城市三维模型通用格式转换与可视化研究
Research on Universal Format Transformation and Visualization of Urban 3D Model

目前，城市三维模型有多种数据格式，格式间相互转换除了带来较高成本以外，还会导致模型部件信息与属性信息发生变化，以及模型精度损失等不足。3D tiles格式以其WebGL渲染机制为基础，能够实现海量三维数据的快速加载，因此被作为城市三维模型数据转换的目标格式和通用格式，但在实践过程中，其三维格式数据无法直接被获取，给模型的通用性带来一定阻碍。为此，本文以某县级市商品住宅小区为例，基于开源语言与工具，探索一套城市三维模型(IFC格式)向通用格式3D tiles转换解决方案与可视化优化研究，完成了坐标转换、空间索引构建、视域剔除，以解决城市三维模型在大规模应用中存在的使用成本较高、平台与数据不兼容等问题。
At present, many data formats were presented in three-dimensional urban models. In addition to high cost, conversion between formats will also result in changes in the information of model parts and attributes, and loss of model accuracy too. The 3D tiles format was based on its WebGL rendering mechanism and can realize fast loading of massive three-dimensional data. Therefore, it was the target format and common format for data conversion of the city three-dimensional model. However, its three-dimensional format data cannot be obtained directly in practice, which hinders the universality of the model. For this reason, based on the open source language and tools, this paper takes a commercial residential district in a county-level city as an example, and explored a set of technical process and solution for lossless transformation from the three-dimensional urban model (IFC format) to a universal format 3D tiles, coordinate conversion, spatial index and viewing frustum culling were completed during the conversion process, in order to solve the problems of high cost, incompatible platform and data in large-scale application of the three-dimensional urban model.