Digital Twin Visualization

Digital Twin Visualization 

Digital Twins provide a virtual replica of real-world assets and their surroundings. They offer numerous benefits across various sectors, including Digital Twin technology for the construction sector. However, many users lack insight into the process of Digital Twin creation.  

In this series, we aim to bridge this gap by providing insights into the creation of a Digital Twin. Whereas the previous article was about the Digital Twin data core and Digital Twin Requirements, this article will provide insights into the Digital Twin visualization. Get inspired now!  

Digital Twin Map Viewer 

In the previous series we gathered the necessary data and set up the required services to make the data accessible. Everything is set for rolling out the Digital Twin user portal. Because our data core follows open standards, it can connect with various map visualization platforms. Map visualizations are a powerful way to present geospatial data. The possibilities to do this in 3D are also continuously improving. In the end we want to get a full 3D model for our Digital Twin. Here we name a few important map viewers.  

• We use CesiumJS a lot for creating immersive 3D maps and globes that run in the browser. CesiumJS is the core software of the Sogelink Digital Twin front-end platform to create the base canvas that integrates both 2D and 3D geospatial data.  

• Other mapping libraries may also have 3D capabilities. For example, MapLibre, is useful for interactive maps, especially when complex 3D features aren’t necessary, and it performs exceptionally well with 2D and vector data. 

3D Digital Twin technology 

As a user, you want an optimized Digital Twin visualization in 3D. An important standard for optimized 3D data visualization is the OGC 3D Tiles standard. OGC 3D Tiles is an open standard for streaming massive 3D geospatial datasets over the internet. Developed by the Cesium team and endorsed by the OGC, this standard efficiently organizes and transmits large-scale 3D datasets. The standard enables the following types of data to be loaded into our Digital Twin: 

• Instanced 3D Models: Instanced 3D Models involve duplications or repetitions of a single 3D model. This technique is commonly used for objects with consistent shapes like streetlights or trees. For this purpose, we’ve created i3dm.export, a tool to convert locations from a PostgreSQL database to the instanced 3D Tiles format. 

• Point Clouds: Point clouds are collections of 3D points that represent the shape of an object or area. Point clouds are generated by LiDAR scanners or through photogrammetry. Point clouds may be stored in various file formats. Converting point clouds to 3D Tiles can be done by using tools like GoCesiumTiler or Oslandia’s py3dtiles. 
• GLB/glTF: 3D Tiles are built on GLB/glTF files. GLB (GL Binary) and glTF (GL Transmission Format) are open file formats. These file formats, maintained by the Khronos Group, are widely used in computer graphics, 3D modeling, and virtual/augmented reality applications. 

Digital Twin 3D Terrain 

Terrain is an important aspect in a geospatial 3D Digital Twin model. The basis for generating a terrain is a Digital Elevation Model (DEM). The elevation data often requires  preprocessing to address gaps, such as those caused by water bodies, or other irregularities. Some methods to use this data to create a 3D terrain are: 

• Quantized mesh: One method to represent DEMs’ is by converting them into triangulated 3D meshes. Quantized 3D meshes, in particular, are optimized for streaming massive terrain data to web browsers. Cesium Terrain Builder is a valuable tool for converting DEMs into such quantized terrain meshes from GeoTIFF files. 
• Cesium Terrain on Demand: Terrain data can be huge in size, especially when applying Digital Twinning on a national or regional level. To prevent the need to store and process large terrain datasets in advance, Sogelink developed Cesium Terrain on Demand (CTOD). This web service generates quantized mesh terrain tiles on-the-fly from a Cloud Optimized GeoTIFF (COG). It does so dynamically and only when needed depending on the viewpoint of the user. 

Key Takeaways 

• The Digital Twin user portal allows users to interact directly with the data, models and analytical tools. By using open standards and powered by map visualization tools like CesiumJS and MapLibre, it enables 3D Digital Twin representation with dynamic functionalities.  

• The OGC 3D Tiles standard optimizes 3D data visualization of Digital Twins, enabling the streaming of massive geospatial datasets. Developed by the Cesium team and backed by the OGC, this standard allows for efficiently organizing and streaming large-scale 3D datasets. By Using Batched 3D Models, Instanced 3D Models, Point Clouds, and GLB/glTF files, and WebGL, Digital Twin visualizations achieve a high quality. 

• 3D Terrain is important for realistic geospatial Digital Twin visualizations. The basis for generating a 3D terrain are Digital Elevation Models (DEM). 

FAQ 

• What are the benefits of Digital Twin visualizations? Digital Twin visualizations offer users improved insights for enhanced decision-making, and better understanding of complex systems and environments. 

• How do you create a Digital Twin visualization? Creating a Digital Twin visualization involves gathering necessary data, setting up services, and employing visualization tools to present geospatial data effectively. 

•  How is the 3D data prepared for the Digital Twin visualization?  3D Tiles is a standard for efficiently visualizing 3D data, including support for object instancing and large point clouds. 3D data is converted into 3D Tiles to be able to visualize Digital Twin on a national or even international scale. 

• What is the importance of 3D Terrain in Digital Twin visualization? 3D Terrain, based on Digital Elevation Models (DEMs), forms the foundation for realistic environments. Quantized mesh technology and tools like Cesium Terrain on Demand facilitate the efficient handling and streaming of large-scale terrain data. 

Visit our Digital Twin FAQ page for more frequently asked questions about Digital Twins. Next to that, here you find more information about the Digital Twin concept as a whole.