The overall framework of the proposed framework is shown in Fig. 1. First, a hybrid 3D LIDAR system
developed in this study simultaneously collects point clouds and temperature data from the envelope of existing
buildings. Temperature data are automatically fused with corresponding points during the data collection process.
After registering all individual thermal point clouds, a building envelope recognition algorithm will be applied to
automatically create an as-is BIM. The as-is BIM can be imported into energy analysis software through being saved
as an industry standard file format. Finally, the energy simulation results can provide the retrofit decision makers
more information to assist them on their decision making process.