A MODEL-DRIVEN APPROACH TO THE INTEGRATION OF PRODUCT MODELS INTO CROSS-DOMAIN ANALYSES

During the many phases in the lifecycle of a building, an ever growing number of dynamic and static aspects are encountered that seem worthy of modelling in a computer-readable representation. Product models that attempt to cover the concepts from the many disciplines or phases in a product's lifecycle face a dilemma, namely maintaining a balance between growing model complexity on the one hand, and user requests for additional concept coverage on the other. In examining the main principles of model theory (Stachowiak 1973) more closely, this paper tries to identify tendencies that may hamper the balance between complexity and completeness. However, a scientific evaluation of model complexity needs objective measures. Metrics for the assessment of software complexity are readily available and can also be applied to models, since models (schema or instance) can automatically be transformed into a programming language (Hartmann, von Both 2010) or an instance structure. These metrics can therefore be helpful in the discussion about model complexity. Different approaches have been taken to handling model complexity and the complex process of modelling itself. Leal S. et al. (2014) develop a template-based model generating tool for energy simulation models to evade the lossy and complex recourse to IFC or gbXML models. Cao J. et al. (2014) use a transformation tool to generate building energy performance simulation models in order to reduce the complexity otherwise encountered in traditional building simulation programs. Thomas D. et al (2014) combine a CitySim model holding a simplified representation of the surrounding buildings with models for the EnergyPlus building performance engine. This allows for rapid assessment of the performance of the early design-stage building information models (BIM) on both the building and urban systems scale. Koene F. et al. (2014) take the reductionist idea of model theory a step further by reducing a building to a simple model consisting of two thermal masses. The Building Lifecycle Management Department at Karlsruhe Institute of Technology KIT conducts analyses beyond the scope of a single building. Analyses often have to take the urban environment into account, meaning that not only building models but also models of the surrounding city area are potentially involved. From the modelling standpoint this raises the question as to whether the city model and building models should be unified into one "super model", or whether models should be kept separate and the relations between them expressed by means of meta data. The work presented is a result of the research project "A model-driven approach to the integration of product models into cross-domain analysis processes" (original title: "Ein modellgetriebener Ansatz zur Integration von Produktmodellen in domanenubergreifende Analyseprozesse") sponsored by the federal German research funding organization 'Deutsche Forschungsgemeinschaft (DFG)'.