A Must-Read for Construction Managers! New Norms in As-built Management Transformed by 3D Scanning

In construction and civil engineering sites, 3D scanning (point cloud measurement) for three-dimensional surveying is becoming the new norm in construction management. 3D scanning is a technique that records site topography and structures as data composed of countless points (point clouds) using lasers or photogrammetry. The acquired point clouds have X, Y, and Z coordinate values, and the denser the point cloud, the more faithfully the real object can be digitally reproduced with millimeter-level (0.04 in) precision. Advances in positioning technology in recent years have brought this high-precision 3D scanning into practical use, and initiatives such as the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction promotion have further accelerated its rapid adoption. The era in which “anyone can easily,” “use precise 3D data,” and “do so instantly on site” is at hand, and this is beginning to greatly contribute to improved productivity and advanced quality control at construction sites.

This article focuses on as-built management (verification and recording of shape and dimensions after construction), explaining differences from traditional methods, the advantages of introducing 3D scanning, and practical use cases and operational steps for the latest point cloud measurement tool anyone can use on a smartphone, “LRTK.” Let’s look at the forefront of construction management where traditional norms are changing.

What Is As-built Management? Challenges of Traditional Methods

First, let’s confirm what as-built management is. In civil engineering and construction, as-built management is the construction management process of verifying and recording that the shapes and dimensions of completed structures and developed land conform to the design. Especially in public works, it is necessary to prove with measured data that construction was carried out according to design based on the as-built management standards specified by the client. It is common practice to measure designated locations at the completion of each work type (for example, immediately after concrete placement or before backfilling), check whether deviations from specified values are within allowable ranges, and compile the results into record drawings and forms.

Traditional as-built measurement mainly involved manual point-by-point measurement using tape measures, scales, staff rods, levels (survey instruments), and the like. For example, in road works, heights, widths, and thicknesses of the roadbed or pavement would be measured at several dozen points after completion and compared to drawings. However, this method had several issues. First, because it requires manpower and time, the number of measurement points is limited. As a result, only key points of the construction are measured, and the overall shape of the structure cannot be fully grasped. The lack of comprehensiveness means there is a risk of overlooking design deviations outside the checked points. Even if key points pass inspection, subtle unevenness or dimensional excesses in other areas may be discovered in later inspections. Furthermore, manual measurement entails the possibility of human error. Forgetting to take photos, transcription mistakes, or misaligned measurement references can undermine the reliability of quality certification. In large structures or works involving buried elements, manual measurement alone is especially limited, and the longstanding problems have been the omissions and heavy workload caused by being able to measure only at points.

Benefits of Introducing 3D Scanning

To address these issues in as-built management, measurements using three-dimensional point cloud data are gaining attention. By scanning the entire site and recording it as a point cloud, even minute differences that were previously overlooked can be identified. Let’s look at the main benefits that introducing 3D scanning brings to construction management.

• Dramatic improvement in accuracy and comprehensiveness: Point cloud measurement can record the shapes of structures and terrain without omission. Areas that could only be measured at a few points manually can be captured in planar and volumetric detail, significantly improving as-built management accuracy. Millimeter-level (0.04 in) surface irregularities and dimensional differences can be detected, so even small excesses or shortages are not missed. If concrete interiors or areas around buried pipes that would normally be hidden after construction are recorded in 3D immediately after construction, they can also serve as future quality evidence.

• Reduction of work time and increased efficiency: Using 3D laser scanners or drone photogrammetry, wide areas of as-built conditions can be acquired in a single measurement. Inspections that used to take a full day with multiple people can, in some cases, be completed in a few hours with a laser scanner. In fact, a survey by the Ministry of Land, Infrastructure, Transport and Tourism reported that the use of ICT construction (3D surveying, machine guidance, etc.) reduced total earthwork man-hours by an average of about 30%. Being able to acquire large amounts of point cloud data at once greatly reduces rework surveying, directly shortening overall schedules and improving productivity. Automated processing by analysis software also streamlines previously manual quantity calculations and drawing creation, speeding up as-built inspection tasks themselves.

