CIM Utilization Checklist: Practical LRTK Procedures to Deliver Results Fast

What is CIM? The Key to Digital Transformation in the Construction Industry

CIM (pronounced "sim") stands for Construction Information Modeling/Management, a method that incorporates 3D models and data management into construction projects. It is a concept that applies BIM (Building Information Modeling) from the architectural field to civil engineering and infrastructure, and was proposed by the Ministry of Land, Infrastructure, Transport and Tourism in 2012. Initially aimed at "streamlining construction processes with 3D models," it is now positioned as an initiative to "consistently utilize data across the entire construction lifecycle, from planning and design to construction and maintenance."

By introducing CIM, site information that was difficult to grasp from drawings and documents can be visualized in 3D, and all stakeholders can proceed with discussions while sharing a common model. For example, using 3D models in the design stage makes interference checks between structures and sharing the finished shape easier, reducing the risk of design and construction errors. In the construction phase, everyone from heavy equipment operators to site supervisors and clients can visually confirm the same image of the finished product, reducing communication loss. After completion, if the model is populated with component information and inspection histories, maintenance personnel can quickly retrieve the necessary information. Because of these benefits, CIM is expected to be a trump card for improving operational efficiency and productivity.

In recent years, the government-led digitalization of the construction industry, "i-Construction," has accelerated CIM adoption. From fiscal 2023, direct Ministry projects have begun applying BIM/CIM as a de facto requirement in many works and tasks, and this is expanding to municipal and private projects. To avoid falling behind this trend, all stakeholders—from major contractors to municipalities and small construction firms—are beginning to engage with CIM. Many, however, may be unsure where to start. This article provides a checklist to smoothly introduce CIM and achieve results quickly, explaining steps for each phase. It also covers efficiency points using the new technology *LRTK*, and presents practical procedures easy for beginners to follow.

Preparing for CIM Adoption: Organizing Structure and Developing a Plan

To make CIM successful, preparations and organizational setup are important before introducing specific tools on site. Keep the following points in mind for a smooth start.

• Clarify the purpose and goals of adoption: First, clarify why you are adopting CIM and what outcomes you aim for. For example, establish a common understanding within the company such as "reduce design errors," "shorten construction periods," or "reduce maintenance costs." Clear objectives will enable more accurate planning and tool selection.

• Gain consensus from management and project stakeholders: CIM adoption requires changes to traditional work processes. Obtain understanding and support from executives and clients, and create an environment where all stakeholders, including site staff, can engage positively. Appointing a top-down promoter (CIM promotion leader) to drive the effort is effective.

• Prepare necessary resources and tools: Provide software for handling 3D models, high-performance PCs, tablets, and other ICT equipment. If there is no in-house expertise, use external support and training to develop staff skills. Even small companies can now start with lower upfront costs thanks to cloud services and simplified surveying tools (such as LRTK described below).

• Establish data standards and operational rules: When multiple contractors or departments are involved, decide in advance the model formats, naming conventions, and version control rules. Refer to the Ministry's "CIM Implementation Guidelines" and industry standards (such as IFC) to create a data environment that anyone can use. Define the scope of attribute information input and update procedures to help later phases.

• Run a pilot project: Rather than rolling out to all projects at once, begin with a small-scale project or internal test to experience the CIM workflow. Start small, learn from lessons, and transition gradually to full adoption to reduce resistance on site and facilitate smooth diffusion.

After these preparations, you can begin concrete CIM utilization in each process. The next chapter explains checklist points for the design, construction, and maintenance phases.

CIM Utilization Checklist for the Design Phase

In the design phase, the focus is on creating the 3D models that form the foundation of CIM and adding information. Reconsider the traditional 2D drawing-centered design work and use the following checklist to leverage CIM.

• Collect as-built data and model it: Accurately understanding the existing terrain and structures of the project site is the starting point. In addition to existing documentation, obtain point cloud data via drone photogrammetry or terrestrial laser scanning as needed, and create 3D models of the current topography and existing structures. This aligns the design model to the actual terrain and prevents discrepancies in later stages.

• Design centered on 3D models: Use civil CAD or BIM-compatible software to create detailed 3D models of structures and earthworks. By examining and placing design elements in three dimensions rather than just plan and section views, you can intuitively grasp grade separations and interfaces with surrounding features. Add attribute information such as material, dimensions, and quantities to the model so it can be used later for quantity estimation and construction planning.

• Model review and quality checks: Once the design model is complete, conduct reviews with stakeholders. Perform interference checks (clash checks) between structures and the surrounding terrain within software to prevent design errors. Also verify that the model meets standards and client requirements and that required attributes are fully included. Using tools like the Ministry's "design review sheet" helps prevent omissions.

• Share models with stakeholders: From the design stage, share models with clients and other departments to get feedback. Present 3D models rather than drawings during meetings so everyone has the same spatial image. Incorporating contractor input early prevents rework such as "we can't build it as designed." Use dedicated viewers or cloud services to facilitate model sharing.

