GPU final render is very dark (depending on number samples)

Question

Not sure what happend - GPU rendering worked fine before - but now I cannot get blender to GPU render, though rendered preview works(!), so it shouldn't be driver. I have an AMD card, cannot remember driver updates recently. Updated to latest after the issue happend and it didn't help.

Problem is not related to file - same thing in the new projects now.

Also it depends on the number of samples, below are the render results for 1, 2 and 3 samples respectively. On 50 samples it's like almost completely black.

Did anybody had similar issue? Is there a known solution?

How does it work on CPU ? Did you try checking if there is a setting that differs between preview and final render and isn't supported on AMD GPU ? — Mr Zak, Oct 31 '16 at 19:00
It works on CPU (slow as hell, but seems like I don't have a choise now). It worked previously (like a week ago), so everything should be supported. I didn't change my PC configuration or anything - it just happend some day... — Anton K., Oct 31 '16 at 19:20

score 1 · Answer 1 · answered Oct 31 '16 at 19:34

Ok, so I found (thanks to Mr Zak!) that one of the differences between preview and final render was a Motion Blur. Even though it is disabled in preview and I had it disabled in render settings, when I enabled it in render panel and everything works again!

Though I definately remember it working from default blender file (where I suppose it was disabled?)... and this is seems like a bug, but hey, we found a workaround!

GPU final render is very dark (depending on number samples)

1 Answers1