanks for the replies!

[GeorgeK]

the lock sampling pattern was already checked ON ;)

Are you rendering with time limit or noise limit per frame? How much noise per frame you are getting?

Is AOmat applied on the ground or the grass, does the grass have reflectivity with low amounts of glossiness?

Please let me know.

[51R]

Hy George,

I Have a Time Limit set onto 10 minutes, usually getting a Noise Level of 5-9%, but not sure how to see it after the render is complete.
The Grass material had a Diffuse channel and a translucency channel on.

I started a render half res and with 5 min time limit with the translucency off to test for now.

Didnt had any AOChannel/Shader activated for now, should I?
the Texture in the Diffuse Channel is integrated in a Filter Shader. with small colorcorrection on to it, Hue 15°, Sat -1% and Gamma 1.28

Thx Mate

[GeorgeK]

Hy George,

I Have a Time Limit set onto 10 minutes, usually getting a Noise Level of 5-9%, but not sure how to see it after the render is complete.
The Grass material had a Diffuse channel and a translucency channel on.

I started a render half res and with 5 min time limit with the translucency off to test for now.

Didnt had any AOChannel/Shader activated for now, should I?
the Texture in the Diffuse Channel is integrated in a Filter Shader. with small colorcorrection on to it, Hue 15°, Sat -1% and Gamma 1.28

Thx Mate

Ideally, I would suggest you go for a fixed 4.5% -5.0% or 5.5% noise limit / frame, it might take longer to finish but I believe most of the noise will be cleared. Sometimes with grass noise the offender is reflectivity and glossiness due to firefly noise, which can be resolved by highlight clamping but I don't think that's the case with you.

Regarding translucency I doubt again that it would be the reason behind the noise, but it's  doesn't hurt to test it.

Lastly is there displacement on the ground?

[51R]

Will check when done with some frames for translucency!

The noise level of the current render was 6.28%
Will make next render test with noise limit ;)

So yeah the ground itself has a displacement and bump map onto it + reflection and Diffuse. (Maybe the reflective layer is causing some problems?)
the Grass and instances itself are placed manually and where not scattered and so dont have anything to do with the ground itself.

[GeorgeK]

Will check when done with some frames for translucency!

The noise level of the current render was 6.28%
Will make next render test with noise limit ;)

So yeah the ground itself has a displacement and bump map onto it + reflection and Diffuse. (Maybe the reflective layer is causing some problems?)
the Grass and instances itself are placed manually and where not scattered and so dont have anything to do with the ground itself.

To do this faster, set your rendering as view-port selection and select only the grass and the ground. You will still be able to tell in the end if there is noise, you can later then simply overlap the footage on your initial footage you already have.

Regarding the ground, 2.5D displacement has some minor issues that still need ironing out, could play a role in this but really hard to tell. My initial suggestion still stands, when having to do with really small details it's better to go with low noise limit.

Please let me know how it goes.

[51R]

Thx George and hole Corona Team!

Will make some tests with all this info I got! And asap let you know how things are going!

Again Thanks a lot and wow, really amazing support!
Bests
51R

[51R]

Good monday dear coronians!

So I tried a lot with all the good advices listed here, there where some improvements in the flicker but really it always remained quite the same! Then I tried the setting of the displacement settings and changed it to world size and I got a much better improvement, raised it to 2cm and its almost gone, any bigger value didnt made any improvement... dont know why the displacement setting has something to do with that.

But at least i need to render also a IDmask for the grass plane and add a denoiser in a post programm...
I was hoping to not to have to do that, I am a bit disappointed of this huge problems in animations with this renderer, for stills and big poster renders it is amazing!
Hope to get that project done 😬

If someone has some other tips would be much appreciable!

[GeorgeK]

Good monday dear coronians!

So I tried a lot with all the good advices listed here, there where some improvements in the flicker but really it always remained quite the same! Then I tried the setting of the displacement settings and changed it to world size and I got a much better improvement, raised it to 2cm and its almost gone, any bigger value didnt made any improvement... dont know why the displacement setting has something to do with that.

But at least i need to render also a IDmask for the grass plane and add a denoiser in a post programm...
I was hoping to not to have to do that, I am a bit disappointed of this huge problems in animations with this renderer, for stills and big poster renders it is amazing!
Hope to get that project done 😬

If someone has some other tips would be much appreciable!

So it was the displacement, hmm interesting. Can you please share just the displacement material along with it's plane geometry without textures and  please share what did you use for Grass, scatter or something else?

Thanks.

[51R]

So here I uploaded the scene
https://we.tl/t-xP7MZvr3gE
with the ground and the grass, I didnt send the hdri, they are quite simple hdrs from hdrihaven.
I was also wondering, cause It is really strange. I dont have any setted displacement.. But it was a improvement with the flickering on to the grass. maybe i am doing something really wrong, but I need to finish this piece.

I didnt uzse any scattering, cause the scene was build like this with instanced objects of the grass. But maybe that could be the problem, would be lovely to hear your expert opinion

Bests