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Thread: Noise/Grain error

  1. #16
    if in Render Properties you don't up the reflection recursion limit to match the reflection samples amount you are effectively wasting you time, I would think somewhere between 32 and 64 samples for both the Recursion Limit and Sample should be enough

  2. #17
    Registered User KSTAR's Avatar
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    Hi Thomas thinks for sending the scene and providing feedback. Your scene rendered fine with no noise. I went back to my scene and upped the render samples as I had in the past but this time added more in the min settings in the min/max camera AA and it improved the noise. The only problem is to get a clean image I'll have to set it to a point were the render times are unmanageable. So I'm going stick to tip David Ridlen shared which is render with a grey environment using manageable AA and render sample settings then in post lower the gamma to bring it back to back. What I've done is render the floor with the grey environment and render the fire in a separate pass against black then comp in Fusion lowering the gamma for the floor image and color correcting it to match the fire pass. It looks fine and the render times times out of LW are manageable
    Kevin Washington

  3. #18
    Registered User KSTAR's Avatar
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    Hi Gerry,

    I took the scene that Thomas Leitner posted and lowered the reflection samples from 200 to 32, which produces noise. As you suggested I then upped the Recursion Limit samples from the default 4 to 32 to match, and there was no change in the noise, the renders are identical the only change was it added 8 secs to the render time.
    Kevin Washington

  4. #19
    Electron wrangler jwiede's Avatar
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    (edited)

    See LW docs here for much more readable, clear explanation (with examples) for those parameters' meaning than my own.

    Recursion limit, and samples params are only very indirectly connected, and there's rarely any reason why recursion limit should go much past 8-16, whereas it's often useful for samples to go higher. Keeping those params "matched up" isn't really useful or desirable. See the definitions at that link for what each param really controls.

    As a quick mnemonic, think of samples as controlling "precision/granularity-of-breadth" tracking a path, while recursion limit effectively controls the "depth" a path can reach overall.
    Last edited by jwiede; 11-27-2020 at 07:35 PM.
    John W.
    LW2015.3UB/2019.1.5 on MacPro(12C/24T/10.13.6),64GB RAM, NV 980ti

  5. #20
    Quote Originally Posted by Thomas Leitner View Post
    I’d first check if the scene renders correctly in LW 2020. I never had any issue coming from black environment.
    Sure, sure, first check if its a setting issue. But as said, I also ran into some weird reflection problems with 2020

  6. #21
    Registered User KSTAR's Avatar
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    I resolved the issue by using DPonts Denoiser as it was the only option that produced rendering times that were acceptable.

    I have another question I'm trying to isolate elements so they can be comped in Fusion. I can isolate the fire by making the ground unseen by camera, but when I try to isolate the ground by making the Fire volume container unseen by camera a portion of the fire remains visible in the ground object and is clipped off where the alpha channel for the ground is. If I render the Legacy Volume and Specular Indirect buffers I can get both of the passes, but I'm curios why using the unseen by camera option for the fire volume doesn't work correctly?
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    Kevin Washington

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