Thanks.
In your situation the smoothing has quite an effect because you have very steep features on your terrain.
I'll explain briefly why in many cases it is beneficial to use smoothing in the surface layer which acts as a base for fake stones:
Smoothing effect makes the surface layer follow the smoothed normals provided by the last compute terrain node which precedes your surface layer.
If you incorporate a fake stone the "normal" way, like the 5 or 6 you had in one column, they would automatically incorporate the displacements which happen before those shaders.
Having fake stones shaders as child layers of a smoothed surface layers allows the fake stones shaders to "start with a clean sheet". In other words, you can texture and displace them separately from the terrain.
The steep features change faster than the patch size (determined by compute terrain) of your terrain and thus the smoothing smooths out large chunks.
Luckily, in your case it doesn't matter too much since your stones are pretty simple.
In any case I'd always use the merge method I described you, with or without smoothing then.
If you don't merge this way then stones will exist on other stones.
Unless you like that effect of course
Cheers,
Martin
