DOF-noise question

[matteo_speri]

hello, here is my latest work, after months of studying in vray.
I have a question:
in the last image I use the DOF; with foreground blur (I used EV to lock exposure)
but the edges have a lot of noise. Does it depend on render settings?
I studied a course and they use:
vray GPU mode
mode: PROGRESSIVE
render settings - noise limit = 0.005
light cache - subdivision = 1500
(only these settings to have a clean image)

but I see a lot of noise
thanks for the advices
Matteo

[Karol.Osinski]

Hi, perhaps you could try increase the max subdivs, what is the current value?

[matteo_speri]

Hi,
thanks for the support;
these are my settings, I only set the values of the red rectangles that should guarantee an image without noise (in theory)

[Karol.Osinski]

Is it Sketchup? Here in Maya I'd try increasing max subvids, but maybe in your case you can boost the Sample Limit to something like 10k and give it a try (?).

[sirio76]

matteo_speri
LC subdivisions have nothing to do with image noise. By looking at your image seems more like a denoiser issue. Vray have 3 denoiser, you should try all the options and see if you solve the issue because that kind of noise should be easily manageable.

[matteo_speri]

Hi,
thank you
is vray for 3dsmax;
i try to bring samples limit 5000 -------> 10000
and I also try to modify the denoiser
for IPR mode I use nvidia vray ai denoisers (faster)
for final render I use default vray denoiser (in the course we teach: slower but more precise)
but I try to change it and see how the noise changes

[fixeighted]

Raising the samples limit will help for dof if a denoiser won't do it well enough without sacrificng detail.
Discussion here https://forums.chaos.com/forum/v-ray...of-bokeh-noise

[sirio76]

Hi,
thank you
is vray for 3dsmax;
i try to bring samples limit 5000 -------> 10000
and I also try to modify the denoiser
for IPR mode I use nvidia vray ai denoisers (faster)
for final render I use default vray denoiser (in the course we teach: slower but more precise)
but I try to change it and see how the noise changes

Try also the Intel denoiser

[Muhammed_Hamed]

Hey matteo_speri

Something you can change about your render settings is Light Cache Subdivs, specially if you are using GPU LC in the latest 5.2 builds. Using around 3000 is recommended for interior scenes like this one here and we will make it default value at some point, this can improve rendering speed a lot up to 2x to 4x faster in my testing and it improves quality and detail
Your sampling settings are mostly fine honestly, try to use the denoiser to clean the remaining noise on DOF. Intel's or V-Ray's denoiser should do a great job here, and in the frame buffer you can mix the denoised image with original by 50% or so
If you want to clean this DOF noise in Rendering you will need very high Sample's Limit like 20,000 or 50,000 this will help, we are looking into ways to improve this at the moment without using high number of samples

Which course are you following, out of my curiosity ?

Karol.Osinski 3Ds Max doesn't use Min/Max Subdivs, it uses Samples Limit in the UI which gets converted to Max Subdivs at render time
Max Subdivs = Square root of Sample's limit + 1
So 5000 Samples Limit(default setting) are around 70 Max Subdivs and Min Subdivs is 8 always
Maya and all other integrations will swap to using Sample's Limit similar to 3Ds Max eventually

Best,
Muhammed

[matteo_speri]

Hi, thanks to everyone for the support;
i did a test, the parameters are the same, i just changed the denoiser, and nvidia to the denoisers seems to be much cleaner and no noise.
Then I use that as a denoiser (it's even faster). And I imposed subdivs 1500 ---> 3000. i am curious to set the intel denoiser, never used. I'll try it tonight.
The very professional course is 5RSW Method

[Karol.Osinski]

Hi Muhammed, I always use 3000 LC in GPU but I will ask my collegues who uses CPU to boost their LC subdivs from 1500 to 3000, I am curious if there will be any significant difference in render times.
I would also try boosting the min subdivs in CPU to 8. Though, maximum I went for was 2 in cases with small details such as fur.
8 seems same, but not very optimized value in most cases, am I wrong to think that?

I hope you guys make sure to Sample Limit in documentation once you update the UI in other softwares, as many of us are used to Max subdivs at this point and we know what values works well in various scenarios.
There are no min subdivs in GPU, I guess they are always at 8 too, correct?

regards,
Karol

[Karol.Osinski]

Hi, thanks to everyone for the support;
i did a test, the parameters are the same, i just changed the denoiser, and nvidia to the denoisers seems to be much cleaner and no noise.
Then I use that as a denoiser (it's even faster). And I imposed subdivs 1500 ---> 3000. i am curious to set the intel denoiser, never used. I'll try it tonight.
The very professional course is 5RSW Method

Damn, Nvidia is killing it with their AI denoising solutions nowadays. It is especially visible in video games with their DLSS and DLDSR methods to upscale / downscale images.
I am aware that VRay denoiser uses render elements to denoise the image thus it is suppose to be more accurate, but am I wrong to think that Nvidia AI method can be superior in many cases?

[Muhammed_Hamed]

I will ask my collegues who uses CPU to boost their LC subdivs from 1500 to 3000, I am curious if there will be any significant difference in render times.

I also have seen speed gains on CPU using 3000 LC Subdivs for interiors as well, although the difference were not as big as V-Ray GPU (talking about 2x to 4x faster in V-Ray GPU's case)
For high resolution rendering, it is recommended to up the LC Subdivs for quality and details anyways. 1500 is fine for 2k, 3000 for 4k resolution
I have been using 3000 on both engines, as I render in 4k .. Then we came across the massive speed gains on GPU

About Min Subdivs, there is no need to use 8.. it is in place now for technical reasons and will be changed soon, 1 or 2 is usually sufficient for most cases

I hope you guys make sure to Sample Limit in documentation once you update the UI in other softwares

Yes, we will update the docs accordingly and explain how this new parameter works. I have many plans for the GPU docs I hope I can get to that soon, we will get there eventually
The point of this change is that V-Ray GPU is different and people shouldn't expect Min/Max Subdivs to behave the same way between the 2 engines

Best,
Muhammed

[matteo_speri]

thanks, very interesting,
I will always use 3000 subdvs for safety; unfortunately in the courses I study the gpu section is never very developed
Matteo

[piotrus3333]

good to know. thx for the tip Muhammed_Hamed