I have a new problem that I don’t recall experiencing with Blender 2.82: I often get a blank image when trying to use viewport rendering (cycles) and the upper left status message simply says “Cancel”. Usually, I can just switch to the line work and back again and then it renders fine. But today, I had a file that would cancel and nothing can make it decide to render. I tried even restarting my computer and it still won’t do a rendered preview. Screen shot:
I have dealt with much larger files with no trouble, and this one worked the last time I opened it. I tried both gpu and cpu for rendering, no luck. I’m not using experimental features. My system has a Threadripper 2920x CPU and two 2070 supers, 32 GB ram. Memory usage on the GPUs is low (this shows just one, but memory usage was the same on the other):
The scene renders just fine on the final render, its only the viewport render that cancels. It cancels a few seconds after clicking the rendered viewport button.
I am using Optix, but no AO nodes. I have the same composting set up that I use on my other files with an AO pass mixed in with a mix node. The other files work fine.
I did make this discovery: CPU viewport rendering without Optix viewport denoising works. With it on, it cancels just like GPU. GPU cancels either way. Final rendering with Optix denoising on works fine with GPU.
Optix denoiser is always GPU, no matter if you have CPU selected.
You should open a bug report about this in developer.blender.org. But you should share a scene with developers where the problem can be reproduced, or at least some log reports of the problem that they will probably tell you how to get it.
