More complex building regulations, a shortage of building land, and urban densification are making it increasingly difficult to submit an application for a building permit. In addition, the growing shortage of skilled workers means that the increasingly complex tasks can hardly be managed using the existing procedures. The growing information content makes it difficult to read the 2D site plan, which is still based on drawings and is an essential part of the planning application templates and demonstrates the integration of the building project into its building regulations and planning environment. At the same time, the planning process is being placed on completely new procedural and information technology foundations using the Building Information Modeling (BIM) method. BIM is object-oriented and geometrically 3D from the outset, so it makes sense to also place the site plan on a 3D basis. The basis for efficient data exchange between those involved in the planning process, including publicly appointed surveyors (ÖbVI), drafters (architectural firms), and approval authorities, must be a standardized data structure. A quality-assured 3D basis created with geodetic know-how in a standardized data structure is currently unavailable to the parties involved. More automation, particularly through model-based checks of complex regulations, can speed up the planning and approval processes and thus counteract the effects of the shortage of skilled workers. This is where the research project "3D site plan for building permit applications" comes in. The project aims to create an information model for 3D site plans that spans the BIM and GIS domains. The information will be the basis for interoperability between BIM and GIS-based processes, automating calculation and testing routines in the two domains, and incorporating the 3D site plan into the digital building permit process as an integral part. The presentation gives an overview of the current status of the project.