Arnold Denoising stopped working for this scene, but why?

[michael_grosberg]

I'm using a simple scene to render multiple beauty shots of objects. basically a ground plane, a light and an arnold sky background. all very simple. I'm using fairly low render settings and so, I turned on the Optix denoiser. The result was a dark-gray output, as if there was no light whatsoever in the scene.

I'm attaching the scene with a teapot, and both the denoised and non-denoised output.

I'm using 3ds max 2021.

Can anyone help me understand what I did wrong and how to fix it? 

[madsd · Accepted solution]

You are not too far off.

- I disabled Legacy switch, its not working on GPU, so just disable.

- Disable Exposure override, its a post process which is not nested in the denoised output.

- Reset the skys exposure to 1:0 from 1:8

- Add a RGBA Beauty AOV and tick the Denoise flag.

- unticked the OptiX denoiser on the main pass, you render 2 images instead, the normal and the denoised on same time.

Now the RGBA and the denoised image is identical in terms of light, and the denoised image renders in a fraction of the time.

So you mixed a bit of stuff that is redundants and not needed, but just do like this and you will fly fine.

Hint, dont use production render........its sloooooooow to work like that, use Active shade, fresh, upbeat, instant reaction, you hit render 1 time in a session and let it keep ripping the framebuffer instead of testing, pushing render, etc, you will be much slower than active shade workflow, possibly by orders of magnitudes slower.