The latest 2.3.1.1 has a UI to run the Arnold denoiser (noice) from Cinema 4D.
Basically you have to render the scene with an EXR driver using the options Merge AOVs and Output Arnold denoiser AOVs. Than you have to run the noice command line tool on the output images.
If you want to use the OptiX denoiser, you have to enable the Denoise (OptiX) flag on the AOV.
I know this is an older post and response. I need to generate ALOT of renderings shoing various option on a product. Is there any way to automate the Arnold Denoiser on the final renderings? I understand the need for the exr. I was hoping to find a solution similar to Vray where I can have the denoiser at the end of the rendeirng. I know the Ptix will do this from what I understand but it is not a recommended denoiser for final renderings. I need a pretty high quality result so I am thinking I need the Arnold denoiser.
Currently automation directly from the plugin is not possible, the denoiser is designed as an additional step. You can call the denoiser from a c4d python script, like this. You can also write a script to denoise multiple files in batch.
We are planning to improve the workflow in a future release, but no ETA yet.