Code, you need code some stuff.
If i wanted to import minencraft part of world i would do tihs:
- create per instance static mesh that can display different minencrraft cubes with textures.
- create cube to be used for instanced static mesh
- export minencraft part of world as locations and types of cube. All you need where box is and what are textures on it.
- make instanced static mesh actor that loads minencraft data and spawns cubes ith proper textures
No need to export and import whole geometry.