3D City Models in Planning Activities: From a Theoretical Study to an Innovative Practical Application

Nowadays, the employment of digital 3D city models is rapidly growing in a variety of research fields since for a city administration being equipped with digital spatial data is an advantage for a large spectrum of applications related to city’s planning and management. For this reason, 3D city models today represent effective support tools used in a wide variety of purposes, which range from analysis and development of a city, to citizens’ communication and engagement. However the increasing number of different applications that employ 3D city models, where each of them requires its own specific level-of-detail (LoD) has lead to a fuzzy vision about the real possibilities of utilization that 3D city models have. In light of that, the aim of this paper is to provide a general overview about the current fields of application of 3D city models, in order to classify the 3D data requirements to specific applications, clarifying which types of 3D models with certain features fit-for-purpose. Successively, an example of practical application is displayed in the Swedish environment, where a 3D building model was developed for the municipality of Vaxholm, in the Stockholm County. In conclusion, pro and cons about the results achieved, have been described, on the one hand, providing a hypothetical procedure that might be used to build a 3D city model within a certain set of data formats, and on the other hand, considering the analysis of different fields of application, forecasting likely improvements and future purposes to which the 3D building model generated might be extended. This kind of Virtual Reality is therefore available for applications of participatory democracy, to promote forms of collaboration and learning in citizens and students.