Abstract: A method and a system for generating a building information model, in particular a BIM model, in order to work on the building, such as in the case of restoration work, for example. A two-dimensional, digitized building plan of the building is read in, wherein the building plan includes building objects and building object data assigned to the building objects. A scanning unit is used to acquire three-dimensional building data that are compared with the building plan. A building object in the building plan is detected based on the comparison data and the building object data of the building object are output. The building information model is generated from the three-dimensional building data and the detected building object and the building object data thereof are integrated into the building information model. The building information model is output for working on the building.