Hi friends im haveing a problem with microdisplacement.
can you share your blend file ?
How are you displacing?
Did you simply plug some grayscale map into the Displacement output and are you using 2.80 or 2.79 Master?
Displacement goes in more than one direction. It can go along the z axis but also along the x and y axis.
If you plug a grayscale map into the displacement output the values of displacement are the same along the z, x and y axis.
Since you only want to displace outwards, that is along the z axis you should probably use a displacement node and plug it into the Displacement output. Then plug your grayscale map into the height input of the displacement node.
BTW, if you want to see how this works you can plug a Combine XYZ node into the Displacement output and your grascale map into either one of the x, y or z inputs of the Combine XYZ node
Please, for next time you share a simple .blend file, the version of Blender used, and all relevant information. I am not sure if you are using stable or experimental feature.
For 2.79/2.8 from master/buildbot you must use this Displacement node connected to Displacement in Material Output:
So if you are using traditional method where you probably have a Math/Multiply node connected to Displacement input in Material Output node, remove Math node and connect directly to new Displacement node in Height input and configure it in this way:
You start with very small scale value because depending on the mesh it can become very heavy and even block your computer.
Finally Thank you Yafu
“just a plane and substance height map.”
I needed blend file to investigate node setup, and edit it live, then share it back, but you already posted screenshot, and other members gave you links and information how to do it right yourself