A modular graph transformation rule set for IFC-to-CityGML conversion

Abstract

Conversion of Industry Foundation Classes (IFC) building models into CityGML city models is one of the operational scenarios for BIM–GIS integration, with a variety of applications producing and consuming data on either side. Given the in-depth cross-domain knowledge required to specify such conversions, the heterogeneity of the IFC input data and the use cases for the resulting CityGML, flexible and configurable solutions are needed that make conversion details accessible to domain specialists. Graph transformation as a conversion method fulfils these requirements. We propose to extend the modularity given by single transformation rules at a more coarse-grained level and identify four layers with modules of associated rules. We describe a self-contained set of rules across these modules and demonstrate its application to a range of building models.