Author Topic: Noise Level Limit vs. Number of Passes  (Read 777 times)

2022-09-25, 07:02:20

BigAl3D

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Let's say I render a scene with a Noise Level of 5 and it goes for 25 passes before denoising and saving out. If I take that same scene an set it to 25 passes and 0 for the noise level, with I get the same render time and quality, or is the Noise Level setting intelligent and uses more rays only were necessary?

2022-09-25, 09:36:10
Reply #1

romullus

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Different render stop conditions does not influence image quality in any way. If your render stopped at 25 passes, it doesn't matter if that happened because it reached a pass limit, noise target, time limit, or you manually stopped the render process - the image will always be exactly the same.
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2022-09-25, 12:23:48
Reply #2

davetwo

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As I understand it, it stops at the quickest reached target if there are multiple targets set. Ie if it reaches less that 5% noise at 22 passes, it would stop then, not at 25.

2022-09-25, 23:48:28
Reply #3

TomG

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Just to confirm what others are saying - the choice of stop condition does not change how things are rendered at all. So in your case, your 25 pass render will be the same as your 5% noise render, as both stop at 25 passes and have done the same thing.

The reason for the option is because you might prefer different stop conditions under different circumstances. Let's say you have an animation, and as it goes through the animation the scene is changing (the camera looking at something else) so if you rendered the same passes of 25 for every frame, some frames will be noisier than others (due to the different objects, materials, lighting, in that particular frame). To avoid that, you can use a noise limit, then each frame will have a similar amount of noise, and if some frames were hard to clean up then they will have rendered for more passes to reach that same amount of noise.

Time and passes are fixed, and will not account for whether a frame is harder to calculate and clean up or not, but of course you can then have an actual estimate of how long it will take to render the animation which you can't have with noise. Thus, if you have to have something to show in 1 hour, you can use passes or noise to make sure the whole animation is finished in an hour, while also knowing that the noise may vary throughout the animation if things change significantly in what the camera is looking at.
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2022-09-26, 12:57:24
Reply #4

Stefan-L

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for animation or if you need the exact same noise quality on different computers, i woudl use the noise limit.

this ensures the image is at the same "quality level" (as time can be different for different frames or on different pcs)

2022-09-26, 16:50:40
Reply #5

BigAl3D

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Thank you all. That explains everything clearly.