In the heart of Seoul's ever-evolving Gangnam district, a massive underground transformation is underway. Spanning 1.2 kilometers beneath one of the city's busiest urban corridors—from Bongeunsa Station (COEX Intersection) to Samsung Station—the Yeongdong-daero Underground Space Complex is a next-generation urban infrastructure initiative that combines mobility, sustainability, and spatial innovation.
When it's finished in 2028, the project will include a 21,000-square-meter underground transportation hub with integrated railroads and roadways, all buried up to 60 meters below the ground. On top of it all will be a large public park, creating a striking mix of a green space and the engineering marvel happening beneath.
Building this massive project requires incredible precision and a lot of data. To make sure every stage of the construction is perfect, a local surveying team used advanced 3D scanning technology from FJDynamics. The FJD smart scanners were used to track and record every detail of the work, creating a precise digital record. This helps the team keep an eye on the project's progress and ensures everything is built exactly as planned over the many years of the project.
Capturing Complex Data with FJD Trion S2 & P1
To document this huge underground project, the construction team utilized two LiDAR handheld scanners from FJDynamics: the Trion S2 and the Trion P1 . These scanners use SLAM to create detailed maps in real time without needing a GPS signal. This is a crucial feature, especially when working in deep tunnels and enclosed spaces where GPS doesn't work.Each scanner has a specific purpose. The Trion S2 can scan objects up to 120 meters away and is very precise, with an accuracy of about 1.2cm. This makes it perfect for mapping the larger, more open parts of the construction site. The Trion P1 is lighter and easier to carry. It scans up to 70 meters away with an accuracy of about 2cm, making it the ideal tool for tight spaces and detailed indoor areas.
The handheld design of both scanners makes them easy to use in small hallways, on stairwells, and in shafts. But for hard-to-reach places like high ceilings or deep pits, the team attached the scanners to the FJD extension pole. This allowed them to safely and accurately scan areas they couldn't reach on their own. With the simple accessory, the scanners were much more versatile and kept the workers safe while getting all the data they needed.
In addition, both scanners have a built-in panoramic camera. This camera does two important things: it lets the operator see what they're scanning in real time on their device, and it adds color to the 3D maps. After colorization, the data becomes much easier to understand and visualize. This makes it simpler for everyone on the team to collaborate and double-check the quality of the work, even when they're not on the job site.
Streamlined Post-Processing with Trion Model Software
After all the scanning was done, the team used Trion Model , a cloud point processing software from FJDynamics. The software helped them turn the raw scan data into useful 3D information for easier project management and reporting. Here are some of the features that impressed them the most:- Noise Filtering Tools: They can manually or semi-automatically remove unwanted objects from the scans, like scaffolding or temporary walls. This makes the maps much clearer and easier to analyze.
- Volume Calculation: They can quickly figure out how much material has been dug out or added to a certain area, which helps them track their progress on the project.
- Cross-Section Extraction: The software can quickly create horizontal and vertical cross-sections from 3D data, which can be exported into CAD or BIM formats for design programs. This is great for checking the work and creating reports.
- Deformation Analysis Support: By comparing scans taken at different times, the team can see if any parts of the structure have shifted or moved. The accuracy of this check depends on the quality of the scans.
Real-World Impact: Faster and Safer Underground Construction
By using the FJD Trion S2 and P1 handheld scanners together with the Trion Model software, the surveying team created a smooth field-to-office 3D scanning solution for the complex Yeongdong-daero project. This integrated approach allowed them to capture accurate and detailed 3D data in real time and then easily process it afterward.This powerful combination of hardware and software gave the team several key advantages. They could monitor the construction progress every month, from the ground level down into the deepest underground sections. They were also able to quickly spot any differences between the actual build and the original design plans. Finding these issues early helps prevent expensive mistakes and delays later in the project.
Beyond just monitoring, this solution also helped the team with safety and communication. It created detailed digital records that were easy to share for inspections and audits, and made the job safer by reducing the need for workers to take manual measurements in dangerous or hard-to-reach areas. The colorized 3D visualizations made it much easier for everyone involved—from contractors to engineers and clients—to understand the project's progress and stay on the same page.
A Smarter Way to Document Complex Construction
The Yeongdong-daero Underground Complex is a great example of how mobile 3D scanning technology is becoming essential for modern construction, especially in tough underground environments. By using handheld scanners like the Trion S2 and P1 with the Trion Model software, the construction teams can work smarter and safer. This combination of tools allows them to have a clear, digital view of the entire project, which makes it easier to manage, improves safety for workers, and keeps everyone informed at every step of the project.If you're interested in smart surveying tools or want to learn more about how FJD Trion technology works, please feel free to reach out to our dealers and distributors in your area, or just contact us directly here. We'll be happy to help and get back to you as soon as we can: Contact FDynamics