Import CAD with Datasmith
Datasmith is the Unreal Engine CAD Importer. You can use it to add data to your map. You can find the list of supported file formats here.
For 3DS Max, SketchUp and Revit you need to install a plugin in the software and export the scene with the datasmith file format.
First you need to enable the Datasmith plugin (in the menu
The Datasmith button appears in the toolbar. Click on it to import a 3D model. You will get a datasmith scene actor in the World Outliner.
Finally you can try to convert the whole scene using the SkyReal Plugin.