• Use models for quantity estimation and simulation: Completed CIM models are useful for estimating and quantity calculations. Automatically derive earthwork volumes and component quantities from the model to reduce manual work, and perform construction simulations as needed (4D models: 3D + time) to verify temporary works and schedule plans. These uses allow you to experience CIM benefits (efficiency and accuracy) from the design stage.

CIM Utilization Checklist for the Construction Phase

In the construction phase, maximize the use of design models on site to improve productivity and ensure quality. Use the following checklist to adopt new digital construction methods.

• Digital surveying and as-built management: Use ICT for layout and staking before construction and for intermediate checks and as-built confirmation. Specifically, use total stations and GNSS surveying equipment to accurately output model coordinates to the site or to measure as-built conditions and compare them with the model. For large-scale embankment and excavation, combining GNSS-based height measurement allows a single person to efficiently check ground elevations instead of using traditional leveling. Lately, drone and terrestrial LiDAR point cloud measurement of intermediate earthwork volumes and shapes, and visualizing differences from the design model, have become common.

• Use machine guidance and machine control: Integrate 3D design data into construction equipment such as bulldozers and excavators so operators can work using coordinate information. Display design surfaces and structure models on the equipment monitor so even non-experts can perform accurate excavation and embankment without relying on intuition. With modern machines equipped with machine control, excavation and grading proceed under automatic control according to the set design surface, dramatically improving efficiency and accuracy.

• AR-supported construction: Use AR functions on tablets or smart glasses to overlay design models on site. For example, visualizing the installation position of a structure with AR enables accurate staking and placement even without survey technicians. For rebar placement, display a virtual rebar model in AR at the planned positions and immediately verify alignment with the actual rebar. For buried works, checking the as-built image in AR before backfilling helps detect mistakes or omissions early. AR construction support greatly improves the accuracy of building the site "as designed," reducing rework and material waste.

• Digital visualization of progress and quality control: Integrate daily production data and quality inspection results into the CIM model to support real-time progress management. For instance, overlay point cloud as-built data on the model and color-code construction progress, or link inspection results to parts of the model for record-keeping. This allows both the site office and headquarters to intuitively grasp the construction status in 3D and respond early to schedule delays or quality issues. Presenting the model makes reporting to clients and internal sharing easier and smooths information transfer.

• Strengthen information sharing among stakeholders: In the construction phase, a wide variety of stakeholders—from site agents and foremen to designers and clients—are involved. Using the CIM model as a common language prevents communication loss. Keep the latest model synchronized on tablets and use it in site meetings. For remote stakeholders, use the model for online meetings and remote visual inspections to share site conditions across distances. For local residents, projecting the completed image with AR at the site during briefings can help gain understanding and cooperation. CIM data becomes a common platform connecting site and office, client and contractor, supporting smooth decision-making.

CIM Utilization Checklist for the Maintenance Phase

After handover, leveraging CIM for maintenance enables lifecycle-wide efficiency. To extend the service life of completed structures and reduce maintenance costs, check the following points.

• Handover of the as-built model and information transfer: Ensure the latest 3D model updated during construction and associated information are handed over to the maintenance department and the client. Deliver the CIM model itself in addition to drawings and documents so it can be used as a digital twin of the completed structure. Link as-built drawings, inspection results, and quality records to the model for later reference.

• Use in inspection planning: Use data in the CIM model for planning inspections and repairs. Referencing component data registered in the model (material, standards, service life, etc.) makes it easy to identify vulnerable parts and replacement timing. For example, the timing for inspecting or replacing bridge cable tension can be derived from the data. Overlaying past deterioration records on the model allows you to compare changes in 3D at the next inspection, aiding assessment of deterioration progression.

• Point cloud measurement and displacement monitoring in maintenance: Periodically scanning structures post-operation with point clouds can detect small deformations or damage. In tunnels and slopes, comparing point clouds from periodic 3D scans with past data to visualize displacement is already being implemented. Monitoring by comparing the CIM model with actual conditions enables early detection of abnormal signs and supports preventive maintenance. Recently, drone and simple GNSS-equipped devices have made rapid point cloud acquisition accessible to anyone.

• AR-supported maintenance: AR technology is effective for inspection and repair work. By pointing a smart device to see through and display internal arrangements of a structure, workers can, for example, identify buried pipes or steel placement before excavation or drilling. Displaying inspection locations with AR markers during patrols prevents oversights and enables efficient inspections. Because field workers can intuitively reference knowledge accumulated in the CIM model, even less experienced staff can perform high-quality maintenance.

• Centralized data management and utilization: Maintenance involves handling large volumes of data such as inspection results and repair histories. Positioning the CIM model as an asset management platform for centralized management is convenient. Link and store inspection photos and report PDFs to the relevant parts of the model, reflect deterioration prediction simulations in the model, and organically connect digital data. This data-driven approach transforms traditionally person-dependent maintenance tasks into planned, efficient infrastructure management.

Points for Utilizing Point Cloud Data

Point cloud data utilization is inseparable from CIM. Point clouds (3D data consisting of many points obtained from laser scanners or photogrammetry) record the shape of existing conditions in detail and bridge models and reality. Keep these point cloud usage points in mind for each phase.

