Besides CityGML, other standards and formats for 3D city models exist which are the result of, in the main, two kinds of applications: by the need of visualizations of 3D city models using computer graphics methods and in the fields of design, architecture and construction. For both kinds of applications, specific standards and formats are provided. These are reviewed in this section and compared to CityGML. Furthermore, the relationship to the prospective building model of the INSPIRE European initiative is examined and emphasized