I had research lab exposure to what the US military had in the 80's, the groups I saw were hyper focused on 3D visualizations in support of in-the-field strategy. Think wireframes superimposed over a live camera feed, with those wireframes being the horizon line and what are the items beyond their current range of view. A building wall is simply a wireframe, and the floors and every type of sensor they could get to feed into visualizations to see inside and past buildings, hills, any navigable area.