Weird Black Lines On Displacement

The model is simply a cube with a subsurf modifier turned all the way up and a material with displacement.
I don’t get why I’m getting these black lines.
Any Idea?

Your height map for displacement must be 16 or 32 bit. Having 8-bit texture causes this kind of banding artifact.

Odd, that used to not be the issue with previous versions of blender.

So, can I just convert it to a 16 bit?

You can but it won’t be %100 identical, because you’ll add info/pixel that does not exist in 8-bit texture.

It would be useful if you’d post .blend file so others can look into problem.

I think I may have sort of figured it out, seems it only happens when I boost the subsurf modifier over 6 subdivisions.
Not sure why, but it seems that’s the culprit.

That’s odd. Consider reporting this as a bug, so developers could look into it. (Help > Report a Bug inside Blender)

Don’t report it, it’s not a bug.
The ridges are banding artifacts from using a low bit depth image. It isn’t visible at low subd levels because they’re not extracting as much information.


Are you using Blender 2.8? Can you reproduce the problem in Blender 2.79 downloaded from Buildbot’s nightly builds? Could you share the .blend file with packed texture?

Well, here’s your answer:
Camera clipping. Your subdivision was small enough to cause pixel fighting :slight_smile:
I wanted to reply you yesterday but blenderartists told me to wait 15 hours before I can write again ^^ tragic

I honestly do not think it is a bit depth issue.
Despite the fact this hasn’t happened before, I’ve used it as a bump map (not a normal map) and it’s very smooth.

I just started a second round at rendering, this time with a height map at half the resolution, same space in banding, so I’m certain it is not a bit depth issue.

Without more information, I can only say that it looks like a banding issue. Can you provide a .blend file, or the height map?

As I wrote, it’s pixel fighting issue. You can either play with it by camera clipping (not always helping (increasing should help)) or use adaptive subdivision. There is no point of subdividing it more than screen can show pixels. Antialiasing is done with samples anyway.

I will post the blend file soon and adaptive subdivision does not change the issue.

Do you get artifacts when you route it out to color only, no displacement at all? If so, what are the nodes? Some generators can misbehave if they exist exactly at a point in space where things happen in them, i.e. checkers should have a tiny offset in coordinates to not cause issues. When it happens to me is not consistent, but I know how to fix it so its not a big deal.

But yeah, if you have clipping values like shown above that can’t end well either.

Ok, so here are 2k and 4k heightmaps rendered showing the exact same slicing going on, I went ahead and used adaptive sub to save time (I’m using my crappy laptop).
I’ve also attached a pack blend file. I got the textures from and the HDRI from both are free.




.blend is not linked, only plain text

camera bug.blend (328.4 KB)

Try this.