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I'm setting up a displacement map, but some parts of the mesh are all black and glitchy. (See Attached Photos) I think I've set up the Displacement correctly:

  • Render Engine: Cycles Render
  • Feature Set: Experimental Mode
  • Modifiers: Subsurf With Adaptive Subdivision
  • Material Surface: Displacement and Bump

The Texture I'm using is from Ambient CG: https://ambientcg.com/view?id=Rocks011

(I Downloaded The 4K JPG.)

If anyone can help I'd appreciate it! Thanks! enter image description here

enter image description here

enter image description here

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  • $\begingroup$ Possible that lowering the normal map strength or just setting it to object space will solve this $\endgroup$ Aug 13 at 18:34
  • $\begingroup$ Hello. Thanks for the idea, but I tried that and it didn't help. $\endgroup$ Aug 13 at 18:39
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    $\begingroup$ @Kifayat Ullah is on it.. so I won't add to that, except to say that if you want to see the subdivision the renderer is actually doing, you can plug a Wireframe node into the Surface output. If you want undercuts on your rocks, you would need a displacement map rather than a height map, and to use Vector Displacement $\endgroup$ Aug 13 at 19:15
  • $\begingroup$ Thanks! @RobinBetts $\endgroup$ Aug 13 at 19:23
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This happens when our gradients are no longer gradients. This is what I mean. Look at this setup

enter image description here

As you can see, these nodes are creating a square. Now, what the color dodge node is doing is that it is controlling the fall-off of the gradient or you can say the bevel of your displacement. Look what happens to the displacement when I change its value: enter image description here

Now, if I put the value to 1, the square becomes a solid color. That is when displacement gets messed up. enter image description here

What you should do with the displacement of this texture is that use the displace modifier for accurate geometry. Not all textures should be used with the displacement node only. There is another way.

In this instance, take a plane. Then make sure you have adaptive subdivision on. Then, go to the modifiers and add a "displace" modifier. What that will do is that it will allow you to displace your texture as real geometry. This is what I mean. Once you add the modifier, this is how it is going to look like. Your plane is going to change its location: (btw, im using the 1k version of the rocks due to my potato computer, hehe) enter image description here

Now, in the displace modifier, click on the "new" button. Then, click on this button: enter image description here

It should then open the texture tab. Now click here: enter image description here

Then browse the displacement texture of the rock texture you downloaded. You should now see this: enter image description here

Now, go back to the modifier tab and lower the strength of the displace modifier. You should now get something that looks more better.

However, you still see the lines, even if a little (use auto smooth to get even less lines). And I think that is because there is the "gradient" problem (I mentioned above) in the rock displacement texture.By bluring the texture, you can get rid of that. Open any photo editing software and blue the texture. And then repeat the above-mentioned steps with this new blurred texture. This is what you should have once you use the blurred image (keep in mind that you need to blur it "very" slightly):

As you can see the lines are totally gone Here is the final result: enter image description here

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Final result (I'm just using the 1k version that's why there isn't much detail so please ignore that) enter image description here

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    $\begingroup$ Is your question solved? Do you want me to explain something? $\endgroup$ Aug 13 at 19:00
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    $\begingroup$ Oh! I meant that it's sometimes better to use the displace modifier rather than using the displacement node. That is when you want (in this instance) to put something over the rocks texture, Now, if you are using the displacement node, you would have to go into the rendered view again and again to make sure that the object you are putting on the plane is not clipping with the rocks. So being able to view actual geometry of the rocks is going to be helpful. Otherwise, feel free to use all textures with the displacement node. $\endgroup$ Aug 13 at 20:13
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    $\begingroup$ There is no problem at all. Pardon me for what I said because it feels confusing to me as well. $\endgroup$ Aug 13 at 20:14
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    $\begingroup$ The problem with the texture was that it had that "gradient problem". This problem occurs when there is/are edge(s) that are very sharp and are not defined by any gradient. See the square shape eg. I gave above. The displacement glitch is seen when the square turns into a solid white color with no gradient information. Thus, it leaves the software confused about how it should displace the hard edge / the shape with no displacement information, basically. So to solve this, we blurred the image which basically softens the hard edge thereby creating a sort of gradient. $\endgroup$ Aug 13 at 20:17
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    $\begingroup$ Ahh ok. I see. Thanks for the clarification! I blurred the Displacement map and it fixed the problem for the most part. Thanks so much for your help! $\endgroup$ Aug 14 at 1:44

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