Caves in the terrain, possible?

[alexander.zubov]

From what I understood, Unigine's terrain is height map based.

 

I need to have caves in my terrain, some entrances into underground bunkers and whatnot.

 

How is it possible, if it is possible at all, to create that in the height map based terrain?

[frustum]

Create cave as a regular mesh and add a terrain hole in the editor.

[manguste]

There's also mesh_terrain_base material just for that purpose.