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Circular Banding in Renders
Posted: Wed Mar 29, 2017 11:50 pm
by indigoGnat
I've had this problem with a few camera angles and it seems mainly to happen when I turn up the level of detail on a displacement map.
I've tried slightly adjusting Ray epsilon, and it changes the banding slightly but it doesn't get rid of it.
The banding seems centered around the camera and it looks almost like an LOD issue.
I'm not sure how to fix it.

Re: Circular Banding in Renders
Posted: Thu Mar 30, 2017 6:41 am
by bepeg4d
Hi indigoGnat,
I guess you need to reduce more drastically the Ray epsilon value.
At what scale are you working?
ciao beppe
Re: Circular Banding in Renders
Posted: Thu Mar 30, 2017 2:04 pm
by indigoGnat
bepeg4d wrote:
I guess you need to reduce more drastically the Ray epsilon value.
I've tried that, I've gone from 0.000001to 0.1, taking them up in step by step increments. The banding never goes away. It just shifts position, like ripples coming from the center of the camera. I tried again this morning, hoping maybe restarting my machine might have changed things but it's the same.
Re: Circular Banding in Renders
Posted: Mon May 01, 2017 5:52 pm
by alexchopjian
indigoGnat wrote:bepeg4d wrote:
I guess you need to reduce more drastically the Ray epsilon value.
I've tried that, I've gone from 0.000001to 0.1, taking them up in step by step increments. The banding never goes away. It just shifts position, like ripples coming from the center of the camera. I tried again this morning, hoping maybe restarting my machine might have changed things but it's the same.
I ran into this exact issue where I was getting banding with displacement only. I was on version 3.04.5. I found that increasing the displacement resolution (in my case to 8k) helped remove the banding. My theory on why this happens is that if you look very closely at the displaced object, the geometry isn't perfect with some tearing happening (even in 4k, it really depends on the displacement), and Octane is trying to generate shadows for all the tears in the geometry. This is why the ray epsilon
does have an effect on the banding, but never solves the issue.
By making the displacement a higher resolution, it reduced the tearing of the geometry and resulted in almost no banding at all.
Re: Circular Banding in Renders
Posted: Tue May 02, 2017 9:40 am
by bepeg4d
Hi alexchopjian,
resolution and depth have a great impact in displacement quality, but if you update to v3.06, displacement has a new filter parameter that helps a lot with low res / low depth images.
If you scroll the following link, you can find some example images:
viewtopic.php?f=24&t=60014
ciao beppe