3D Scene Streaming over P2P Network

• Main Authors: Ting-Hao Huang, 黃庭豪
• Other Authors: Bing-yu Chen
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/15092696220228399810

碩士 === 國立臺灣大學 === 資訊工程學研究所 === 95 === As the data size of 3D models increased, the data size of 3D scene also increased. The most relative example is 3D online games. The data size is so large that most of the game data are shipped using high capacity DVDs. However, to browse a large virtual world online, downloading the entire data is no option. In fact, only a small portion of the world is needed to render an acceptable result since most objects in a scene are to far to be seen, or hide behind opaque objects. To avoid the long waiting time of downloading the entire scene before browsing the virtual world, the concept of ”3D Scene Streaming” is proposed. Its general idea is: given the information of the scene and the position and viewing direction of the user, only objects which are seen, and will be seen in the future, are needed to be downloaded. The major question is to decide the priorities of the objects to be downloaded. To the best of our knowledge, there''re two approaches to achieve 3D scene streaming. The first one is view-dependent based approach, which considers the position of user, his/her viewing direction, and the distance between the user and object to decide the precedence of downloading 3D objects. The other approach is visibility preprocessing, which divide the entire scene into multiple cells and find the “potential viewable space” of any pair of cells. The former is quite suitable for outdoor scenes, but its efficiency may drop in indoor scenes because many objects near to user but occluded by opaque object are possible to be transferred earlier. On the other hand, the latter is very suitable for indoor scenes since architects usually designed following some rules such as symmetric. In this thesis, we adapt the view-dependent approach to achieve 3D streaming. In other words, we find the visual importance of each 3D object to decide their order of transmission. To address the scalability problem of traditional client-server network architecture, we separate 3D object into data pieces and apply FLoD for peer-to-peer network architecture. Experiment result shows that our system can display 3D scene with lowest quality loss under limited bandwidth, and the work load of server is reduced at the same time.