BIM and 3D City Models as Input for Microclimate Simulation

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Abstract

Climate change, and the effect it has on our lives and the world, has been at the centre of debate in the past decades. Also in architecture and urban planning fields, the effect of climate on buildings and cities has always had a role in the design process, nowadays especially when it comes to sustainability related topics. An interesting element within climate is the microclimate, which is a small area where climate circumstances are different then in the surrounding area. For example in an urban area the temperature difference between an area in a big city and the rural area around it can be up to 10°C, due to influences of surrounding buildings and materials. In the design process often more general weather data is used in calculation, this while they can differ a lot from reality. Modern tools make it possible to simulate the microclimate. One of these tools is ENVI-met. However, inputting 3D models into this software is mostly a manual process. This while a lot of information that is necessary is already available in existing architectural and urban design models. There is just no way to input this information into the software.

In this research a method is developed for combining detailed information from BIM models (IFC), with information about the surroundings from 3D City models (CityGML), and translating them to the ENVI-met format, so that these models can be used as input models for microclimate simulation in ENVI-met. This is done by creating a command line tool that extracts the necessary data from both input files, combining and converting it, and then writing it to a file in the ENVI-met format. Also guidelines and requirements for the input files will be established.

This is done by first establishing what information is necessary for microclimate simulation in ENVI-met and how this information needs to be represented, and then finding out where this information can be found in the intended input files, and how it is represented in there. From this can be concluded what information can be taken from which input file and the characteristics that are necessary for their correct use in the process can be established. Then the conversion tool itself can be developed, where the data is transformed to the same coordinate system and format, so that it can be combined and written to the ENVI-met format. In the last step the results are checked by doing a small case study and running the microclimate simulation.

This way, IFC and CityGML models can be used as input for microclimate simulation software ENVI-met, by using the conversion tool developed for this research and the provided guidelines.