Grain on plain surfaces

[lisux]

Hi all.

I am doing some test render using GI, via th environment light, and also trying with PBR.

So far the renders are looking good, but there is something that really bothers me. I have some rocks on a plain for the tests, the rocks renders nicely but in the plain I always get lot of noise.

Seems it is only related with plain surfaces. I remember prman used to have some settings to improve the grainy effect in plain areas, but I dont know how to fix this in Mantra.

I have attached an example image.

Thanks!

[lukeiamyourfather]

Try increasing the minimum and maximum ray samples on the Mantra output driver.

[lisux]

Try increasing the minimum and maximum ray samples on the Mantra output driver.

Thanks lukeiamyourfather.

Well this is brute force, what I want to know is why plain surfaces tends to create more noise than surfaces with more detail.

[Jason]

For a smooth still image (grain sometimes is more forgivable in motion), try

• increase Pixel Samples to something like 10x10
  
• Noise Level = 0.05
  
• Min/Max Ray Samples leave around 1/9 -- the Pixel Samples should take care of it
  
• You could try photon mapping too - that will smooth out noise and allow you to sample less.
  

[lisux]

For a smooth still image (grain sometimes is more forgivable in motion), try

• increase Pixel Samples to something like 10x10
  
• Noise Level = 0.05
  
• Min/Max Ray Samples leave around 1/9 -- the Pixel Samples should take care of it
  
• You could try photon mapping too - that will smooth out noise and allow you to sample less.
  

Thanks Jason. I did it and the render is much better.

I havent use photon mapping yet with PBR.

The Irradiance cache doesnt work with PBR isn't it?