This is something I’ve been working on recently, first I tried World Machine but I wasn’t able to achieve the look I wanted so I switched to Blender. In blender I was able to procedurally generate a heightmap with distorted noise and then render it to a 4096x4096 PNG file. When first imported to UE4 the terrain is all blocky but with the smooth tool that can be fixed easily. The result is satisfactory, but there are a lot of shadow issues with the terrain and it’s pretty much impossible to get the sharp edges of real sand dunes with this method.
Let me know what you think, any advice or critique is appreciated!
Here’s some screenshots:
Download the .blend file here: https://www.mediafire.com/?bxvm2o3r653b95t
(Edit the heightmap until you’re happy with it then render it out at the size you want by making a material that uses the heightmap as a texture.)