• Design phase: Acquire point clouds of terrain and existing features around the project site and use them as the basis for design. Large-area terrain surveys can be made efficient with drone photogrammetry; generate contours and surface models from the resulting point cloud to enable design on a high-accuracy terrain model. For bridges and rivers, scanning the surrounding environment with laser scanners helps check clearances with nearby structures and supports landscape simulations.

• Construction phase: Use point clouds for as-built management and progress confirmation during construction. For example, in tunnel work, laser-scan the tunnel cross-section after each excavation and compare to the design shape to immediately check for over-excavation or under-excavation. In paving works, measure the surface with point clouds before and after laying to evaluate flatness, and incorporate 3D data into quality control. Some projects acquire a complete point cloud of the finished structure with drones and submit it to the client as objective evidence of as-built conditions.

• Maintenance phase: As noted above, point clouds are powerful for periodic inspections and disaster surveys. Scanning structures after earthquakes or typhoons can quantify and record deformation amounts at damaged locations. Because point cloud data can be compared across years, it has great value as time-series data for maintenance. Recently, tablet devices with mobile LiDAR or smartphone camera-based simple 3D scanning have matured, lowering the barrier to point cloud acquisition.

• Data management and utilization methods: Point clouds are large and can be difficult to handle. Convert them into mesh models by feature or thin out points to lighten files according to the use case. Aligning point clouds with the CIM model (georeferencing) is also important. Standardize coordinate systems and set up an environment where models and point clouds can be overlaid and compared. This enables advanced uses such as verification through virtual construction and automated as-built evaluation.

Efficiency Gains from GNSS Surveying and AR Construction Support

To extract CIM benefits quickly, it is key to use the latest technologies on site. Particularly noteworthy is the combination of GNSS surveying and AR (augmented reality) construction support. Using these technologies makes high-precision surveying and construction possible even for non-experts, greatly lowering the barrier to CIM adoption.

GNSS surveying is a method that uses satellite positioning systems such as GPS. RTK (Real-Time Kinematic) technology, which compares base station and rover data in real time, can measure current position with several-centimeter accuracy (cm level accuracy, half-inch accuracy). Traditionally, high-precision surveying required specialized surveyors and total station equipment, but recently affordable systems combining high-performance compact GNSS receivers and smartphones have appeared. For example, using *LRTK* (a smartphone-mounted RTK-GNSS solution) lets someone bring a smartphone with an antenna to the site and press a button to obtain latitude, longitude, and height of a point. Because it enables rapid single-person elevation checks and layout of structures over large development areas, work delays due to waiting for surveying are reduced.

AR construction support overlays 3D models on the real-world view through a tablet or smartphone screen. As mentioned earlier, AR at the construction site allows intuitive understanding of the finished shape that is hard to perceive from drawings, which is very effective in reducing mistakes and improving communication. However, general AR apps have had the drawback that model placement (calibration) on site is time-consuming. If you do not adjust reference markers and the virtual model each time, the model will not be overlaid in the correct position, so operating it required skill.

Combining GNSS and AR solves this issue. *LRTK* is a prime example: it uses accurate coordinates from an RTK-GNSS receiver attached to a smartphone to automatically display 3D models at the correct real-world position and scale. Because tedious positioning work is unnecessary, as soon as you arrive on site the structure model or design lines appear on the phone screen in the right place. For example, you can overlay the finished terrain model on a development site and have an operator visually adjust the heights to cut, or project a life-size model on a pier installation site to guide crane operations—the applications are wide-ranging.

These technologies that combine GNSS surveying and AR construction support are being adopted not only by large construction firms but also gradually on small and medium sites. The ease of "anyone with a smartphone can perform surveying and AR confirmation" is a boon to an industry suffering from severe labor shortages. Systems like LRTK also support cloud integration, allowing site-acquired coordinates and point clouds to be saved to the cloud and shared with the office. This enables real-time integration of CIM models with site-measured data and rapidly realizes higher-precision construction management.

Conclusion: Achieve Fast CIM Results with LRTK

This CIM utilization checklist covered key points to address in the design, construction, and maintenance phases. Although CIM adoption may seem daunting at first, you can achieve steady results by organizing tasks by phase and using appropriate tools. Actively adopting technologies such as GNSS surveying and AR is the key to drawing out CIM’s benefits as quickly as possible.

Now that user-friendly solutions like *LRTK*, which combine smartphones and small devices, have emerged, applying CIM on site has become more accessible than ever. By using LRTK, even without skilled surveyors you can perform high-precision as-built measurements and AR-based construction verification with your own staff, allowing small companies and regional sites to enjoy the benefits of digital construction. Cases have emerged where mastering the latest tools compatible with the Ministry’s i-Construction initiative has led to significant schedule reductions and cost savings compared to traditional methods.

What matters is not just introducing technology, but integrating it into work flows and using it effectively. Use this checklist to develop a CIM utilization plan suited to your projects and start with what you can do now. With CIM and LRTK as your allies, moving to consistent digital construction from design through maintenance will surely deliver remarkable efficiency and quality improvements. Bring the latest technology to your site, achieve results quickly, and ride the wave of construction DX!