Post Denoiser, what's the secret?
Disciple
Posts: 249
Rendering a 1.4MP image with Iray. Illumination comes from a large set piece with scattered emitters, noisy and difficult to converge, so I activate two Post Denoiser switches. (Why two switches to do the work of one?)
When the render begins, samples start to appear.
Denoising briefly kicks in,
...and then it drops out.
A few more screen updates and it kicks in again,
...and drops out again. This recurs several times.
When the timer expires (way past the 7200 seconds specified), is the final canvas denoised? It is not.
How do I gain control of this mercurial feature? How do I coax it into acting upon the image I want? The only parameter I see is Post Denoiser Start Iteration, with a default value of 8. I've seen it make brief appearances near the finish of a render, and it looks promising, but never at the final product. Thanks in advance for reading and for advice.
[Edited for images.]
Hallelujah!
Disciple
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Comments
well Stonemason flipped a switch in my brain when I realised he starts the iteration from 0 on his sets for faster cleaner settings
I do that now
...the iteration on his sets? Are we looking at the same feature? I'm describing the Post Denoiser under the Filtering subheading of the Render Settings tab.
[edit=1] I'm changing the only parameter to 0 just in case, and rendering again. The behavior seems nearly the same. Over two hours will tell. [/edit]
Hallelujah!
Disciple
iteration when the post denoiser kicks in
by default it's 8
you may have a very emitter heavy scene though so this is probably not helpful
It seems I have a deeper issue than taming the denoiser.
(Gnashing teeth) I believe my Task Manager has been trying to tell me that the RTX 3070 in my tower has ceased participating in Iray rendering some time in the past. I know not when. At one time I rendered with GPU only to keep my CPU temperature down. Now when I deselect CPU under the Hardware tab and disable fallback, I get no pixels from Iray, just an immediate black canvas and process end. (Gnash again) Task Manager shows GPU bursts of 3D activity when I manipulate the interactive window, and when the denoiser makes its occasional appearances. It's not completely inert.
Now, the RTX4060 in my laptop running 4.23 does carry its share of the Iray workload, and configuring the hardware in the same way does activate the denoiser in the manner you both describe, so thank you. It works. My issue now is trying to discover what went wrong with my tower's configuration, and how to get the GPU back in the ray-tracing pipeline. Pray for me.
Hallelujah!
Disciple
How's your VRAM holding up? That's the main reason for failed renders.
As garret_3D said, not having enough VRAM on your graphics card, for the scene you are rendering, is the major cause of problems you describe. Try creating a new scene with only a primitive cube with not too many divisions (10 divisions would be a good test). Will that minimal scene render with your RTX 3070?
Task Manager is not entirely reliable, at least by deault, in showing GPU usage - I would use a separate tool, such as GPU Z, to see what was happening 9and also check the log file)