Hi all

I am trying to understand what is the proper use of these 3 height-field layers which are always generated by the Erode node:
- Sediment
- Debris
- Bedrock
in the texturing of a height-field.
All the tutorials I found always use custom masks created by the "HeightField MaskByFeature" node with some combination of AO, height and curvature instead of these layers which are already there.
What do they represent and what kind of texture should they be assigned to? What is the difference? Does grass not grow on them and they should be left bare (rock texture), should they be used as a mask for color correcting the rock?
I can not find a tutorial exploring their use for texturing in Houdini or UE4.
I can imagine some of it is left to taste, but I was hoping for some general guidelines, if someone can kindly point me to some.

Thanks