Hi Unity,
I’ve been really enjoying the awesome new powerful tools in Unity5. Especially the real time GI but this morning I noticed issues in low light conditions, I get severe banding and artifacts.
Video
http://www.veiviev.com/uploads/unity/banding.mp4
Images
Does anyone know how to overcome this? It almost looks like the similar issue people get with compression when baking.
V
Bumping this thread. No replies?
Can anyone from Unity confirm this is a bug? The banding often appears in low light conditions.
Another video example:
Bug and project submitted
(Case 718390) GI banding in low light conditions)
I’ll give this a bump too; having the same problem.
Thanks for the backup.
No replies here so far from Unity and nothing about the bug submitted. I hope this gets addressed?
A partial solution to this is make sure your camera is HDR-enabled. This smooths out a lot of the banding because of the larger range of light values permitted. I’m not sure, however, that the banding apparent in a non-HDR scene is avoidable. We need Unity tech person or somebody with more knowledge than I who could shed some light on this to help explain this issue.
Thanks. Yes it is active. You can also see that it happens in the Scene view-port, not just the camera.
I can also confirm the bug. I also reported it last December (case 657956 ). I had gotten a confirmation for the QA back then.
From what I can tell, since the early 5.0 beta, they have fixed a lot of bugs with the integration of enlighten with Unity, but the tech itself remains exactly the same. That’s why I think most of these bugs will be solved when Unity upgrades to a newer version of Enlighten (3.02) which is supposed to happen eventually.
Can anyone at Unity confirm when this bug will be fixed? It still exists with Unity 5.4.
Do another bug report. My report is so old I hardly think it’s relevant now.
I think I have come across this before, the darker the scene is the worse it gets.
Do things improve if you increase the realtime resolution?
Thanks for the reply. Yes it will happen in dark scenes. Increasing the resolution does not help.
If you aren’t using linear + hdr, then banding is unavoidable in low light situations because there aren’t enough colours for the resolution to display. Does using the cinematic tone mapping and color grading on bitbucket with “Dithering” option enabled fix this for you?
If you are talking about spaghetti lines then these are not banding, and banding is the wrong term for it. Those are artefacts and any bug reports may help more there.
The scene uses linear (always do) and HDR. Cinematic and tone mapping does nothing, as you can see it happens in camera and directly in editor.
I think the video example clearly demonstrates the banding, or spaghetti lines, however it should be phrased. It can really break any attempt at realistic lighting.
I’m getting the exact same banding pattern shown in your second video. The only thing that seems to help is setting the general GI default parameters to high, I’m guessing you’ve probably tried that though. Would be nice if a Unity person could say what’s going on.
Thanks yes the same, I’ve tried all settings, problem solved as much as possible. The banding is only evident in low light scenes.
Banding in really dark scenes is unfortunately unavoidable and is usually worked around in post, but this artifact going from dark to bright to dark is unexpected. We seen this snaking/spaghetti artifact before and we’re looking into it. Thanks for putting together the reproducers.
Understood. Many thanks for looking into this Jesper.
Is it because of RGBM encoding (I mean the banding)? Have you seen the encoding “fix” that Ignacio Castagno did for the witness? I believe he was using max(r,g,b,1). Aras and Robert rejected the approach based on this : Unity Web Player | "Sample"
But that was specific to DXT5 and I believe max(r,g,b,1) has better results if it’s uncompressed. (or maybe I remember it wrong, it’s been years, and maybe with enlighten it’s not relevant at all any more, sooo… whatever 
)