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Any idea why the purple plane is showing through? These planes are parallel. Using Eevee. If I create this topology fresh I don't see the issue. But in this particular blender file, I somehow arrived at this problem and I don't remember what all I was trying. Which setting may be causing it?

parallel planes

good file

bad file

AKV
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  • purple plane's z = 0.0 m, red plane's z = 0.006 m. However, strange part if that I created exact same topology in a new file and there I don't see this issue at all. Is there any setting I might have done accidentally to cause this? The blend mode is set to "opaque". I also observe that blend mode "alpha blend", fixes it. But "opaque" should also work. – AKV Nov 16 '20 at 06:28
  • good file and bad file have the same topology. good file doesn't have that problem, but bad file has. And it only happens when view is rotated. – AKV Nov 16 '20 at 06:48
  • Some Eevee issues of that kind can be solved reducing the camera view clip start and end to the minimum required in the scene. – josh sanfelici Nov 16 '20 at 07:34

1 Answers1

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This is called z-fighting, and it's caused by blender not being able to properly decide which one to draw in front of the other. You need some difference in the z coordinate, and if it's not large enough this can still happen at great distances due to floating point precision funkiness.

Allen Simpson
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