What can point cloud data of Important Cultural Properties be used for? Explaining 7 use cases

In practical work related to the preservation and investigation of Important Cultural Properties, it is not uncommon to encounter challenges that cannot be fully understood through drawings and photographs alone. The more one tries to accurately understand a subject—its complex design details, years of deformation, subtle misalignments between components, its relationship with the surrounding terrain, pre- and post-repair comparisons, and decisions about restoration after disasters—the more the limitations of two-dimensional records become apparent. What has therefore attracted attention is point cloud data, which can record an object's shape and positional relationships in three dimensions.

The reason point cloud data is required at sites of Important Cultural Properties is not simply "to create a beautiful three-dimensional model." It is because it can be used as foundational information for a series of tasks: conservation, repair, documentation, public exhibition, and future stewardship. What practitioners really want to know is in which situations point cloud data is useful, what changes when it is introduced, and to what extent it can be reused.

This article explains, from a practical standpoint, how point cloud data for Important Cultural Properties is used in various situations by dividing the discussion into seven use cases. It also organizes the concepts you should grasp before introduction and the approaches to fully leverage the data. The content is compiled so that those responsible for surveying, conserving, maintaining, and planning improvements for Important Cultural Properties can concretely envision how to use point cloud data.

Table of Contents

• Reasons why point cloud data of Important Cultural Properties is attracting attention

• Use case 1 Record current conditions with high precision

• Use Case 2: Useful for Assessing Deformation and Deterioration

• Use Case 3: Informing Repair Planning and Construction Considerations

• Use case 4: For recording and recovery decision-making during disasters

• Use Case 5 Public Use and Development into Exhibition Materials

• Use case 6: Leverage in preservation management that includes the surrounding environment

• Use Case 7 Helping pass on to the future and share with stakeholders

• Approaches to Successfully Utilizing Point Cloud Data of Important Cultural Properties

• Summary

Why Point Cloud Data for Important Cultural Properties Is Attracting Attention

Important cultural properties differ from ordinary buildings or structures and cannot be addressed by simple updates or renovations alone. With preservation as the premise, it is necessary to accurately ascertain the current condition, carefully consider any required treatments, and keep a record of the work carried out. For that purpose, it is essential to document the condition of the property in as objective and as reusable a form as possible.

Traditionally, information about Important Cultural Properties has been accumulated through measured drawings, photographs, registers, and repair records. However, complex roof shapes, ornamentation involving curved surfaces, columns and beams altered by aging, slight tilts or sags, and conditions in narrow or elevated areas can sometimes be difficult to adequately share with only limited sectional drawings and photographs, and each time the person in charge changes the effort required for on-site confirmation may increase and the assumptions underlying judgments may differ from person to person.

Point cloud data has the advantage, for such challenges, of being able to record objects as three-dimensional coordinate information. Because it can preserve the shape itself over a wide area, it is easy to broaden its applications — for example, by cutting cross-sections later to inspect them, checking dimensions of necessary parts, or comparing data from different times. For subjects that are monitored over long timeframes, such as Important Cultural Properties that are not finished with a single survey, this ability to be used repeatedly afterward is extremely valuable.

In addition, the management of Important Cultural Properties involves many stakeholders, such as surveyors, conservation staff, designers, construction staff, owners, and administrative officials. Point cloud data also serves as a foundation for people from different specialties to view the same subject with a shared understanding. Being able to share, visually and quantitatively, subtle deformations and spatial relationships that are difficult to convey with words alone is also effective for consensus building.

Point cloud data for Important Cultural Properties becomes easier to recognize in value when it is positioned not merely as an enhancement of documentation but as a common foundation that supports the entire process of preservation and utilization. From here, we will look concretely at seven use cases to see the kinds of situations in which it is actually used.

Use Case 1: Record current conditions with high precision

The most fundamental and important use case is recording the current condition. For Important Cultural Properties, preserving the present state as accurately as possible is itself highly significant. It not only serves as baseline documentation for future repairs and investigations, but also becomes the starting point for tracking changes over time.

