Automation process in data collection for representing façades in building models as part of the renovation process

A key barrier in building façade renovation processes versus new designs is that an initial building model on which the design process is based rarely exists and that the technologies usually employed to create it (e.g., based on point cloud scanning) are costly or require modelling skills. This situation is a clear limitation, especially in early decision stages, where the level of detail required is not very high and the analysis and studies to consider the renovation plan (e.g., simplified energy simulations and renovation potential, or estimation of the number, types, and dimensions of the prefabricated modules incorporating solar panels) highly depend on such digital models. This paper introduces a process that, based on freely available data such as open GIS sources (local cadasters, OpenStreetMap…) and façade images, can semi-automatically generate the 3D building model of the existing conditions and, in a second step, can also suggest the prefabricated façades module layout for building upgrades. Additionally, no on-site visit is needed. When the upgrade is focused on the façade, a big opportunity is identified for generating the building model and a realistic representation of its envelope, only using online data sources as input. The process developed consists of a set of easy-to-use software tools that can be used independently or combined in a workflow, depending on the available data and starting conditions. Time-saving is the main benefit, which also contributes to reducing costs.