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Add a PrmanDenoiseChannelDefine node to create all the DisplayChannels required for the denoise utilitydenoiser.
Step 2:
Add a PrmanDenoiseRenderOutputDefine node to output a multichannel OpenEXR file for the beauty pass. The file contains all the required denoise channels.
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If your pipeline does not support multichannel EXRs, you can use separate RenderOutputDefine nodes to create an output for each channel defined in PrmanDenoiseChannelDefine. Then use $RMANTREE/bin/exrmerge to combine the AOVs into a multichannel EXR. Use this merged multichannel EXR for the denoise utilitydenoiser. Combined EXR using EXRs created with Katana's RenderOutputDefine 's merge will not work with the denoise utilitydenoiser.
On any RenderOutputDefine nodes you create for denoising, the type should be set to "raw" to avoid any post-processing by Katana. Then make sure asrgba is set off so that the channel names align with what the denoiser expects.
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There are several options available to denoise your Katana renders. RenderMan provides both a command line denoise tool called denoise_batch and a Denoise UI. Note that denoising is not supported interactively, so all denoise renders need to be Disk or batch renders.
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- Render your images out of Katana as a disk or batch render.
- The PRMan 25 shelf has a script called RenderMan Denoiser. Run this script to launch the Denoise UI. You can also access the UI directly from
$RMANTREE/bin/denoise - In n the UI, select "Add Directory..." and choose the directory containing the images you have rendered out of Katana.
- Next select folder icon next to choose the directory your denoised images will be saved in.
- Hit "start" to begin denoising.
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