## 4 The Development Prospect and Technological Breakthrough of DC
### DC 3D Modeling for Fine Management  
The progress of digital technology is dependent on the progression of the social economy. The development of the digital age promotes changes in social culture and changes people's living environment to some extent. Through the establishment of a 3D urban design visualization model, it strives to realize the real-time creation platform of 3D urban design scenes, provides the comparative spatial analysis of urban status quo and urban design, displays the full-size virtual roaming design scheme, and provides planning information analysis and query through the database. In this way, it can realize the creation, editing, and replacement of different architectural models in urban planning, providing a new evaluation method for urban planning evaluation, macro decision-making, and rational construction. [PERSON] and [PERSON] [105] suggested that the visual city management platform uses virtual reality technology to build a visual three-dimensional virtual simulation system of the city and realizes urban intelligent management with the help of data fusion and interconnection mechanisms. In SC progression, new digital technologies such as IoT, data analytics, and AI solutions are utilized in different urban verticals to support SC development [106; 107]. Dynamic digital technology is combined with static 3D modeling and DTs to expand the city for the understanding of temporal and spatial fluctuations. For the semantic city data model, the global CityGML standard is applied. CityGML is an open and standardized data model for storing and exchanging virtual 3D city models. For the live mesh model, data from existing aerial photographs, point cloud datasets, and laser scans are used. Finally, both the real grid model and the semantic city data model are published as open data for public use. The amount of data will increase more than 100 times compared to existing 2D GIS. Nevertheless, GIS itself is much worse than CAD and 3 DMax in 3D data modeling and visualization. Therefore, many scholars have constructed a 3D landscape model of the entire city by combining the advantages of these two systems and planned to use this model to manage the 3D information of the entire city, which was the beginning of the exploration of the 3D city model (3 DCM) [108; 109; 110]. Using the methods of aerial stereo image pairs and object extraction technology, the semiautomatic measurement of 3D data of aerial image houses is realized, and then the visible surface texture of buildings is restored on the basis of the ground and building surface two-dimensional semi-irregular triangulation network and original digital image, and the 3D urban landscape is reconstructed. Applying BIM technology to the 3D modeling of DC can simplify the building 3D modeling to the establishment of BIM database, and the 3D model established by using BIM technology is more accurate and more powerful. In addition, there are the following advantages: (i) BIM models are easy to obtain. The BIM model tends to replace architectural design drawings; that is, every new building must establish a BIM model to guide the construction of the project, which provides a strong guarantee for the source of the BIM model. The municipal government can establish special rules and regulations, ordering that new buildings must submit the BIM model to relevant departments for filing. This model can be imported into the 3D city model. (ii) Abundant model information. The BIM model contains abundant information, including building appearance, interior, material, and cost. If necessary, it can be imported into the 3D city model for users to query. In future DC construction, the integration of BIM data and 3 DCM data can promote the construction of 3D urban models. It can not only improve the model quality and schedule but also reduce the modeling cost and shorten the modeling schedule. The adoption of BIM technology in 3D modeling of DC is a new revolution in the progression of DC.