• Labor savings and improved safety: Point cloud measurement can be operated by a small team, and in some cases a novice can handle the equipment alone. Survey and inspection work that used to require a team including veterans can be downsized, helping to alleviate chronic labor shortages. Because measurement can be done remotely and without contact, inspectors do not need to enter hazardous areas such as heights, steep slopes, or busy roads. For example, since measurements can be taken by simply directing a laser from a distance, the need to erect scaffolding or use aerial work platforms is reduced. This leads to better worker safety and a reduction in accident risk.

• Digital records and data utilization: Acquired point cloud data can be stored and shared in the cloud, creating valuable digital records for the future. Point clouds allow free viewpoint changes for inspection and enable cutting additional sections or remeasuring dimensions later as needed. Information that could only be kept two-dimensionally in paper drawings or photo albums can be preserved in three dimensions with point clouds. Sharing data among stakeholders enables remote inspections where clients or inspectors can verify and approve as-built conditions from afar. Always having up-to-date site data in the cloud reduces miscommunication and smooths reporting and discussions. Submission of three-dimensional data in electronic deliveries is also becoming mainstream, and centralized data management will be useful for future maintenance and knowledge transfer.

As described above, introducing 3D scanning makes “more accurate, faster, safer, and more efficient” as-built management possible. The dramatic labor savings and improved ability to prove quality make this a fundamentally different new norm from traditional methods. Next, let’s look at concrete examples of how 3D scanning is used in construction management tasks.

How 3D Scanning Is Changing Construction Management on Site: Use Cases

Point cloud data exerts its power in many aspects of construction management beyond as-built control. Here are representative tasks such as surveying, as-built inspection, and quantity/progress measurement where 3D scanning is used.

• Speeding up site surveys: For pre-construction topographic surveys, creating point cloud models from drone aerial photos allows detailed terrain over wide areas to be acquired in a short time. Mountainous surveys that would take days manually have been completed in about half a day in some cases. From the acquired high-density point clouds, contour maps and cross-sections can be created at will, directly improving the accuracy of earthwork volume calculations and schedule planning during design. Once a point cloud is taken, additional cross-sections can be cut later, preventing re-visits to the site due to “forgotten measurements.”

• Advancing as-built inspections: For post-construction as-built verification, methods have emerged that digitally compare point cloud data with design drawings or 3D design models. Traditionally, differences from design values were checked at individual measured points, but with point clouds you can overlay the entire current state and design data for surface comparison. Typical methods include cross-section comparisons between the finished and planned shapes and height-deviation heat maps color-coded on the point cloud. For example, in riverbank revetment slope works, as-built point clouds are used to check slopes and thicknesses in cross-sections and immediately issue corrective instructions for areas outside tolerances. Digital data enables quality control approaching full-quantity inspection, allowing early detection and response to defects that manual measurements may have missed.

• Streamlining earthwork volume calculation and progress management: Point cloud data is useful not only for shape confirmation but also for managing earthwork quantities and progress. Scanning the ground surface before and after construction enables automatic calculation of excavation and fill volumes from the differences. Because it can reflect subtle irregularities across the terrain, it allows higher-precision volume calculation than conventional cross-section or grid methods. Once a point cloud is obtained, volume calculations for different sections or additional re-calculations can be done immediately at the desk. In one large-scale land development site that introduced drone photogrammetry, a volume measurement that had previously taken 4 people × 7 days was completed by 2 people × 1 day, reducing personnel and days to about 1/14. Despite this, the calculation error was nearly the same as conventional methods, demonstrating both efficiency gains and accuracy maintenance. 3D scanning–based quantity management also speeds up progress tracking and quantity acceptance, contributing to shorter schedules and cost reductions.

• Visualization and verification through AR technology: Recently, augmented reality (AR) using smartphones and tablets has begun to be used on construction sites. With AR functions, you can overlay a 3D design model onto the site camera image to intuitively visualize discrepancies between the actual object and the design. For example, on bridge works you can project a completed 3D model on site to check whether steel frames or bolt positions match drawings by comparing them directly with the actual structure. In paving works, CAD design data can be displayed in AR to visually confirm finished heights and make on-the-spot decisions about rework if necessary. Being able to composite the finished image into the real scene also aids explanations and consensus-building with clients or owners, as the completion image that is hard to convey with drawings alone can be shown overlaid on the actual view.

