Reduce Costs with Point Cloud As-Built Management! Easy Implementation for High-Accuracy Data Utilization!

Cost Issues in Field Surveying and the Potential of Point Cloud Data

As-built management (the work of confirming and recording whether the shape and dimensions of completed structures after construction match the design) is indispensable on construction sites. However, traditional as-built management is labor- and time-intensive, and in many cases requires outsourcing specialized surveying work, creating a significant cost burden. Methods that use tape measures, leveling staffs, and spirit levels to measure dimensions point by point and check errors against design values are limited in measurement locations and prone to oversights. If defects are pointed out later and rework is required, this leads to additional expenses. Also, when staff must travel to the site to attend inspections by the client (owner), travel expenses and per-diems are incurred.

A solution that has attracted attention in recent years is using 3D point cloud data for as-built management. A point cloud is a collection of numerous point (coordinate) data acquired by scanning a site with laser or photogrammetry, and can be thought of as a “high-accuracy 3D record that copies the entire site.” Using this digital measurement technology, you can non-contact measure wide areas of as-built conditions in a short time, enabling efficiency and labor savings that were difficult with conventional methods. The Ministry of Land, Infrastructure, Transport and Tourism is also promoting the introduction of 3D surveying technologies as part of the *i-Construction* initiative, and the use of point clouds is spreading across the civil engineering industry from large to small firms.

Benefits of Completing As-Built Management In-House

The biggest feature of as-built management using point cloud data is that surveying and inspection processes, which were often outsourced, can be completed in-house. Traditionally, many cases involved requesting a surveying company for each as-built measurement and paying large outsourcing fees. However, if a company acquires measurement equipment and has staff perform point cloud measurements, it becomes possible to bring surveying outsourcing costs close to zero. You can avoid the hassle of coordinating with external vendors’ schedules and reduce waiting days for report completion. Conducting as-built management in-house enables rapid data acquisition and flexible response, reducing indirect costs caused by unnecessary standby times.

The benefits of in-house completion go beyond cost. If your own staff can handle point cloud measurement, you can perform surveys immediately at the necessary timing according to site progress. For example, for moments such as before and after concrete placement or before and after backfilling—timings that might be missed if outsourced—you can flexibly conduct 3D scans in-house. This helps prevent rework and avoid quality troubles, ultimately suppressing the cost of rework. In addition, if you retain the data in-house, it can be freely used internally, smoothing information sharing with design and construction management departments and contributing to improved productivity across the organization.

Specific Costs Reduced by Point Cloud As-Built Management

Introducing point cloud technology can produce various cost-saving effects on construction sites. Below is a summary of the main costs that can be reduced when point clouds are used for as-built management.

• Reduction of surveying outsourcing fees: As noted above, performing point cloud measurements in-house can dramatically reduce fees paid to surveying companies. There have been sites where each as-built measurement would traditionally incur outsourcing fees on the order of hundreds of thousands of yen, but if equipment and personnel are secured in-house, those per-measurement payments become unnecessary. For contractors handling multiple sites annually, the cumulative savings from reduced outsourcing fees can be very large.

• Reduction of travel and per-diem expenses: By sharing point cloud data in the cloud, clients and supervisors can perform remote attendance inspections from the office. This reduces the travel expenses and per-diems that had previously been incurred by stakeholders gathering on-site for inspections. In trials of large-scale infrastructure projects, there have been reports that as-built confirmation using point clouds plus 3D design data allowed simplification of on-site attendance by supervisory staff. As guidelines for remote on-site inspections are further developed, travel and accommodation costs can be reduced even more.

• Streamlining of inspection document creation: Once you have 3D point clouds, you can measure any location on the data repeatedly later. In other words, there is no worry about “forgotten measurements,” and multiple inspection documents can be created from a single measurement dataset. For example, as-built drawings, cross-sections, and photo logs can be automatically generated or simplified within point cloud software, greatly reducing the time previously spent on manual drafting and organization. In one demonstration experiment, point cloud use reduced the burden of creating as-built drawings and photo logs, cutting the work time related to as-built inspection by more than 30% compared to conventional methods. For site engineers who were overwhelmed with document preparation and data organization, this represents a major personnel cost saving.

• Reduction of additional investigations and rework: Because point cloud data records the site shape with high density, it can cover almost all required information. Traditionally, inspections sometimes uncovered “areas that differ from the drawings,” necessitating repeated measurements and causing rework. But if the entire site is digitized with a point cloud, omissions are less likely and it is easy to review the data later to supplement missing information. Fewer re-surveys and additional investigations mean savings in labor, equipment costs, and time. Early detection and correction of defects also prevent escalation into major construction errors, helping avoid waste of materials and construction costs due to rework.

• Efficiency from data reuse: Once acquired, point cloud data can be reused for various purposes beyond as-built management. For example, using the same data for earthwork volume calculations, as-built verification, preparation of as-built drawings, and maintenance documentation reduces the need for additional field surveys. Whereas separate surveys or photo shoots were previously required for each purpose, point clouds allow the image of “one measurement covering multiple tasks.” Broadening the uses of data raises overall work efficiency and, as a result, contributes to reduced personnel costs and project-wide cost compression.

Initial Investment in 3D Measurement Technology and Cost Effectiveness

A major concern when introducing point cloud as-built management is the initial investment cost for equipment and software. High-performance 3D laser scanners and drone LiDAR systems can cost several million to tens of millions of yen, which may feel like a high barrier for small and medium-sized enterprises. However, in recent years there have been increasing examples of using national subsidy programs to introduce such advanced equipment. For example, by utilizing manufacturing subsidies or labor-saving investment subsidies, it is sometimes possible to cover about half of the equipment purchase cost with grants, greatly reducing the company’s out-of-pocket expense. Simulation results have reported that when subsidies are used, the investment recovery period (ROI) can be shortened by about half.

