This is the cliff-face-generating part of the world maker that I posted recently. Still more details and controls that I would like to add, but its working pretty well in Houdini and directly in Unreal Engine!
A flipbook of the build-up running in Houdini, then a few shots in UE4.
A few extrusion and mesh detail steps with random modifiers per strip.
Lighting only mode within Unreal Engine.
Quick drop into a landscape generated in UE4 with the foliage instances turned off.