Book excerpt: In recent years 3D geo-information has become an important research area due to the increased complexity of tasks in many geo-scientific applications, such as sustainable urban planning and development, civil engineering, risk and disaster management and environmental monitoring. Moreover, a paradigm of cross-application merging and integrating of 3D data is observed. The problems and challenges facing today’s 3D software, generally application-oriented, focus almost exclusively on 3D data transportability issues – the ability to use data originally developed in one modelling/visualisation system in other and vice versa. Tools for elaborated 3D analysis, simulation and prediction are either missing or, when available, dedicated to specific tasks. In order to respond to this increased demand, a new type of system has to be developed. A fully developed 3D geo-information system should be able to manage 3D geometry and topology, to integrate 3D geometry and thematic information, to analyze both spatial and topological relationships, and to present the data in a suitable form. In addition to the simple geometry types like point line and polygon, a large variety of parametric representations, freeform curves and surfaces or sweep shapes have to be supported. Approaches for seamless conversion between 3D raster and 3D vector representations should be available, they should allow analysis of a representation most suitable for a specific application.