BIM×AR is Changing the Field! 3D Construction Management Achievable with Just One Smartphone

Introduction

On construction and civil engineering sites, there is often more information than can be conveyed by paper drawings or photos alone, which can lead to miscommunication and construction errors. One approach gaining attention in recent years to address these challenges is "3D construction management," which combines BIM (Building Information Modeling) and AR (augmented reality). BIM is a method of linking all kinds of information to detailed three-dimensional models of buildings and infrastructure for unified management, and it is expected to be a key driver of digitalization across construction projects—from design through construction and maintenance. AR technology, on the other hand, overlays CG models or textual information on real-world images seen through a camera on a smartphone or similar device, making it a tool that truly bridges the field and the digital world.

Imagine pointing a smartphone camera at a construction site and seeing the BIM model of a structure that hasn’t been built yet appear at full scale in the actual scene. Because you can confirm the completed image that previously could only be seen on drawings or a computer screen "on-site" and "at full scale", you can intuitively grasp the space and facilitate smoother consensus building. It can be used widely for on-site checks, verification of as-built conditions, and even future maintenance. Decisions that used to rely on veteran intuition and experience can be explained with the persuasive power of overlaying a digital model on the real scene—truly a case of "seeing is believing." In particular, smartphone performance has improved dramatically in recent years; modern devices like the iPhone now include LiDAR sensors capable of 3D scanning, enabling high-performance AR displays with ease. This article explains in detail the benefits and use cases of 3D construction management using BIM and AR, and the technologies that make high-precision construction management possible with a single smartphone.

What is BIM? The growing use of 3D data in construction

BIM (Building Information Modeling) uses three-dimensional digital models that represent the shapes and attributes of buildings and civil structures to utilize information across the entire construction lifecycle—from planning and design through construction and maintenance. By consolidating information that used to be managed separately (design drawings, specifications, etc.) into a BIM model, projects can proceed while all stakeholders always share the latest data. For example, a BIM model can link various information such as component dimensions and materials, schedules and costs, and maintenance history, functioning as a "digital building itself" rather than just a 3D drawing.

Adoption of BIM is accelerating in Japan as well, with the Ministry of Land, Infrastructure, Transport and Tourism promoting the use of BIM/CIM, especially in large projects. From fiscal 2023 (Reiwa 5), BIM/CIM began to be applied in principle to some public works commissioned by the ministry, and from fiscal 2024 onward it is scheduled to be expanded stepwise to local governments and private-sector projects. There is even a goal to make BIM/CIM use mandatory for nearly all public works in the future, marking a major turning point for the construction industry. Consequently, many construction companies have begun introducing BIM software and investing in human resource development, shifting operations from predominantly 2D drawing-based work to workflows that leverage 3D data. The purpose of introducing BIM is not only to enhance design but also to improve productivity and ensure quality during the construction stage. In practice, using BIM models has begun to streamline construction planning and reduce the effort required for as-built verification, demonstrating tangible improvements in on-site operations.

What becomes possible when BIM models are overlaid on the site with AR?

So what exactly can you do when you overlay BIM’s 3D models on real space using AR? Here are the main benefits enabled by this combination.

• Facilitating consensus building: AR allows owners, designers, contractors, and all stakeholders to share the same completed image on-site, reducing misunderstandings and speeding decision-making. Spatial dimensions and finishes that were difficult to grasp from paper drawings become immediately clear when the model is overlaid on the real scene, greatly increasing persuasive power. For example, in road and bridge projects, AR has been used in resident briefings to project the expected finished view on site, helping to smooth consensus with local communities. Because "what kind of structure will be built here" becomes clear to everyone’s eyes, the "seeing is believing" effect helps ease anxiety and opposition.

• Reducing construction errors: Using intuitive AR guidance lets workers verify on the spot whether elements are being installed at the correct positions and heights as specified in the design. For instance, when installing rebar or piping, showing design position guides on a smartphone AR screen enables accurate placement even by non-experts. At sites using AR navigation for positioning pile driving and anchor installations, layout marking work that once took experienced workers half a day has been completed in a much shorter time, and human errors have been dramatically reduced. AR that shows "install here" through the screen acts like a digital site supervisor’s instruction, building confidence. Fewer measurement mistakes or position errors mean fewer rework tasks, shortening schedules and improving construction quality.

• Streamlining inspections and progress management: AR is also powerful for as-built inspections during and after construction. By overlaying the BIM model on completed structures or formed terrain, you can visually grasp discrepancies from the design model. For example, displaying deviations between model and reality as a color distribution (a heat map) in AR makes areas needing additional work immediately obvious. Inspectors can also directly read key dimensions and height information from the model and compare them to the actual object, eliminating the need to spread out drawings for verification. Inspectors can check on the spot while looking at the smartphone screen and, if necessary, take photos with the AR overlay for records—making later explanations in the office much clearer. In progress management, comparing the actual site with planned designs via AR helps detect construction omissions or defective finishes early, and improves the efficiency of report preparation.

• Applications to maintenance and safety measures: BIM×AR can also be applied to post-completion infrastructure maintenance and on-site safety. For example, see-through displays of buried utilities can visualize the positions of water and sewer pipes, cables, and other buried infrastructure under the road from above ground using AR. If you prepare underground utility position data or a BIM model beforehand, simply pointing a smartphone at the site during maintenance will reveal the subterranean pipe routes, allowing you to recognize hazardous areas as if you were seeing through the ground. This helps prevent accidental excavation damage to existing infrastructure and promotes safer work. In routine inspections of bridges and tunnels, past recorded crack locations and repair histories can be overlaid on the actual structure via AR, or inspectors can leave notes of anomalies discovered on-site as 3D records within the BIM model. Because inspections can proceed with the real object and digital records aligned, the risk of oversights decreases and recording accuracy improves.

