In this interactive talk, we explain how we used the Flemish open Lidar data. In the first part of the talk, we give an introduction about Lidar data, and explain in human language how we build 3D models for each house in Flanders. In the second part of the talk we touch the business model of Rockestate, and explain how we combine these 3D models with other open data and build predictive data driven models for banks, insurers and retail energy suppliers.