3D-City Modeling: A Semi-automatic Framework for Integrating Different Terrain Models

In recent years, many systems have been developed to handle realtime rendering of a 3D-city model and its terrain. These terrains are often constructed using one of the two main methods for representing terrain e.g. Image-based or geometry-based terrains. Both of these methods have its advantages and disadvantages, which are presented in this paper. However, by combining these methods and their advantages a more efficient modeling tool can be achieved. This paper presents a framework of how these two techniques can be linked and integrated by usage of the Graphics Processing Unit(GPU), which result in a user-friendlier and more efficient modeling process of terrain. The main objective with our framework is to address the difficulty of integrating a 3D model of a planned building with its surrounding ground, into a 3D-city model. Furthermore, the framework is also applicable on general3D models that address the same issues regarding integration of 3D models into a terrain model