Based on Google's open-source Cartographer project, my team at the Senseable City Lab and I used two Velodyne VLP16 Lidar units to map the interiors of MIT's Lobby 7 and two train stations in Paris, as part of a sponsored lab project. I had the opportunity to work with lidar data, very sophisticated code written by Google engineers (which is innovative in its ability to do real-time loop closure), and ROS!
Below is a demonstration of Cartographer at work with data that we collected from one of Paris's famous train stations. My colleague and I actually pulled the above "Wall-E" dolly that we constructed for 2 hours in this train station. Can you guess which train station it is?