lateral displacement

[Valentina]

Hi, I'm trying to achieve the following result: an island, with flat surface on the top, and displacement along the walls .. As you can see in the image, flat surface is ok, i drew a displacement map for the island to pop up, and I'm using lateral displacement to get a non-smooth wall... (sorry I'm not english).
But it's like if this displacement only 'faces' one direction.. leaving the other walls of the island quite smooth. Can you help me with that? I'd like to improve myself and understand this...
many thanks

[Dune]

What you can also do is warp the image map (warp shader, with vector displacement as function input, with PF as input). Play with values. That'll make the sides displace a bit sideways. Or raise the terrain first by image map, then add a compute terrain or compute normal with low patch size (depends on how large island is. Then a PF displacing only laterally.
Does the island need to be exactly like this or is any shape okay? Then you can also use a warped simple shape.

[Valentina]

Many thanks, I'll try both ways.. in this case I did need this shape, but warping a ssshader could be great, thank you

[Dune]

Another thing you can do is make a mask of the sides of the island by subtracting the center from the whole, and use that to mask some very big fake stones as child of a surface shader (before or after a compute terrain, see what looks good), so you get some sort of rocky outcrops.
Center would be the image map taking through a color adjust, where you increase the black point, the whole island would the image map taken through a color adjust with white point decreased. Pull the fake stones through a transform shader set to world (final position).