Visualizing Drawings in AR Construction: Dramatically Improving On-Site Understanding

Table of Contents

• AR technology spreading in the construction industry

• Challenges that drawings alone cannot convey

• Benefits of visualizing drawings with AR

• Use cases of AR on construction sites

• Points for AR introduction and challenges for higher accuracy

• Simple surveying with LRTK: high-precision AR anyone can do

• FAQ

AR technology spreading in the construction industry

AR (augmented reality) is a technology that overlays digital information on live images of the real world. Through smartphones or tablets, it projects 3D models, text, and other elements onto the scene in front of you, blending virtual objects with the real world. Originally highlighted in the entertainment field, AR has recently been rapidly adopted in the construction industry. For example, driven by the Ministry of Land, Infrastructure, Transport and Tourism’s promotion of "i-Construction" and the trend toward DX (digital transformation) on sites, AR use is spreading not only among major general contractors but also to small and medium construction companies, clients (owners), and local governments.

The construction industry’s interest in AR stems from common challenges such as labor shortages, the aging of skilled technicians, and strengthened safety measures. AR technology is expected to deliver various effects, including improved on-site productivity, more efficient skill transfer, and enhanced safety. In practice, there are increasing examples of using AR apps that display drawings or BIM models on site, reducing construction errors and smoothing communication. As these success stories become better known, AR usage at construction sites—summed up by the keyword "AR construction"—is likely to expand further.

This article broadly explains AR technology basics, its usage in the construction industry, concrete benefits and case studies, and key points for implementation. At the end of the article, we also introduce a new technology: a high-precision simple surveying solution using LRTK.

Challenges that drawings alone cannot convey

Traditionally, construction sites have used paper drawings or CAD drawings to confirm施工内容. However, there is a problem that two-dimensional drawings alone make it difficult to grasp the spatial image of the finished product. Experienced personnel can imagine three-dimensional forms from drawings, but it is not easy for less experienced engineers or clients and neighbors who do not usually deal with drawings to correctly visualize the finished form from a drawing. As a result, misunderstandings and communication losses can occur, leading to rework and mistakes on site.

Another challenge of traditional methods is the time lag when survey values measured on site are taken back to the office and compared with drawings before problems are discovered. For example, it has been the case that insufficient thickness of concrete was discovered after pouring, or positional shifts of buried pipes were noticed only after backfilling. If problem discovery is delayed, extra cost and effort are required to redo the work. Relying on paper drawings for verification makes it difficult to immediately grasp the situation on site, leaving issues in both efficiency and quality.

Moreover, inefficiencies have been pointed out in the surveying and as-built management tasks themselves. Traditionally, expensive surveying instruments such as total stations and levels were used, and a two-person team was required to measure large areas bit by bit. Such work dependent on skilled personnel is becoming difficult to sustain amid worsening labor shortages. To improve on-site understanding, reduce errors, and streamline work, a new method that can visualize drawing information more intuitively on site is needed.

Benefits of visualizing drawings with AR

Overlaying drawing information on site with AR offers many advantages not available in conventional methods. Here are some major benefits.

• Intuitive spatial understanding: Three-dimensional structures that are hard to grasp from lines and numbers on a drawing can appear on site as full-scale 3D models with AR. For example, displaying a life-size model of a completed building on an empty lot allows on-site, three-dimensional confirmation so that the design intent can be understood intuitively. There is no need to mentally convert drawings into 3D; information can be shared in a way that is easy to understand for everyone.

• Smoother communication: AR enables all stakeholders to share the same image of the finished product on the spot, reducing discrepancies in understanding. When explaining to clients or nearby residents, showing visuals overlaid on the actual landscape increases persuasiveness and facilitates consensus building. Parts that were difficult to convey with words or drawings alone can be understood visually—truly a picture is worth a thousand words.

• Reduction of construction errors and rework: If you can confirm on site via AR whether construction is being carried out according to the drawings, deviations or shortages can be detected early on the spot. Dimensional differences, interferences, and omissions that would have gone unnoticed until later can be detected and corrected during construction, preventing significant rework. This reduces the risk of quality defects and shortens schedules.

• Improved work efficiency: AR eliminates the need to repeatedly compare drawings or take survey point data back for verification. By simply pointing a camera on site, you can compare the design model with the current condition, enabling real-time as-built checks and greatly simplifying tasks such as taking photos for reports and measuring. Because AR is intuitive to use even for non-experts, it contributes to overall team productivity.

