AI Denoiser is awesome - thank you, OTOY

[J.C]

Here's the result.
Interesting that it takes considerably more time to do the initial render with Denoiser enabled.

The difference in my tests with your scene is 1.5 seconds more with denoiser.

[richardwright]

If I switch to the Denoiser pass its completely white

[richardwright]

Yeah everything works in your scene.
I'll have a play and see whats different.
I notice you don't have Denoiser enabled in the Camera Imager Render

[J.C]

Yeah everything works in your scene.
I'll have a play and see whats different.
I notice you don't have Denoiser enabled in the Camera Imager Render

Denoiser is enabled in 3d view window (Preview mode). Override toggle overrides all Camera Imager setting so it works for all cameras in the scene.

[richardwright]

Yeah noticed that.

Well your scene works and mine doesn't and I can't see what the difference is.

You have Render Layer and I have View Layer but that's all I've noticed so far.

[richardwright]

I load your scene and press F12 - everything works.
I then open another copy of Blender, load my scene, press F12 - and it's not working.
If I then go back to your scene and press F12 - it no longer works (and takes a lot longer as well).

[richardwright]

I think the only solution is to save an empty copy of your scene and save it as the default.
And thanks for all your help JC

[J.C]

I load your scene and press F12 - everything works.
I then open another copy of Blender, load my scene, press F12 - and it's not working.
If I then go back to your scene and press F12 - it no longer works (and takes a lot longer as well).

Strange issue. It has never happened to me.

[richardwright]

I have been playing around with some of the kernel settings.

If I set Parallel samples to 16 and Max. tile samples to 32 the denoiser no longer works in your scene.

Strangely, if I lower it back to 4 and 8 it still doesn't work.
I have to close and then re-open blender.

I think it's the graphics card running out of memory and might explain why it happens on my machine but not yours.

[J.C]

I have been playing around with some of the kernel settings.

If I set Parallel samples to 16 and Max. tile samples to 32 the denoiser no longer works in your scene.

Strangely, if I lower it back to 4 and 8 it still doesn't work.
I have to close and then re-open blender.

I think it's the graphics card running out of memory and might explain why it happens on my machine but not yours.

Be aware that Parallel samples can take quite amount of GPU memory. Default high setting at 32 is in my opinion too high compared to the speed increase it offers. 4 or 8 is optimal in most cases. If you have 11GB memory it might be useful to have it higher but not 32 as it does not offer any speed increase compared to setting at 16 or 8.

If you can connect your display to other GPU that is not used for rendering. This may get gack some memory that is used for display and other apps.