What is 3D Construction? The New Trend in On-site DX Realized by LRTK

Introduction

In the construction and civil engineering industries, digital transformation (DX) aimed at improving productivity and efficiency is progressing rapidly. There are also challenges such as a shortage and aging of skilled surveying technicians, making labor-saving through digital technology a necessity. Among these trends, "3D construction," which acquires and utilizes on-site information in three dimensions, is attracting attention as the core of on-site DX (digital construction). Precise surveying that once required specialist surveyors and expensive equipment is becoming accessible to anyone thanks to technological innovation. In this article, we explain what 3D construction is and explore how the positioning and measurement technology that is becoming the new norm, LRTK, enables anyone to practice on-site DX.

Benefits Brought by 3D Construction

In recent years, opportunities to handle survey and design data in three dimensions on construction sites have increased dramatically. By acquiring and using terrain and structures as point cloud data or 3D models, the gap between design and construction can be visualized, and verification of as-built conditions can be made more efficient. The Ministry of Land, Infrastructure, Transport and Tourism’s promoted ICT construction (so-called *i-Construction*) also treats the use of 3D survey data as a key pillar. For example, photogrammetry by drones and detailed point clouds of existing terrain acquired by terrestrial laser scanners are becoming common for earthwork volume calculations and construction planning. Introducing 3D data allows intuitive understanding of site conditions that could not be seen from drawings or numbers alone, making it easier to share understanding among stakeholders. This leads to improved quality and safety as well as shortened construction schedules. Furthermore, 3D survey data is beginning to be used in advanced technologies such as machine guidance (MG) and machine control (MC) for heavy machinery, creating a flow in which the survey-obtained existing data and design models are directly reflected in construction. 3D construction is transforming the entire construction production process in this way.

Challenges in Traditional Construction Management

While the value of 3D surveying and digital construction has become recognized, traditional methods had several hurdles. High-precision surveying required specialized equipment such as total stations or high-end GPS surveying instruments, and work was typically done by a two-person team including a surveyor. Detailed point cloud measurement by laser scanners and photogrammetry by drone carried high equipment costs, and required advanced skills and dedicated software to operate. For these reasons, small-scale sites or sites with labor shortages often find it difficult to fully adopt these technologies. In particular, as surveying skill workers age and younger workers are scarce, reliance on personnel-dependent surveying and construction management has limits.

In addition, using acquired 3D data on-site required expertise such as coordinate transformation and data processing, making real-time information sharing and utilization difficult. Even if point cloud data were obtained, it often had to be processed on high-performance PCs to be effectively used, and in practice sites would revert to checking with 2D drawings. In other words, maximizing the benefits of 3D surveying and 3D construction traditionally required considerable investment and expertise.

What is LRTK? A New Technology Supporting On-site DX

Against this backdrop, LRTK has emerged as a solution that overturns conventional assumptions. LRTK is a next-generation positioning and measurement system that makes RTK-GNSS (real-time kinematic positioning) technology easily usable on smartphones. Simply attaching a dedicated ultra-compact GNSS receiver to a smartphone or tablet can improve a smartphone’s positioning accuracy, which normally has errors of several meters, dramatically to centimeter-level (half-inch accuracy). The RTK method receives satellite signals simultaneously at a base station installed at a known point and at a rover (the point to be measured), canceling common error factors to correct the rover’s position to centimeter-level (half-inch accuracy). Performing this in real time enables instant high-precision positioning of arbitrary points. Recently, network RTK using the Geospatial Information Authority of Japan’s electronic reference point network and centimeter-class augmentation signals (CLAS) from Japan’s satellite system “Michibiki” have become widespread, making high-precision positioning possible without dedicated base stations. LRTK leverages these systems and has succeeded in completing precise positioning and 3D measurement that previously required specialized surveying equipment with a single smartphone.

LRTK consists of a small device attached to a smartphone (weighing only about 165 g) and a dedicated app, and it is palm-sized and easy to carry. Since the battery and antenna are integrated, you can take it out of your pocket on site and start surveying immediately. It is designed to be usable by anyone with minimal instruction, allowing a single person to complete on-site surveying, measurement, and verification tasks. Heavy tripods and complicated equipment that were previously necessary are no longer needed; it truly realizes an “all-purpose surveying instrument” on a smartphone.

