A Workflow for Photogrammetric and Thermographic Surveys of Buildings with Drones

The interest in studying the energy performance of existing buildings has increased. Therefore, the integration of relevant information into BIM (Building Information Modelling) and BEM (Building Energy Modelling) is beneficial for energy information management and task automation. For an appropriate analysis of an existing building (“as-is”), it is possible to collect data on its 3D geometric properties and measure the thermal conditions of the building envelope to perform an energy analysis. The use of UAS (Unmanned Aircraft Systems)/drones has become a popular method for collecting building data because it offers advantages such as reduced labour, low cost, and easy access to locations that could not otherwise be reached. In addition, with the advancement of infrared (IR) sensors, which are getting smaller even smaller, it is possible to integrate them into drones. The IR data can be used to study building behaviour and pathologies, as different surface temperatures can be detected. Existing methods focus on fusing RGB (red–green–blue) and IR images, typically merging IR data with 3D geometry in a process that can later be integrated into BIM models. However, they do not achieve the advantages offered by this method with UAS and require additional equipment to perform the surveys. This paper presents a method for integrating building data obtained by photogrammetry and thermography into BIM environment, using only a UAS. In addition to this qualitative approach, a quantitative approach was developed using data collected by photogrammetry with the drone to perform an energy analysis of building envelopes.