Need help with specular material noise

[Yan]

Hi!
I'm using a specular material with IOR 1.55 and Roughness of 0.2 because it needs to be like a blurry glass. It has Fake Shadows turned off.

I have rendered a test with 3300 samples with path tracing and I still get noise in the glass. I need to have around 9000 samples for the noise to be gone which is very much for render time considering that I need to render about 4000 frames.

Please let me know if you have any suggestion.

Here is a crop of the render: https://www.dropbox.com/s/syffn1wd8s7ar ... 7.png?dl=0
and render settings: https://www.dropbox.com/s/kcgikbm2t7pqc ... 0.png?dl=0

Thank you!

[zoppo]

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[atome451]

Hi,

Some ideas :

• Using Gaussian spectrum for the blue light texture (less noise in colored lights than with RGBSpectrum)
  Using Gaussian spectrum for the glass in Transmission (as we work with light here, i suppose it may help but i'm not sure)
  Activating Fake shadows (and Alpha shadows in Kernel)
  Verifying scale : 0,05 or 0,025 should be enough for the Roughness with a box of 50 cm. Of course it depends of the tickness of the glass.
  Be sure exposure number is near to 1,0 and adapt the lights efficiency and power to keep a right illumination (if there is not enough illumination, working with exposure will reveal noise in shadows: there is also noise on grey plastic of your render)
  Use a linear curve (with the right gamma 2,2 Windows or 1,8 MacOS) or a curve with low contrasts
  Coherent ratio to 0,3 or 0,5 by sample and Static noise activated
  To keep good performances, Diffuse depth may be set to 6 and Specular depth to 12 by sample, or 4 and 8

glass roughness.zip

A sample file

(234.09 KiB) Downloaded 197 times

[Yan]

Thank you very much for the detailed reply.

I managed to get rid of most of the noise following your indications.