Export to Unreal Engine

World Machine is a popular terrain solution for UE4-based games, and the workflow is straightforward to take terrain and texture data from WM into UE.

The UE4 wiki has a very useful workflow guide from WM to UE4:

Our workflow guide and notes are listed below.

Within World Machine

1. Place a Height Output device into your world. Wire the terrain you wish export into the device’s input.You can also export a colormap by placing a Bitmap Output and connecting it appropriately.
2. Choose your export format within the File Output device. You should use the RAW16 format.
3. Determine your resolution. As noted in this document, Unreal Engine has some unique requirements for resolution of your heightfield.
4. Build your world and export all files. The “Export Terrain files…” option from the File Menu provides a central location to do both.

Within UE4

With the UE4 Landscape module, it’s even easier to import from World Machine. Simply enter Landscape Mode in the editor, and under the “Create New” tab, point UDK at the exported r16 file from World Machine. Make sure PC byte ordering and unsigned is selected.

Setup your terrain material weightmaps according to this tutorial:

Creating and Using Custom Heightmaps and Layers