Blending meshes with landscapes with no seams: how?

Hi,

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 (http://polycount.com/discussion/148143/ue4-terrain-mesh-normal-blending). 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 (https://answers.unrealengine.com/questions/61109/how-do-you-manipulate-light-vectors-in-blueprints.html). Problem is that it’s “evoking”: concretely, I just couldn’t figure out how to set this up in a scene.