The Study On Modeling Theory And Development Technique For City Building In 3D GIS

The informatization of the city has provided an opportunity for development and innovation of a city. Informatization construction aimed to build the "digital city". The 3D City Model can express spatial information of a city truly and vividly, meanwhile it made a qualitative change in the expression mode of city construction currently and design and urban planning in future. As a core of 3D City Model, 3D building model has already attracted more and more attention. How to construct the 3D building detail model and realize the 3D GIS service in World Wide Web has become one of the hotspot in this field.In this paper, On the basis of the analyzing the apply of GIS city building 3D model and the software such as CAD 3DS Max and Web3D ,we adopted the method of the modeling entity model , and decomposed the city building to typical entity parts. With the geometric constraints between entities the author has built the 3D detail model of city single building atlast. The contents and conclusions of the study are reported as following:1) The modeling method of 3D city model was studied. With the using of the MAXScript language in modeling assembly, the method of assembly modeling of building single with 3D geometric constraints was put forward. 2) By analyzing virtual reality technique, the realization method of virtual walkthrough which include 3D scene modeling and scene optimize was explored.3) The effect of Web3D technique on virtual walkthrough system on webs was discussed. With virtual reality development platform-Virtools, the virtual walkthrough system on web was realized .