For any external procedural work, Houdini Engine is the way to go. Houdini Engine in UE provides us with an almost real time preview of the generated heightfield right in the Unreal Engine viewport.
We have experimented with Houdini for heightmap generation. These textures are generally generated in an external DCC like World Creator, Gaea etc. Terrain generated from heightmap created in external DCC (Houdini) Unreal provides us with the option to import external height map textures and also masks for different terrain layers like snow, green fields, water, debris etc. Another viable solution is the use of heightmaps. However sculpting large-scale believable terrains is a time consuming process and you need a keen eye for how the terrain is formed in the real world. Terrain sculpting tools in UE4 provide a very smooth experience and with addition of alpha brushes you can get pretty realistic detail. When dealing with terrain in Unreal Engine we have several options.
