Modeling and interactive rendering of urban environments

Abstract

Modeling and interactive rendering of urban environments are difficult as it is telling the story of simulating our real and complex world. Urban environment contains various buildings with different kinds of materials and different shapes, modeling such objects with conventional triangle mesh are not reasonable. It's not difficult to create the models, but to store and transmit the enormous data caused by the mesh models. Such amount of data is also very difficult to be put into computer memory for realtime rendering. Besides, roads and trees are also important parts of an urban environment. It is obvious that they share almost the same complexity of modeling and rendering with buildings due to similar problems. Therefore realtime interactive rendering with good visualization quality is very difficult to achieve. In this thesis, we are going to introduce various techniques for different objects in an urban environment to overcome mentioned problems. The first part of this thesis introduces a compact representation of urban building models called Non-uniform Texture, NUT for short. The representation is able to model a building with memory footprint more than two orders of magnitude smaller than that of its mesh counterpart, while impressive details and rendering performance are preserved. The second part introduces a compact representation of urban roads. The representation is also very efficient in data storage and memory consumption. Combing with NUT, the representation also offers great visual quality. The third part introduces an efficient rendering pipeline of trees. The pipeline requires no details to be stored to achieve data efficiency. The pipeline uses almost all functionality of mainstream GPU to provide stunning visual and rendering performance. The final part of this thesis introduces a robust computation of up vector, to solve the problem of camera rotation during video capture.

With all the mentioned features, we are going to produce a living urban environment within one system.