As shown above, 3D scanning and related digital technologies are transforming sites widely—from surveying to as-built inspection, quantity management, and visualization of construction. What if such advanced measurement could be easily performed by anyone on site? In the next chapter, we introduce the groundbreaking solution that lowers this barrier: “LRTK.”

Simple 3D Measurement for Everyone with Smartphone × GNSS: The Arrival of LRTK

While the usefulness of 3D scanning has become clear, some companies hesitated to adopt it due to the issues that “high-performance 3D laser scanners and surveying drones are expensive and require specialists.” Especially for small and medium-sized construction firms and regional sites, the cost of equipping the latest gear and the hurdle of training operators are real problems. Amid this, a new technology combining a smartphone and a compact GNSS receiver has emerged, rapidly changing the situation. A representative example is “LRTK,” a palm-sized device that turns a smartphone into a high-precision positioning device and 3D scanner.

LRTK consists of an antenna-type device that attaches to a smartphone and a dedicated app, forming a modern positioning and measurement tool. With real-time RTK-GNSS positioning, a smartphone can obtain centimeter-level (half-inch accuracy) high-precision position information, and by using the smartphone camera or LiDAR to perform point cloud scanning as well, you can acquire 3D point cloud data with absolute coordinates on the spot. Without expensive dedicated equipment, your existing smartphone instantly becomes a “high-precision 3D scanner.”

The merits of LRTK are very clear. First is its ease of use and versatility. Unlike heavy static laser scanners, a smartphone + LRTK is portable and quick to prepare. It offers flexibility to scan in confined indoor spaces, tunnels, underground pits, and even during night work—anytime, anywhere. Also, unlike drones, it does not require flight permission applications or suffer from weather constraints, so you can start measuring the moment you decide. The low initial cost is another important point. Because you only add a device to an existing smartphone, it is far cheaper than purchasing a high-priced laser scanner or surveying instrument. Renting or subscribing also makes it easier for small sites to introduce the latest technology.

Furthermore, LRTK supports Japan’s high-precision satellite positioning service “Michibiki” CLAS, so it can receive correction information directly from satellites and maintain centimeter-level (half-inch accuracy) precision even in satellite coverage-limited mountainous or maritime sites. Stable high-precision positioning is possible even in environments where network connection is difficult, making this a technological innovation that truly enables “anyone, anywhere, anytime” precise 3D scanning. The emergence of such an easy solution has significantly lowered the barrier to point cloud utilization. In fact, the LRTK series is compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and is attracting attention as a means to accelerate DX in the construction industry.

LRTK Use Cases: On-site Effects of Adoption

So, what concrete effects can be obtained by introducing LRTK on-site? Here are examples of actual use scenes.

• On-the-spot verification of conformity to design in riverbank revetment works: In a riverbank revetment project, as-built point clouds acquired with LRTK were overlaid with the design 3D model for as-built management. Work that previously involved measuring key points after completion and comparing them to drawings could now be fully checked on the 3D point cloud, eliminating gaps in quality control. Using the AR function in the LRTK app, the design model was projected onto the real scene on site to confirm finished positions, which smoothed explanations to the client and alignment among site staff. Because the 3D model can be visualized on site, it becomes immediately clear “where and how much the drawing and the as-built differ,” and locations needing correction can be shared and addressed at once. Introducing LRTK thus dramatically improved both as-built inspection and consensus-building processes.

• Optimizing dump truck arrangements by immediate spoil volume measurement: At another civil engineering site, spoil piles generated by excavation were scanned with LRTK and volumes were calculated on the spot to improve the schedule. The site agent walked around the spoil with a smartphone to capture the point cloud, and the cloud-calculated volume values in the cloud were used to instantly determine the number of dump trucks required. Previously, volume calculations were done back at the office after site surveys, taking more than half a day, but this process was completed with just a few minutes of scanning. Daily progress volumes could be grasped immediately, enabling optimization of heavy equipment operation plans and reducing truck waiting time. In this case, enabling the site person in charge to measure and decide immediately resulted in significant speeding up of decision-making and waste reduction.