The advantage of recording current conditions with point cloud data is that it can preserve the entire object's shape as surface-based, three-dimensional information. The building's overall exterior, interior spaces, the arrangement of columns and beams, ceiling heights, floor unevenness, and the relief of decorative elements can all be stored in a state close to what was seen on site. Fine details that are not represented on drawings also tend to be retained in the data, and the ability to re-check them later is a major strength.

For Important Cultural Properties, past drawings and records are sometimes not sufficiently preserved. Even when drawings exist, they may not correspond to the current condition. This is because past repairs, replacement of structural members, settlement, tilting, and other factors can cause the present appearance to differ from how it looked when the records were made. Therefore, accurately ascertaining the current condition with high precision has significant practical value.

Furthermore, point cloud data can help reduce the number of site revisits. Of course, there are situations where an on-site inspection is necessary for the final decision, but it can lessen the need to go back to the site repeatedly just to recheck dimensions or clarify spatial relationships. This advantage is particularly significant for high locations or areas that require scaffolding, interior spaces with access restrictions, and places where access conditions change depending on the season or events, where securing high-density data during the initial survey is beneficial.

Point cloud data as a record of the current condition is not merely archival material. It is a foundation that can be used for subsequent work. For Important Cultural Properties, the starting point is first "how accurately can the existing appearance be preserved?", so it is easy to understand if you consider the use of point cloud data as beginning at this stage.

Use Case 2: Useful for assessing deformation and deterioration

For Important Cultural Properties, it is necessary to continuously monitor deformation, sagging, tilting, settlement, displacement of components, surface wear, and other changes caused by aging and environmental influences. Such changes can be difficult to quantify from photographs alone, and drawings alone may make it hard to understand their relationship to the whole. Point cloud data captures shape in three dimensions, making it effective for detecting deformations and deterioration.

For example, the tilt of columns, unevenness of floor surfaces, sagging of roofs, bulging of walls, and displacement of masonry are easier to identify by examining cross-sections derived from point cloud data. The important point is not just seeing where the damage is, but grasping how it relates to the overall structure and surrounding members. What appears to be a local anomaly may actually be part of a deformation trend affecting the entire building.

Also, by comparing point cloud data acquired at different times, it becomes easier to track trends in changes over time. Even if no large changes are immediately apparent, displacements and deformations that are progressing gradually may be confirmed when viewed over several years. In the preservation of important cultural properties, it is important not only to detect sudden damage but also to avoid overlooking gradual changes. In that sense, point cloud data can be utilized as a foundation for condition monitoring.

Of course, point cloud data alone cannot identify all causes of deterioration. The internal condition of materials, moisture content, decay, and subsurface anomalies must be assessed in combination with other inspection methods. However, point cloud data makes it easier to clarify which areas should be investigated in more detail and the extent over which changes are occurring. It is also useful for prioritizing investigations.

The preservation of Important Cultural Properties should not be about responding after anomalies occur, but about detecting signs of change and preparing for them. To do so, it is necessary not only to rely on sensory perception but also to record condition in a form that can be compared. Point cloud data is precisely an information asset that can fulfill that role.

Use Case 3: Applying to Repair Planning and Construction Considerations

When repairing Important Cultural Properties, it is necessary to carefully formulate plans without placing unnecessary loads on the object and after thoroughly understanding its current condition. Point cloud data can play a major role at the stages of repair planning and construction review.

First, as a prerequisite for repair design, it is important to accurately ascertain the as-built dimensions and member layout. Important Cultural Properties often contain subtle misalignments and deformations, even if they appear visually symmetrical. If drawings are prepared based on off-the-shelf assumptions, they may not align with conditions on site and may require reconsideration. Referring to point cloud data during the study makes it easier to develop a plan that corresponds to the actual conditions.

It is also useful for planning scaffolding and examining work flow. Conditions such as narrow interior spaces, low ceilings, surrounding trees or stone walls, and limited access routes are common with Important Cultural Properties. With point cloud data, it becomes easier to verify spatial constraints not only for the target but also for the surrounding conditions, helping to reconcile safety and efficiency in construction.

It is also useful as comparative documentation before and after repairs. If you can preserve not only plans and photographs but also three-dimensional information about where and how repairs were made and the condition of each component, the accuracy of construction records will improve. If future repairs become necessary, it will also make it easier to trace past decisions and the actions taken.

