So far, a simple shape shader or painted shader does give nice control over where the cliffs/outcrops occurs. The painted shader is
very useful, and simple, but a bit trickier to control exact dimensions since it's essentially sprayed on. A simple shape shader definitely has it's up side since the rocky spires and faces tend to be fairly vertical at along the outer edges. But the shape shader rectangle can't be flipped up vertically to fit the exact mountainside(or can it?), so it's more problematic to get it to fit the exact area of the cliff face. I'm still testing though, and both shaders will control where the rocky look appears, which is very handy.
Now, anyone know of a terrain clip or other rocky formation that might happen to plug in as rocky spires or as broken rocky faces? I'm testing the strata shader, but it wants to put horizontal plateaus in places, and other desert cliff or desert mesa sample .tgd's seem much more complicated that what I could probably get away with. But so far I'm having some fun experimenting trying to match the sample in the OP...so back to work
Thanks for the help.