It would be oh so super helpful if I could get the terrain Height and Weight maps back out of unreal Engine after making modifications. Often I need to use the landscape tools in Unreal Engine to clean up bad spots and artifacts on the terrain. it would be nice if I could get these changes back out of the engine and back in to World Machine. The only practical way I can see to do this is to have the ability to export the terrain back out as set of raw tiles just like we bring it in.
It’s possible -> take a look at the gizmo tool 
https://docs.unrealengine/latest/INT/Engine/Landscape/Editing/Gizmos/index.html