When rendering process reaches its final, shadows becomes rough (sharp)

[summerson1990]

Hi! I’m trying to figure out the problem when rendering process finished all the shadows on ground plane (infinite plane with wrapper material with casting shadows and reflections) becomes absolutely rough but even on last second before the rendering finishes the shadows looks fine as I need it (light, soft, blurred). Why is this happening?

[konstantin_chaos]

This sounds very strange indeed.
Can you please share an example model that presents the issue.
If that's not possible screenshots of the 2 states might also help.

Thank you in advance,
Konstantin

[summerson1990]

This sounds very strange indeed.
Can you please share an example model that presents the issue.
If that's not possible screenshots of the 2 states might also help.

Thank you in advance,
Konstantin

Sure, look my test .skp scene and here are two saved images (1 is when rendering in process 2nd is when rendering has been done)
Look at my gif you'll probably notice how much differs that 2 images.

[konstantin_chaos]

Thanks for the scene.

I can see the effect here - It seems that it has to do with the Denoiser somehow.
After the rendering is done the Alpha gets denoised, producing the result you see.
I will continue investigating because I believe - if the RGB image is saved the alpha should not be denoised ...

On the other hand I'd recommend you don't use the Nvidia denoiser for production rendering.
It works well during interactive but when it comes to final production rendering the V-Ray denoiser does a much better job.

Regards,
Konstantin