Noise problem on VrayLighting RE

[alessandro84]

Hi, i was tryng to do some test to increase the shading quality of my render because i need cleaner reflection. So i increase the min shading rate to 80 and also raising the min samples to 32. As i espect the render is cleaner and all the pass relative to the secondary rays got less noise. Exept for the light pass that has less noise in some areas and a lot more noise in other.

I attach you the images below. Thanks
Vray 4.02

[alessandro84]

Hi, i notice now that the resolution of the image was really low. Here a new version. Sorry for the drawback .

[vlado]

V-Ray generally only cares about noise in the RGB channel and tries to get it clean with as few calculations as possible. If some render elements are noisy, you can improve them by increasing the min subdivs for the image sampler (do not increase the min shading rate, it might make things worse; there's a reason this option is hidden by default ). Another solution that works well can be to use the V-Ray denoiser and turn on the "denoise" option for those elements.

Best regards,
Vlado

[alessandro84]

Hi, Vlado and thanks for the quck reply.

The purpose of my tests is also to better understand image sampler, DMC and balance between the AA samples versus the shanding samples ( just for learning purpose ).
In this scene i need more secondary rays sample than primary. So following the documentation i take a look to the min shade rate parameter and DMC rollout. Changing this value the calculator tells me that Vray will use 32/80 secondary rays per AA. As I expected the render was a lot more clean. I just notice this " strange " thing in the lighting element so i ask .
I did not know what you explained about RGB element and other element.
This tests were done only for satisfy my curiosity and learning porpose. ( probably i need to better spend my holiday time )

For the production render ( as always ) i have used the default value for all the settings and after a first test i've just reduced the noise treshold and the render was ok with a good balance between time and quality ( obviously better than my tests eheheh ). With no need to waste time in optimization.

Also today with the new release my test is improved for free , so thanks .

[Muhammed_Hamed]

min samples of 32/min shading rate of 80 are crazy numbers..
Vray is more about ease of use when it comes to sampling. Noise threshold is probably the only slider I touch in most cases.
Try these settings, after you reset Vray tod defaults
Bucket sampler
min subdivs=1
Max subdivs=50
noise threshold=.007
min shading rate=16 (but you can also leave it at 6)
BF+LC for GI with LC subdivs of 2000
You can turn on denoiser for your render elements, it does a good job.
Using the sampler info render element will probably help you determine where the noise is coming from

[alessandro84]

Thanks for the reply and suggestions. I will try them.