On-site Problems LRTK Can Solve

Let’s organize how the construction site issues described above can be resolved by introducing LRTK.

• Resolving labor shortages: With LRTK, one smartphone and a small terminal allow one person to handle surveying through as-built verification, enabling sites lacking specialist survey technicians to respond. Its intuitive operation means inexperienced juniors can handle it after short training, contributing to easing personnel shortages.

• Improving surveying accuracy: Positioning errors that were several meters with conventional GPS are reduced to a few centimeters by LRTK’s RTK positioning. This enables highly accurate setting out for stake driving and installation of structures, and as-built measurement can detect minute deviations. Reduced surveying errors directly lead to improved construction quality and fewer mistakes.

• Cost reduction: Costs for procuring specialized equipment or outsourcing to surveying contractors can be reduced. Since only a smartphone and the LRTK device are required, initial investment can be significantly lowered and maintenance costs are minimal. Preventing rework and additional construction due to construction mistakes also contributes to overall cost savings.

• Prevention of rework and redo: With LRTK, 3D measurement and verification can be performed at any time during construction, allowing deviations or shortages to be detected on the spot. Using AR to overlay design models prevents situations where one notices errors only after completion and has to correct them. Because construction can proceed while staying close to the design, unnecessary rework decreases, enabling both shortened schedules and quality assurance.

Main Functions of LRTK and Use Cases

LRTK is equipped with various functions that make on-site DX a reality. Here are the main functions and their concrete use cases.

• High-precision point cloud scanning: Utilizing the smartphone’s built-in LiDAR sensor or camera, you can quickly scan surrounding terrain and structures to obtain high-density 3D point cloud data. The acquired point clouds are assigned global coordinates (latitude, longitude, elevation), so each point is tied to real-world coordinates. Usage is simple: just walk while holding the smartphone. You can scan large areas in a few minutes; for example, you can record the shape of a large slope in about 1 minute. Scanned point clouds can be checked immediately on-site and used for distance, area, and volume measurements. In disaster response scenarios, point cloud scanning helps quickly assess the volume of collapsed slopes or washed-away sediment. By performing remote 3D scans, you can safely record conditions in hazardous areas where people cannot enter. In civil engineering, scans are used to calculate earthwork volume by comparing pre- and post-excavation terrain and to preserve completed terrain as digital records, among other applications.

• 3D model display with AR: LRTK’s AR (augmented reality) feature projects 3D models and drawing data created at the design stage into real space and displays them at actual scale on the smartphone screen. Because models are placed based on high-precision positioning information, no manual alignment is needed and AR displays without offsets are possible. Simply load design data (for example, BIM/CIM models or 3D design drawings) into the LRTK app and display them on the screen to overlay with the site view. This allows direct comparison of the design model and the actual site in structure construction, enabling on-the-spot checks of formworks and rebar placement against the drawings. In road construction, AR can display the finished image to confirm whether pavement thickness and curb lines match the plan. In residential construction, on detached-house sites, projecting a 3D model of the finished building or exterior onto the lot helps share the completion image with clients during meetings. Furthermore, if underground utilities (such as buried pipes) have been scanned and recorded in advance with LRTK, their underground locations can be visualized with AR during subsequent excavation works, reducing the risk of accidental damage to pipes.

• Coordinate navigation (stake setting guidance): LRTK includes a function that navigates the user to any target coordinate point. For pre-set coordinate values, arrows and distance information are displayed on the smartphone screen, and following these prompts leads you to the target point. This makes stake setting and locating reference points easy even without specialized surveying knowledge. For example, when driving stakes for the foundation positions indicated on plans, the coordinate navigation can mark the exact positions with centimeter accuracy. This function is also powerful when searching for boundary markers or existing survey stakes hidden by vegetation or snow. A single person with a smartphone can reach target points without multiple people operating surveying equipment, making it easy to work in confined or vertically varied sites. Coordinate navigation is useful not only for as-built inspections but also as a guide for periodic inspections and maintenance tasks.