• Enhanced safety: AR is useful not only for construction planning but also for safety management. You can visualize hazardous areas or no-entry zones in AR to warn workers, or display the correct installation positions for safety equipment during high-elevation work. Visual alerts improve the effectiveness of safety training and help prevent industrial accidents.

Use cases of AR on construction sites

In what scenes does AR prove effective on actual construction sites? Here are some concrete use cases of drawing visualization with AR.

• Pre-construction planning simulation: Before work begins, display the 3D model from the design stage over the site. If you display the planned building or structure on an empty site with AR, you can intuitively check how it integrates with the surroundings and its impact on the landscape. It is more persuasive than models or perspective drawings and contributes greatly to achieving consensus with clients and local residents.

• As-built verification during construction: As work progresses, verify on the spot with AR whether constructed parts match the design. For example, you can verify through the camera whether the positions and heights of columns and walls are not shifted relative to the drawings, or whether pavement thickness is as specified. This allows immediate correction before the discrepancies are pointed out later, improving quality control accuracy.

• Visualization of buried objects and interference checks: Pipes and cables buried underground become invisible after construction. By using AR, you can display pipe routes on the ground before burial to confirm appropriate depth and paths. You can also display existing buried object data in AR to identify interference risks in advance so other equipment is not accidentally damaged during excavation.

• Heavy equipment operation support: AR can be used to support construction machinery operation. For example, at an excavation site, if the design excavation surface is shown on the ground in AR, the operator can scoop soil to the correct depth and slope. AR can also display guides for final heights in paving work. Visual guidelines enable even non-experts to perform high-precision work, improving construction efficiency.

As shown above, AR creates new value in many situations from the design stage through construction and inspection. It helps identify problems that were easily overlooked with conventional methods and serves as a practical means to share understanding among stakeholders; AR has already begun to produce tangible effects on site.

Points for AR introduction and challenges for higher accuracy

To visualize drawings on site with AR, there are several points and challenges to overcome. First you need devices and apps. Modern iPhones, Android smartphones, and tablets are equipped with high-performance cameras and sensors, and with dedicated AR apps you can display 3D models of construction drawings. Especially on the latest models, built-in LiDAR scanners can instantly capture surrounding terrain and structures as point cloud data, allowing AR models to be naturally placed on the real ground and enabling occlusion where virtual objects are hidden behind real objects.

Also, AR platforms such as Apple’s ARKit and Google’s ARCore provide VIO (Visual Inertial Odometry) technology that combines camera images and device sensor information to track the device’s position and orientation in real time. This mechanism makes it possible to keep virtual objects anchored in place even when the user walks around, enabling stable AR display that fixes models in physical space.

Next, digital data such as 3D models is important. To display with AR, the source design data must be modeled in three dimensions. BIM/CIM models and other 3D design data are beginning to be used in architecture and civil engineering, and if these are available, importing them into AR is relatively smooth. Even without BIM data, you can create simple 3D models from 2D drawings or obtain point clouds by laser scanning the site to prepare data usable for AR.

A major point in AR adoption is the challenge of positioning accuracy. In confined spaces like indoors, you can align models using floor markers or wall feature points. However, accurately overlaying 3D models on large outdoor construction sites requires the device’s position to correspond to real-world coordinates with high accuracy. Typical smartphone-built-in GPS can have errors of several meters (several ft), causing the model and actual structures to be misaligned. Because normal smartphone AR calculates positions relatively within the device, accumulated drift can cause virtual models to gradually deviate from reality when moving long distances.

To solve this positioning accuracy issue, a method called "absolute coordinate AR" has attracted attention. Absolute coordinate AR performs AR display based on absolute coordinates (latitude and longitude) obtained from satellite positioning systems such as GPS and Japan’s quasi-zenith satellite Michibiki. This makes it possible to overlay virtual models in their true positions even on large sites. However, high-precision positioning requires special GNSS receivers using RTK positioning (real-time kinematic). RTK positioning can pinpoint positions with errors down to a few centimeters (a few inches), but until recently it required expensive equipment costing millions of yen, posing a high hurdle for small and medium contractors. Recently, compact high-precision GNSS antennas that attach to smartphones have appeared, and leveraging such new technologies has made it possible to overcome this challenge.

