David Desousa avatar image
David Desousa asked

Max to Arnold Denoiser difficulties

I have been trying to learn how to use the Arnold denoiser for animation in max 2020 and max 2021 but have not been able to follow the documentation provided here:

which states:

The workflow is as follows:

  1. Go to the Denoiser tab and enable Output Denoising AOVs under Arnold Denoiser. This will automatically generate the normal, depth and albedo AOVs required for the Arnold Denoiser.
    You won't see these AOVs listed on the AOV tab, but they will be added to the rendered output.
  2. Ensure that you are rendering out to EXR.
  3. Render the scene. Alongside your beauty file (id enabled), Arnold will save an EXR version of it, also containing the AOVs needed for denoising. They are named after the beauty filename, postfixed by "_Noice_Input".
  4. Go to the Denoiser tab.
  5. Choose a rendered _Noice_Input EXR image in the Input and a directory for the output (denoised) files.
  6. Choose whether you want to denoise a single frame or a sequence and then select 'Denoise'. This will start the denoising process based on the settings that you have chosen. The denoised images are saved in the output directory, now postfixed by "_denoised".

Step 1 is easy enough being just a checkbox with no other user input required

Step 2 says to ensure that you are rendering out to EXR. So I check the file save box and when prompted, give the name of the output file selecting open .exr as the file type

Step 3. I render the scene (production render) and there is a file in the output folder I specified with the name, MyFileName.exr. But there is no separate file named postfixed by "_Noice_Input" which is what step 3 says I should feed into the input on step 5. And when I enter the single .exr file that was saved by the render operation and specify and output destination for that, no additional file is outputted and I get the following info from the log,

noice [47ab20b9] - the Arnold denoiser

Using 12 threads.

Loading images...

Loading file "E:/3dsmax/renderoutput/Camera_Dan POV Cheat.exr".

Required metadata not found, check that the image was rendered directly with Arnold.


Denoising complete.

Step 3 also states, “Alongside your beauty file (id enabled), …..” which suggest to me that I should add the beauty pass (RGBA) with ID enabled? Not sure how to do this. I did add the following AOVs using the AOV manager (RGBA, diffuse direct, diffuse indirect, specular direct, specular indirect), but as I mentioned above I got no denoised output.

Can anyone provide any insight into what I am doing wrong and how to use the denoiser with Arnold in Max 2020 or 2021?

Seaprately, for a single frame. I did try the Denoiser Noice under the Imagers tab of the Render setup, which doubled the render time, but definitely reduced noise for a single frame. But since I will ultimately need multiframe animations, I need to get the .exr workflow via the Denoiser Tab going.

Thanks in advance for any guidance.

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Stephen Blair avatar image
Stephen Blair answered

I just tried it again to be sure, and there was nothing special to do.
Enable Output Denoising AOVs and render an EXR. I got the _Noice_Input.exr

I would start by checking the Arnold log (Verbosity Level = Info)
The highlighted part of my log shows that the denoising AOVs are part of the output.


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David Desousa avatar image
David Desousa answered

Thanks Stephen for your response. In fact, when I first removed the AOV's I had created for the Production render and then followed the simple steps outlined in the guide, I did get the _Noice_Input.exr output and the denoising step went perfectly. So my mistake was thinking I had to add AOV's in addition to those automatically created by Arnold. And apparently manually adding AOV's pre-empts the creation of _Noice_Input.exr output. Sorry, my mistake. Also, the denoised output looks very good. Thanks again for your help.

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