• As-built management (detecting deviations from design): By overlaying point cloud data acquired with LRTK and design data, as-built management can be streamlined. You can intuitively verify with color-coded displays whether the current shape matches the design, and quantify quality during construction. For example, comparing a point cloud uploaded to the LRTK cloud with the design surface data displays areas matching the design in green, areas exceeding the design in red, and areas below the design in blue in a heat map. This instantly shows where fill or cut is lacking or excessive, allowing immediate identification of areas requiring additional work or trimming. The difference in earthwork volume between the current condition and the design is also automatically calculated, enabling on-site judgments such as "how many cubic meters of soil need to be transported" or "how much must be cut to reach the design surface." For slope works or revetment works, which require measurements according to as-built management guidelines, point clouds scanned with LRTK can produce required cross-sections and volume calculations, aiding in preparation of inspection documents. As-built verification, which previously depended on craftsmen’s intuition and manual work, can now be performed objectively and swiftly based on data, bringing significant benefits in both quality assurance and inspection responsiveness.

• Cloud integration and data sharing: Coordinate data, point clouds, photos, and other data obtained with LRTK can be uploaded to the cloud on-site and reviewed and utilized immediately from the office or remote locations. Using the dedicated cloud service, data can be managed and 2D drawings or 3D point clouds can be viewed in a web browser, with distance, area, and volume measurements possible. Without installing expensive desktop software, anyone with an internet connection can handle on-site 3D data. By issuing shared links on the cloud, data can be easily shared with subcontractors or clients who do not hold licenses. Recipients do not need high-performance PCs or dedicated viewers; they can open the shared link to view 3D models and point clouds. This allows stakeholders to grasp construction progress and as-built conditions without visiting the site, facilitating smoother communication. For example, a remote site supervisor or designer can conduct meetings while viewing point cloud models on the cloud and issue additional instructions the same day. In disaster recovery, quickly sharing scanned data of affected sites via the cloud enables municipal headquarters and experts to assess damage from their offices and promptly consider response strategies.

Work Efficiency Improvements and DX Effects from LRTK Adoption

As described above, using LRTK dramatically streamlines on-site surveying and construction management. As-built surveying and earthwork calculations that used to take days can be completed on the spot and shared immediately, accelerating decision-making. There is less need to arrange specialized surveying contractors or to stop heavy machinery for surveying, improving construction productivity. With tasks doable by one person, labor costs and personnel coordination are reduced, enabling efficient operations like one person managing multiple sites.

Data-driven construction offers higher reproducibility than analog work reliant on "intuition and experience," making it easier to ensure consistent quality regardless of who performs the work. This is a major DX benefit, reducing dependence on individual skills and raising the overall baseline of the organization. Accumulating construction records in the cloud also forms digital assets useful for analyzing past cases and planning future projects. For instance, storing point cloud data makes it easy to compare conditions during future maintenance, benefiting the post-construction lifecycle.

Above all, advancing on-site DX helps address long-standing issues in the construction industry regarding safety and working conditions. Remote surveying of dangerous slopes and reducing physically demanding tasks such as installing batter boards both lighten worker burdens and enhance safety. Paperless workflows and data sharing reduce time spent on report preparation and communication errors, making construction management itself smarter. Thus, LRTK adoption not only improves operational efficiency but also contributes to work-style reform and business model transformation in the field.

Conclusion

We have reviewed "3D construction" and LRTK, which supports its realization. How did you find it? Three-dimensional technologies that were once limited to large-scale sites and specialists have become much more accessible with the advent of LRTK. The ease of simple, high-precision surveying with a single smartphone is a reassuring ally for sites embarking on digital construction for the first time. Feedback from sites that have actually introduced LRTK includes comments such as "even newcomers could survey immediately" and "being able to check as-built conditions routinely has increased peace of mind," and it has been well received as an entry point to on-site DX.

LRTK’s small size, light weight, and ease of use allow it to be integrated into existing construction workflows with minimal disruption, lowering the barrier to on-site adoption. No special equipment preparation or complicated setup is required; measurements and recordings can be taken quickly when needed. This convenience and immediacy not only directly improve productivity but also reduce resistance among site staff toward DX. If your company is considering DX to resolve labor shortages, improve operational efficiency, or enhance quality in your projects, why not try [LRTK](https://www.lrtk.lefixea.com/lrtk-phone) on-site once? You will likely experience construction management progressing with unprecedented speed and accuracy. LRTK is poised to become the new standard in the construction industry as an on-site DX tool anyone can use. Please verify its effects on your site.