Virtual Model Of 3D Urban Scene On Mobile Platform

Recent researches on information visualization and geographic navigation system like GIS (Geographic Information System), LBS (Location Based Service), etc, has diverted to new types of platforms as mobile devices and web services. Mobile environment has regarded as one of the academic and industrial issues based on the requests for mobility and flexibility. The new level of graphical technologies and performance on mobile device leads to create more powerful features in above mentioned systems. 3D primitives can provide more specific geographic information. In the three-dimensional model of the urban scene, a user can more directly match the models with the buildings and roads in the real world without any further mental conversion or translation to understand them.Although hardware resources are the main obstacle of developing mobile 3D graphics, but with optimized method, it is able to upgrade the graphic rendering performance. In this paper, the purpose of the research is to design and implement a three-dimensional framework of the urban scene walkthrough system based on the mobile hardware and software platform, and with optimized 3D modeling strategies which are suitable for resource-constrained embedded devices, to quickly and efficiently generate the three-dimensional models of the scene for mobile applications, as well as to provide mobile users with the visualization of 3D urban scenes information and space-based location services which are similar to those on the desktop environment, this article includes research on urban modeling based on JSR-184 specification and M3G standards, cameras and lights setting, building and exporting 3D scene tree, model re-generation on mobile devices, and the user interaction mechanism. The modeling method provided in this article integrated immediate mode and retain mode and its low computational complexity is an effective way to deal with the limited computing power of embedded processors, while the compromise made between graphics rendering quality and rendering time is the requirement of meeting the low-Memory capacity of embedded devices. It also put forward a traversable interface in the article in order for the system to be user-friendly and to allow one to explore the system from a pedestrian's angle, and be able to switch to a panoramic view, providing a full range of integrated information services.