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Hi there - I am rendering a scene with a background forest and render sequence is very noise in the shadow area.

After reading some threads I increased my env light to 512 sample ( no hdri uses) and my distance light to 256.

this is my path_tracer setting to minimize noise but my render goes for 10mins(noisy) to 44 mins per frame to fixe noise in HD render.
the only difference is Subsample Quality and Shading Oversampling are at 10%

AA:9sp
Refinement Max Sample Count: 450spp
Anti aliasing filter: Gaussian
Subsample Quality:10%
Shading Oversampling: 10%
Material Sample: 256 spp
Glossy Reflection sampling Multiplier :3X

Primitive Count: 17338Billlions
Point Count 7.220

Assets made in speedtree
Disabled all opacity maps on leaf to save render time

44mins to render a noise free frame on a Threadripper 3970x seem crazy to me, any pointer?
thanks

Hi,

Did you check the AOVs to see where the noise is coming from?
https://www.isotropix.com/learn/tutoria ... asterclass

Thank you Sam, your video is amazing. I will go back to my scene to output more Aov's and the Lights ones also.
I will report later if I still have issues after applying what I learn from your video.

Glad you like it. I made it specifically for that types of problems. I hope it will help.

Obviously this scene with a lot of trees requires a large AA to sample. I usually use 64 or more to get rid of the leaf jitter。And I didn't feel that adaptive sampling would work well in the project

Sam also recently explained very simply the issue if the sampling is already to low from the beginning :

you need samples to estimate what's the noise/error level that's what that first number is (to estimate the baseline variance).

Imagine you are in a completely dark area where you actually have a hard to reach light. With 8 samples, you'll likely miss it
the renderer might think, there's no variance and pass on.
The min number of samples is here to the rescue: you send a minimum of 64 sample to estimate the actual error/noise level then the renderer can refine with that better variance estimate... using up to the max budget of samples

Source https://discord.com/channels/534861432479809547/534866054019547147/908857113533612073

Cheers