Spend rendertime on empty background

[joie]

Hi there,

I don't know if this is normal or not, aso I'm asking.

I have a layer with a tiny object in it and it renders super fast that part in just 4 seconds. But then it keep spending time rendering the rest of the image, which is completely empty and black, of course.

Shoudn't it spend no time at all rendering that empty part?

I'm rendering in auto cropped EXR, so I'm pretty sure there is nothing in there.

Thanks.

[thiago.ize]

I would suggest using adaptive sampling so that the empty parts render quickly.

[Stephen.Blair]

autocrop happens when the image is written to disk, not when you watch the render in the Arnold Render View

autocrop is a property of the EXR driver, and the driver writes the image to disk, not to the screen.

[joie]

I know auto crop happens at file writting, I was saying that just to confirm there is nothing in the background to render.

I would love to use the adaptive sampling, but I never had success on rendering at same quality as regular sampling with LESS rendertime or even SAME rendertime. It is always slower.

[thiago.ize]

Adaptive sampling had a bug that could cause increased noise. It was fixed in Arnold 6.1.0 (https://docs.arnoldrenderer.com/display/A5ARP/6.1.0.0), so if you haven't tried it recently, I'd give it another shot.

If it still gives you trouble, for this particular case it should be easy to force it to be faster than no adaptive. Set AA=2, AA_max to whatever you actually wanted, and the threshold to 0.000001 (something small). The completely empty regions will end up using AA=2 and the rest, because of the very low threshold, will always use AA_max, so you'll get the same quality there.