(Edit) the bottom screenshot is actually good i would also like to re create this type of mountain because with some editing it can look just like the top screenshot
For the broad shapes, using Voronoi devices can be super helpful, and following it up with Curves, Bias/Gain, or Levels devices can assist in making the shapes more dramatic.
this does not really do much atm, but i will keep tweaking, i think i need more packed walls because every time a wall looks like this from above it is usually perfect
where as thinner walls like this are not good
One thing to keep in mind is that erosion is going to remove material, so it will have a much more drastic visual effect on areas where there is less material to remove. Thin “spines” will often not look good after erosion because of this. There are several ways to work around this, I will list my two favorites:
Adding extra material: Use an Expander device with the Gaussian mode to soften the spines a bit, giving them more material to lose.
Hardness Maps: Use a Select Height (or, in some cases, a Select Slope device to create a map/mask where the spines and peaks of the mountains are pure white and it fades to black (or near black) from there. Plug this into the Hardness Mask input of an Erosion device, then max out the Rock Hardness parameter. Your spines/peaks will maintain full hardness and be less affected by erosion while your lower altitude “softer” terrain will get eroded as usual.
Using either method (or a combination thereof) should allow you to keep those nice sharp spines when applying erosion.
