This article focuses on 3D indoor modelling of buildings using cadastral data as an alternative way of indoor spatial data acquisition. Despite the rapid development of indoor spatial data acquisition technology, there are no existing solutions that would enable mass acquisition of indoor data. The main motivation for our research was the general difficulty of indoor spatial data acquisition and consequently modelling, which is needed in particular for the purpose of indoor location-based services, while there is a large amount of cadastral data available that can be used for 3D indoor modelling. For the case study, we chose the Slovenian Building Cadastre, which provides a technical basis for condominium establishment and is the only centrally maintained and accessible database that contains data about building interior structure in Slovenia. We designed a framework for 3D indoor modelling based on cadastral data, comprised of a chain of processes, starting from initial cadastral data and ending with the IndoorGML document. The OGC IndoorGML standard is used for final outputs, as it provides a standardized data model for the representation and exchange of indoor spatial information designed for indoor navigation and location-based services. The process chain consists of three main parts, which are described in detail and summed up in a flowchart diagram. Our aim has been to design each process in the most generic way as possible, while also considering the particularities of Slovenian cadastral data. The proposed approach is software independent and can be implemented using various spatially enabled software packages. The study provides a good example of the cadastral data usefulness for 3D indoor modelling for Slovenia and can be used in many countries having a similar condominium registration system, i. e. land administration.