Blending meshes with landscapes with no seams: how?


Does anyone know a clear, efficient and well described technique available in UE4 to put rock meshes in a landscape and integrate them smoothly with it?
The idea is to have a result like this:

I found this video from a thread on polycount ( Following the discussion, no one really found a way to reproduce it in UE4.
But the post is almost 18 months old. So, maybe, since then, something new happened…

PS: someone on this thread mentionned an answer from Ryan Bruck’s on the answer hub (in june 2014), evoking a possible solution ( Problem is that it’s “evoking”: concretely, I just couldn’t figure out how to set this up in a scene.