When I add a displacement node, regardless of whether the input is noise / image, every time I subdivide the surface to get more geometry (whether through direct subdivide or the subdivide surface modifier), unwanted spikes appear.

Here is the sphere without subdividing and an example noise displacement setup.

Noise displacement without subdivide

Here is the same sphere and node setup but with a subdivide surface modifier.

Noise displacement with subdivide

  • $\begingroup$ I tried to replicate this as described with a UV Sphere and I don’t get the same behavious (no spikes). $\endgroup$ Jul 14 '20 at 18:21
  • $\begingroup$ I think this is on your end (but i'm not sure how). I downloaded your file and the rock is smooth at any subdivision level (except 0, of course). I know this isn't helpful exactly, but maybe it helps you narrow things down. Try copy/pasting to a different version of blender or updating your graphics drivers, that's all I can think for now. $\endgroup$ Jul 14 '20 at 18:22
  • $\begingroup$ Oh, I think you're right... it's my GPU (AMD Radeon RX 580). When I switch my Cycles rendering device to CPU, it looks normal. Any idea why that would be? $\endgroup$ Jul 14 '20 at 18:25
  • 1
    $\begingroup$ Not sure, but I've seen the RX 580 come up in a few threads. I'm starting to get the feeling it doesn't play too nice with blender. $\endgroup$ Jul 14 '20 at 18:42

This is apparently an AMD GPU problem. Similar issues have been found apparently. My condolences to anyone else out there on Team Red.



Thanks to Rich and Christopher for the speedy and helpful replies!


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