The increasing efforts in developing smart city concepts are often coupled with three-dimensional (3D) modeling of envisioned designs. Such conceptual designs and planning are multi-disciplinary in their nature. Realistic implementations must include existing urban structures for proper planning. The development of a participatory planning and presentation platform has several challenges from scene reconstruction to high-performance visualization, while keeping the fidelity of the designs. This study proposes a framework for the integrated representation of existing urban structures in CityGML LoD2 combined with a future city model in LoD3. The study area is located in Sahinbey Municipality, Gaziantep, Turkey. Existing city parts and the terrain were reconstructed using high-resolution aerial images, and the future city was designed in a CAD (computer-aided design) environment with a high level of detail. The models were integrated through a high-resolution digital terrain model. Various 3D modeling approaches together with model textures and semantic data were implemented and compared. A number of performance tuning methods for efficient representation and visualization were also investigated. The study shows that, although the object diversity and the level of detail in the city models increase, automatic reconstruction, dynamic updating, and high-performance web-based visualization of the models remain challenging.

中文翻译：

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异构3D城市模型的重构和高效可视化

开发智慧城市概念的工作量不断增加，而且往往与设想设计的三维（3D）建模结合在一起。这样的概念设计和计划本质上是多学科的。现实的实现必须包括现有的城市结构，以进行适当的规划。参与式计划和演示平台的开发在保持设计保真度的同时，还面临着从场景重建到高性能可视化的若干挑战。这项研究提出了一个框架，用于在CityGML LoD2中结合现有城市结构与LoD3中的未来城市模型进行综合表示。研究区域位于土耳其加济安泰普的萨欣贝市。现有的城市部分和地形是使用高分辨率的航空影像重建的，未来的城市在CAD（计算机辅助设计）环境中进行了详细设计。这些模型是通过高分辨率数字地形模型集成的。实施并比较了各种3D建模方法以及模型纹理和语义数据。还研究了许多用于有效表示和可视化的性能调整方法。研究表明，尽管城市模型中的对象多样性和详细程度有所提高，但是自动重建，动态更新以及基于网络的高性能可视化模型仍然具有挑战性。实施并比较了各种3D建模方法以及模型纹理和语义数据。还研究了许多用于有效表示和可视化的性能调整方法。研究表明，尽管城市模型中的对象多样性和详细程度有所提高，但是自动重建，动态更新以及基于模型的高性能基于Web的可视化仍然具有挑战性。实施并比较了各种3D建模方法以及模型纹理和语义数据。还研究了许多用于有效表示和可视化的性能调整方法。研究表明，尽管城市模型中的对象多样性和详细程度有所提高，但是自动重建，动态更新以及基于模型的高性能基于Web的可视化仍然具有挑战性。