I was rendering out a simple animation of a sphere with some textures on it and I noticed that in the rendered frames there appears to be some horizontal lines that appear on the middle left side of the sphere which you can hopefully see in the image that aren't intentional.

Sphere texture that has horizonal line artefacts

I then had a closer look at it in the viewport and they are also faintly visible. enter image description here

Here is a screenshot of the sphere material, as well as a screenshot of the scene setup. enter image description here enter image description here

For rendering I used 128 samples and used OptiX denoising, the viewport image used 64 samples and used the OpenImageDenoiser.

Any ideas what could be causing the issue?

Edit: Here is a close up of the lines. They may not be as visible in a still image but are more apparent in an animation. Hopefully you can see them better. enter image description here

  • $\begingroup$ I don't see the horizontal lines you're refering to. Maybe upscale the image and mark where the horizontal line is with a circle or something like that? $\endgroup$ Aug 26, 2021 at 18:26
  • $\begingroup$ @AlexandreMarcati Hi, I've edited the post to add a close-up of the area with the lines. Hopefully you can spot what I am talking about :) It is definitely more obvious in a rendered animation. $\endgroup$
    – Danny
    Aug 26, 2021 at 18:31
  • $\begingroup$ I see now. Have you tried increasing subdivision levels? Or maybe it's from the reflection of the floor plane reflecting off of slightly different normals on each 'streak'. $\endgroup$ Aug 26, 2021 at 18:36
  • 2
    $\begingroup$ @AlexandreMarcati You're right! I was using an Ico Sphere with 5 subdivisions which apparently wasn't enough. I've added a subdivision surface modifier and the line streaks are gone. Thank you for the suggestion! $\endgroup$
    – Danny
    Aug 26, 2021 at 19:43

1 Answer 1


It's looks like a shadow terminator problem

Tweak the Shadow Terminator Offset value in the Properties panel > Object > Shading until effect will disappear:

enter image description here

Bigger light size and more subdivision levels also solve the problem.

  • $\begingroup$ Playing with the value did not fix the issue and the higher the value the stranger the sphere. I did find a solution in the comments which was to add a subdivision surface modifier to the object. Thank you anyways because I never knew this property existed and now I have something to read about:) $\endgroup$
    – Danny
    Aug 26, 2021 at 19:47

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