The energy efficiency requirements at district scale revealed the need for detailed building energy simulations, with which the overall district energy demand can be estimated with an acceptable degree of accuracy. In order to meet this need, an automated simulation model generation process is introduced at the context of the European project OptEEmAL, which includes: a query stage where data are gathered from IFC, CityGML files, and a transformation stage where a single IDF file is generated for a building in a district environment, suitable for EnergyPlus simulations. The queried data are assumed to conform to certain correctness, completeness and consistency conditions across district and building scales. As a demonstration example, a simulation model is generated for a specific building. Future improvements of this work are discussed related to the integration of all the data requirements of the proposed process, in a District Data Model under an ontological framework.