Goal: The main goal of the research project is on using AI and cloud technologies for the construction industry as key technologies in the retrodigitization of existing buildings. Information on buildings and infrastructure structures, e.g. 2D plans, images, point clouds or text documents, is to be evaluated by means of AI processes, structural and technical construction elements are generated and consistently and transparently fed into a BIM-based as-built model. Similarly, the updating of an existing as-built model is to be automated. The data and AI services will be provided in a decentralized manner using open standards and existing BIM systems based on GAIA-X. An ecosystem is created which forms a fundamental basis for BIM applications.