As shown above, AR technology that allows sharing BIM models in the real world brings multiple effects—faster consensus building, prevention of construction errors, more efficient inspections, and advanced maintenance. These all directly contribute to improved productivity and safety on site, making BIM×AR an innovative approach supporting DX (digital transformation) in the construction industry.

The possibilities of 3D construction management with just one smartphone

A key point in applying BIM×AR on site is that it has become possible to achieve all this with "just a smartphone." Until recently, using 3D models on site required expensive specialized equipment and complex setup. But today, with Apple’s AR platform ARKit and sensors built into smartphones, environments enabling anyone to use AR are becoming widespread. Compared to specialized devices once trialed, such as AR glasses (smart glasses), the fact that site staff can use the smartphones they already carry has great significance.

Take the latest iPhone as an example: its rear-mounted compact LiDAR sensor can laser-scan the surroundings and instantly create a high-precision 3D map. This enables stable markerless AR displays even on outdoor sites that previously required planar markers. However, smartphone-only AR has weaknesses—chiefly the accuracy of model alignment. Built-in GPS on devices has errors on the order of meters, so merely pointing a smartphone at a wide construction site won’t place BIM models at the exact absolute positions required by design. SLAM (simultaneous localization and mapping) by ARKit only captures the device’s relative motion, so while a model may appear "more or less aligned" in the scene, it doesn’t reach the strict precision needed as a construction benchmark.

What solves this issue is the use of high-precision positioning technology called RTK-GNSS. RTK (Real Time Kinematic) uses correction information from a base station to dramatically improve positioning accuracy of GPS and other systems, reducing position errors to a few centimeters. Recently, ultra-compact GNSS receivers that allow easy RTK use with smartphones have started to appear. By attaching a pocket-sized receiver that connects to a smartphone via the Lightning port or Bluetooth and receiving correction data from network correction services or Japan’s Quasi-Zenith Satellite "Michibiki," you can measure current position with precision far beyond what you’d expect from a smartphone.

Combining such high-precision positioning with a smartphone’s AR capability makes it possible to align BIM models exactly to real surveying coordinates. For example, if you preset the site’s survey coordinates (latitude, longitude, elevation) in the BIM model and compare them with the smartphone’s RTK-measured position and orientation, the model will display in the intended position with negligible offset. Previously, a QR-code marker had to be placed on the ground as a reference to align AR models, but high-precision GNSS enables markerless model placement. Since smartphones also have built-in gyros and accelerometers that accurately capture device orientation and tilt, the model remains stably overlaid on the real structure even as the user walks around. In short, the combination of smartphone + LiDAR + AR + RTK has made high-precision outdoor 3D construction management—once difficult—readily accessible.

How LRTK is transforming on-site simple surveying with smartphones

Among smartphone-based BIM×AR solutions, particularly revolutionary is a technology called LRTK. LRTK is attracting attention as a solution that turns a smartphone into an all-purpose surveying instrument by attaching a pocket-sized RTK-GNSS receiver to a smartphone or tablet to enable centimeter-grade positioning. Developed by a Tokyo-based startup, this system allows tasks that previously required skilled surveyors and expensive equipment to be carried out easily by anyone on site with just a smartphone.

For example, for single-point height measurements (leveling) or coordinate checks, simply walking with an LRTK-equipped smartphone lets you sequentially record elevations and positions of points you want to measure. Scenes that used to require a level or total station can now be completed quickly because the smartphone screen displays in real time "this point is at elevation ○m with ±a few centimeters accuracy." Combined with iPhone’s LiDAR scanning functionality, you can perform on-the-spot 3D point cloud measurements of embankments or excavation areas and immediately calculate earthwork volumes automatically. Collected point cloud data can be shared via the cloud, enabling direct use of on-site data for decision-making without returning to the office to create drawings or reports. In practice, advanced workflows have emerged, such as "visually confirming buried road pipes after backfilling using AR." If you scan buried pipes during construction and upload them to the cloud, you can visualize those pipes through your smartphone even after backfilling by standing on the road and viewing them through the device. This allows accurate knowledge of buried objects’ locations for future excavations, enabling safe work planning that doesn’t rely on experience or intuition.

The greatest benefit LRTK brings is on-site responsiveness and labor savings. By simply attaching a receiver to a smartphone and launching an app, the system automatically handles everything from acquiring correction data to positioning, scanning, and data sharing, so it can be used without specialized knowledge. Even amid shortages of veteran surveyors, young staff and non-specialist site workers can perform high-precision measurements and positioning themselves, helping address labor shortages and support skill transfer. Also, because the field and the office can share data in real time, everyone can always access a single source of truth, reducing miscommunication while progressing work. LRTK truly serves as a bridge connecting the field and design offices, the physical and the digital, maximizing the value of BIM×AR solutions.

Conclusion

3D construction management that combines BIM and AR is transforming site landscapes by leveraging the familiar tool of the smartphone. As environments enabling intuitive use of 3D models become commonplace, the barriers between field and design will lower, and decision-making speed and productivity will dramatically improve. With the spread of BIM, digital construction management incorporating advanced technologies like AR and LRTK is expected to develop even further. From an era that relied on paper drawings and veteran intuition, we are moving toward an era in which anyone can measure, verify, and share with just a single smartphone—the fusion of BIM×AR is ushering in a new wave of on-site DX that is beginning in earnest. This wave of digital adoption is likely to become the new standard for construction sites in the not-so-distant future.