Here is a material i was working on for my graduation project at Supinfogame. I was inspired by the the 2016 GDC talk by Dice about Star Wars Battlefront to blend Meshes into the landscape. I also learnt a lot from Olmo on his polycount post (link down below) for the distance field. There is 2 materials, one with displacement to create a smooth curve on connection edges and one without.
You can fin this material for free right here : https://gum.co/BVVFy
Don't forget to have 'Generate Mesh Distance Fields' in your project setting enabled and also uncheck "Affect Distance Field" on your Static Mesh to make it work.
Feel free to comment, enjoy !
Substances made by Romain Pommier : https://www.artstation.com/artist/romainpommier
Olmo's post : http://polycount.com/discussion/181140/unreal-4-terrain-blending-tool-inspired-by-star-wars-battlefront