Furthermore, recently low-cost measurement solutions have emerged that make it possible to introduce point clouds with much lower initial investment. Examples include simple 3D measurement using the LiDAR scanners built into iPhones and iPads, inexpensive handheld 3D scanners, and photogrammetry via smartphone apps. While these tools are somewhat less accurate than expensive professional equipment, they are practically usable for as-built management and quantity estimation if the error range is on the order of a few centimeters (a few in). Many companies are adopting a phased strategy of trying inexpensive equipment first to experience the benefits, then gradually moving to full-scale introduction. Once know-how is accumulated after initial introduction, the value of reduced surveying outsourcing fees and improved operational efficiency becomes clear, and initial investments can be recovered over the mid to long term. There are real cases of dramatic efficiency gains such as “work time reduced to 60% of previous levels after point cloud introduction” and “drawing production that used to take a week reduced to one day,” directly cutting personnel expenses and equipment rental costs.

National DX Promotion Policies and Responses to Remote Inspections

The Ministry of Land, Infrastructure, Transport and Tourism is strongly promoting DX (digital transformation) in the construction industry. Specifically, ICT earthworks and i-Construction are making the use of 3D data a principle and promoting digitalization of construction management. ICT-utilized works are already becoming standard for ministry-managed projects, and submission of point cloud data and electronic deliverables for as-built management is expected to become common. Since the 2020s, there has also been a focus on remote technologies, and guidelines for remote on-site confirmation (online site verification) are being developed to enable on-site inspections to be conducted online. Point cloud data fits perfectly with this trend and is attracting attention as a means of understanding detailed site conditions from remote locations.

Preparing a system that can respond to these national policies will contribute to smoother cooperation with clients and improved competitiveness. Some local governments are beginning to prepare environments that accept point cloud data from the client side, and if you can submit as-built inspection documents as electronic data, printing and postage costs for paper drawings will be unnecessary. Complete online inspection may become realistic in the future, and approvals could be confirmed without personnel gathering on site. This would eliminate travel time and scheduling losses, allowing both contractors and clients to achieve efficiency and cost savings.

Also notable among the benefits of DX promotion policies is the availability of various subsidies and support measures. In addition to the subsidies mentioned earlier, there are municipality-specific ICT introduction subsidies, and the ministry provides technical training and case study collections, expanding support that makes it easier for small and medium enterprises to introduce digital technologies. The government’s policy encourages starting with technologies that are easy to adopt, and it recommends trying point cloud utilization with accessible devices such as smartphones and drones. By leveraging national support measures effectively while responding to DX, you can introduce advanced technology with low risk and low cost, improving productivity and enabling business expansion.

Start Point Cloud As-Built Management with a Smartphone × Small GNSS — Using LRTK

You might wonder whether in-house point cloud measurement requires expensive equipment and advanced skills. However, recently solutions have emerged that allow easy acquisition of high-accuracy point clouds simply by combining a smartphone with a small GNSS receiver. A representative example is LRTK. LRTK is a palm-sized RTK-GNSS receiver that can be attached to a smartphone; by attaching a small antenna to an iPhone, for instance, you can turn the phone into a surveying instrument capable of centimeter-level positioning (cm level accuracy (half-inch accuracy)). Despite weighing only a few hundred grams, this compact device obtains precise position information that a standalone smartphone cannot provide, and the acquired point cloud data can be immediately assigned absolute coordinates of latitude, longitude, and elevation. This eliminates the need for post-processing to align with control points, making it easy to use even on sites with limited specialist knowledge.

By using a smartphone’s built-in LiDAR or camera for 3D scanning and enhancing the positional information with LRTK, you can now perform as-built measurements that once required specialized equipment with a single smartphone. Some dedicated apps automate the entire workflow from point cloud scanning to volume calculation and drawing generation, so you won’t be troubled by complex software operations. Simple UIs that even novice engineers can intuitively use are available, so with basic training anyone can learn in a short time. It’s also easy to scan the surrounding area during gaps in site work, allowing you to start with measurements of small structures and gradually build skills.

Most importantly, the smartphone × GNSS approach offers excellent cost performance. Since you simply add an aftermarket device to a smartphone you may already own, initial investment is minimal. Companies that cannot afford an expensive laser scanner can more easily introduce a low-cost solution like LRTK, making the cost-effectiveness high. The image of “point clouds = expensive and difficult” is becoming outdated, and now small and medium enterprises can adopt them affordably. There are even reported cases where a smartphone + LRTK scanned the underside of a bridge girder and accurately recorded as-built conditions in tight spaces beneath the bridge. Using these easy-to-use, high-accuracy tools, sites without specialist survey staff can still implement point cloud as-built management.

Conclusion: The Future of Cost Reduction Realized by Labor Savings and High Accuracy

As-built management using point cloud data simultaneously achieves labor savings and higher accuracy, making a major contribution to direct and indirect cost reductions. In addition to immediate cost-cutting effects such as reduced surveying outsourcing fees and travel expenses, it also delivers operational efficiency gains through shorter work times and improved quality, dramatically increasing site productivity. In an industry facing labor shortages and work-style reforms, point cloud as-built management will become the new norm for efficiently delivering high-quality construction with limited personnel.

The barriers to introduction are falling year by year, and you can start with simple methods using smartphones or drones to verify results and then scale up gradually. Fortunately, solutions such as LRTK that combine “ease of use” and “high accuracy” have appeared. By beginning with accessible 3D point cloud utilization, you can experience the great benefit of in-house as-built management without relying on outsourcing. I hope the introduction of point cloud as-built management will be your company’s first step toward cost reduction and DX promotion, strengthening competitiveness in the future. Now, harness the latest technology and carve out the future of construction sites!