Simple surveying with LRTK: high-precision AR anyone can do

One accessible solution to achieve the high-precision positioning described above is LRTK. LRTK consists of a compact RTK-GNSS receiver that can be attached to a smartphone and a dedicated app, transforming your smartphone into a surveying instrument with centimeter-class accuracy (half-inch accuracy). This innovative technology lets you handle accurate position information on a smartphone that previously could only be obtained with specialized surveying instruments.

Using LRTK, you can perform high-accuracy alignment between design models and the real world even on large construction sites. For example, when displaying the planned model through a smartphone before construction, LRTK lets you place the model based on actual latitude and longitude so it can be overlaid on site with no error of even a few centimeters (a few inches). In as-built management during construction, you can instantly compare measured point cloud data or as-built models with the design data and display advanced checks such as heat maps showing deviations on site. Inspection tasks that used to take time from surveying to drawing can now be completed on the spot in real time by combining AR and LRTK.

LRTK is also easy to use because of device miniaturization and simplification, making it accessible to anyone on site. It is attached to a smartphone for easy portability and requires little complex setup. Position correction is performed through intuitive app operations, so even those without surveying expertise can master it quickly. Because you do not need to procure expensive dedicated equipment, it is also cost-effective. LRTK is truly a solution that brings cutting-edge technology to the field in a form everyone can use.

By combining AR and LRTK in this way, you can dramatically improve on-site understanding and work efficiency simultaneously. Real-time acquisition of centimeter-precision positioning data and intuitive AR visualization enable immediate quality checks and corrections on site. As a result, rework and additional construction are reduced, guiding the resolution of the difficult challenge of balancing quality assurance and efficiency on construction sites.

※ For detailed product information and case studies of LRTK, please also visit the official site ([LRTK official site](https://www.lrtk.lefixea.com)).

FAQ

Q: What equipment is required to use AR on site? A: Basically, a mobile device such as a smartphone or tablet is enough to experience AR. Newer devices have high-performance cameras and sensors, enabling more stable AR display. In addition, you need 3D data created from construction drawings and an AR app to display it. For wide-area, high-precision use, a high-precision GNSS device that can be attached to a smartphone—such as LRTK—is ideal.

Q: Are specialized skills or training required for introduction? A: Operation itself is intuitive and no special skills are required. AR apps display models simply by following on-screen instructions and pointing your smartphone, and LRTK’s dedicated app automatically performs positioning correction, so first-time users can get accustomed in a short time. However, some CAD or BIM knowledge is helpful when preparing 3D data for AR. If no one in your organization has that expertise, start with simple models and gradually improve accuracy.

Q: Can you achieve accurate alignment with just a smartphone? A: In confined spaces such as indoors, smartphone-only AR can be sufficient. However, on large outdoor sites, smartphone-built-in GPS can have errors of several meters (several ft), making it inadequate for precise alignment. RTK-GNSS technology such as LRTK is useful here. With LRTK, you can correct device position to centimeter-level accuracy (half-inch accuracy), enabling AR display with design-level precision even on large sites.

Q: Isn’t AR implementation costly? Can small and medium businesses adopt it? A: It is true that in the past, expensive investments in AR glasses and dedicated equipment were necessary. But today, smartphone-based AR is mainstream, greatly lowering initial cost barriers. Devices like LRTK have been miniaturized and cost-reduced to include only necessary functions, making them affordable for small and medium businesses. Considering cost reductions from fewer construction errors and improved work efficiency, you can expect a sufficient return on investment.

Q: Will AR completely replace traditional drawings and surveying? A: AR is a complementary tool to deepen on-site understanding and does not make traditional drawings and surveying entirely unnecessary. Accurate construction still requires design drawings and official surveying data. However, using AR alongside these tools makes it easier to share design intent on site and contributes greatly to error prevention and inspection efficiency. AR will increasingly play an important role as a means to supplement information that paper drawings alone cannot convey.

Q: Can AR be used on any site? A: In principle, AR can be used at various sites both outdoors and indoors. However, to fully realize AR’s benefits, digitized design data and an appropriate environment are desirable. If only old drawings exist, you can measure the site and digitize the data for AR display. In GPS-denied indoor environments, methods such as LiDAR scanning or marker-based alignment are needed. Choosing the appropriate AR approach according to the type and scale of the site is key.