大型立交桥三维建模方法研究

立交桥是一个由桥梁、空间交叉和毗邻建筑物等组成的复杂空间结构,在整个城市道路网中占有很重要的地位。由于立交桥其自身的空间结构的复杂性,三维建模有异于一般建筑物和地形,尤其是对于大型的立交桥,其空间跨桥错综复杂、拓扑关系繁多,建模工作更为困难。在已有的数字城市模型中,大型立交桥的三维建模一直是个亟待解决的难题。该文从大型立交桥的三维数据模型与拓扑结构的组织管理入手,提出其三维建模方法的一般流程,以西直门立交桥为实例取得良好的建模效果,最后提出优化大型立交桥三维模型的一些关键技术。

A 3-Dimensional modeling method of complex and enormous cloverleaf junction

Cloverleaf junctions, which play an important role in city road network, are complex spatial structures composed of several bridges, spatial intersections and adjacent buildings.Because of the spatial structure's complexity, the modeling of cloverleaf junctions is quite different from general buildings and terrains.The modeling of complex and enormous cloverleaf junctions is especially difficult, for the complicated and involved spatial bestraddle, and the various topological structures.In existed 3-dimensional city models (3DCM), modeling of complex and enormous cloverleaf junctions is always a difficult problem to be solved.In this paper, authors have analyzed 3-dimensional data model and topological structure of cloverleaf junctions, developed a general modeling method to visualize cloverleaf junctions, and proposed the modeling flow.The Xizhimen cloverleaf junction is taken as the modeling sample, and a good result has gotten.Eventually, several key technologies and methods to optimize the 3-dimensional model of complex cloverleaf junctions are proposed.