As these examples show, introducing mobile point cloud measurement tools like LRTK transforms on-site decision-making and work cycles. Being able to acquire and utilize high-precision site data in real time makes it possible to achieve both quality assurance and efficiency.

Steps for LRTK Implementation and Operation

So how should you proceed to actually use LRTK? Here are the typical steps to start 3D scanning–based as-built management using LRTK.

• Prepare equipment and app: First, prepare the LRTK device itself, a compatible smartphone, and the dedicated app. Attach the device to the smartphone and perform account registration and initial settings within the app. Contracting and setting up positioning services (GNSS correction information) should also be done at this stage. The setup itself is simple, and in a matter of tens of minutes you can be ready for on-site measurement.

• Positioning and scanning on site: At the site you want to measure, start LRTK and first perform positioning of control points or alignment to known points as needed. Then, holding the smartphone, walk around the target while scanning to capture point cloud data. Pausing at key points and turning around helps capture data without blind spots. For wide areas, scan multiple sub-areas and merge the point clouds later. LRTK automatically attaches high-precision coordinates while shooting, so anyone can obtain stable-accuracy point clouds without special surveying skills.

• Data synchronization and cloud upload: After scanning is complete, upload the point cloud data to the cloud from the app. Using the LRTK cloud, data captured on the smartphone is instantly synced with the office PC. Large-volume data can be shared smoothly over the internet, eliminating the need to return from site and connect cables. Point clouds uploaded to the cloud undergo initial processing such as automatic alignment and noise removal, making them ready for the next steps.

• Analysis and comparison of as-built data: Analyze and compare the uploaded point cloud data with various tools. Specifically, overlay design drawings or 3D models on a point cloud viewer to check as-built conditions, create cross-sections and measure dimensions. LRTK cloud also has browser-based functions to measure distances, areas, and volumes, so basic as-built inspections are possible without specialized software. Features such as height-deviation heat map visualization to color-code differences from design make intuitive quality evaluation possible even for point cloud beginners. Use the report output function as needed to compile inspection results into figures and tables.

• Sharing results, reporting, and use in subsequent processes: Share and utilize the analyzed as-built data with stakeholders. You can publish data in the cloud and share links so that clients or supervisors can verify and approve as-built conditions remotely. On site, if needed, you can overlay point cloud data and design models on tablets or AR glasses to confirm as-built conditions in the real scene and issue correction instructions. Finally, organize digital as-built data as delivery materials and submit them to electronic delivery systems. The acquired 3D data becomes an asset for future maintenance and construction records. Accumulate it within the company for use as reference data for the next site or training materials for new staff.

These are the basic operational flows. It may seem difficult at first glance, but LRTK is designed so that you can obtain and use as-built data intuitively without expert knowledge in surveying or point cloud processing. If site staff can lead digital measurement operations, substantial efficiency gains and quality improvements are expected.

Conclusion: Toward the Next Generation of Construction Management with 3D Scanning

The spread of 3D scanning technology is dramatically changing the norms of construction management, including as-built control. High-precision quality control through full-coverage measurement that was impossible with traditional methods, and overwhelming labor savings leading to productivity improvements, have become possible with digital measurement. And with tools like LRTK that can be used on smartphones, the latest technologies are becoming accessible to everyone.

In an industry facing chronic labor shortages and the need to respond to work-style reforms, digital utilization beyond conventional norms is the key to opening the future of the field. Embrace the new norm that “as-built conditions are measured by point clouds” and “the entire site is digitally recorded and shared,” and take a step forward. As a first step, why not consider introducing a high-precision 3D measurement tool? Easy-to-use solutions such as LRTK will surely strongly support your site’s DX promotion.

※ For more details, please also visit the [LRTK official site](https://www.lrtk.lefixea.com/). Case studies and product information are published there, and you can learn more about the “3D scanning anyone can do” made possible by cutting-edge positioning technology. Use the latest technology to evolve your site into the next generation of construction management.