Black artifacts on plane with procedural displacement I'm trying out the procedural displacement in 2.8 with Cycles following this tutorial. The object has 100 subdivisions in addition to a SubSurf modifier, and one material with two shaders separated to form rocks and some water. When rendering with 4 levels of subdivisions, there are these black marks all over the water.



When I render with only 3 subdivisions, there are fewer artifacts.



Shouldn't more subdivisons give a more realistic render?
.blend
Sorry for the late answer, but those are not artifacts. The person in the tutorial used procedural displacement to create "waves" in the water by adding a noise texture to displace the water surface, then stretching it in one direction. If you look closely, the black marks are actually parts of the waves.

Take a look at the noise texture you used to create this effect and make sure it is scaled properly. This also makes sense because displacing a more high-res geometry just results in more intricate details like you have noticed.

A little advice for later on: when following a tutorial, don't just try to copy everything. That will get you a result, but in the end, you have learned nothing. Try to understand what the person is doing. This will teach you a lot, and will also make it easier to find and solve mistakes.