Furthermore, point cloud data is also useful as explanatory material for stakeholders. In the restoration of Important Cultural Properties, even experts can have different perspectives. This is because the issues are divided into multiple points—positions that emphasize structural aspects, positions that emphasize preservation of design, positions that emphasize ease of maintenance, and so on. In such cases, being able to share the space and shapes based on point cloud data makes it easier to establish a common basis for discussion.

The reason point cloud data is useful in repair planning is not simply that it looks good in three dimensions. It enables assessments that faithfully reflect current conditions, reduces discrepancies with the site, and provides a shared basis for explanations. This value is even higher for assets where the burden of rework is large, such as Important Cultural Properties.

Use Case 4: Recording and Recovery Decision-Making During Disasters

Important cultural properties are exposed to various disaster risks such as earthquakes, heavy rain, typhoons, falling snow, and landslides. After a disaster, confirming safety is the top priority, but thereafter the process continues with damage documentation, emergency response, and consideration of restoration policies. At this stage, whether point cloud data is available can greatly affect the ease of decision-making.

If point cloud data from before the disaster is available, it becomes easier to compare it with the post-disaster condition and determine where and how much change has occurred. Changes that are difficult to judge from photos alone—such as roof sagging, wall displacement, collapse of stone walls, and the relationship with the ground—are easier to assess from a comparative perspective. For Important Cultural Properties, it is extremely important in restoration to determine "to what extent the original condition can be referenced." As foundational documentation, point cloud data holds great significance.

It is also useful as a record immediately after a disaster. As time passes, emergency measures and cleanup will erase the condition that existed right after the damage. If point cloud data can be acquired early while ensuring safety, it can be used as objective material for restoration design and archival preservation. This is especially valuable when there is a risk of further collapse or deformation, making it important to preserve shape information at an early stage.

Furthermore, it helps prioritize recovery. Because it enables a three-dimensional understanding of which parts have deformed the most, where there is a risk of secondary damage, and how these relate to the surrounding topography and drainage conditions, it provides a basis for planning emergency responses. Important cultural properties require attention not only to their cultural value but also to safety, and objective decisions must be made within the limited time available.

In disaster response, the availability of records prepared during normal times can determine how the subsequent response proceeds. Point cloud data functions as documentation for preservation and management in normal times and as a baseline for comparison in emergencies. For important cultural properties, point cloud data also serves as a foundational record connecting normal times and emergencies.

Use Case 5: Deploying for Public Use and Exhibition Materials

Point cloud data of Important Cultural Properties is useful not only for preservation and repair but also for public utilization. While it is important to convey the value of Important Cultural Properties widely, on-site public access involves many conditions such as safety, visitor circulation restrictions, preservation environment, and access limitations. Therefore, not all visitors can necessarily view the actual objects sufficiently. Point cloud data serves as material to deepen understanding of their value while compensating for these constraints.

For example, high areas that are normally inaccessible, narrow interior spaces, or parts that are difficult to open to the public for preservation reasons can be presented three-dimensionally based on point cloud data, making it easier to convey the structural and design characteristics of the subject. Compared with a simple photographic display, this approach more readily leads to an understanding of the entire space and provides material that visitors and learners can grasp more easily.

It can also be used for before-and-after comparisons of repairs and for explaining structural relationships that are not normally visible. The value of Important Cultural Properties lies not only in the beauty of their appearance but also in their historical techniques, composition, relationship with the land, and the changes accumulated over long periods of time. By utilizing point cloud data, it becomes easier to convey that background information in three dimensions.

They are also well suited for educational purposes. They can be used not only as detailed materials for specialists but also organized in ways that are easy for the general public to understand. In contexts such as school education, community learning, and preservation awareness, they serve as an entry point for understanding the subject in three dimensions. While prioritizing the preservation of the physical objects, they can act as a bridge to convey their value to a wider audience.

When making Important Cultural Properties publicly accessible, it is more important to convey their value accurately without diminishing it than to use flashy presentation. In that sense, point cloud data is a material that easily balances recordability and explainability. The fact that data acquired for preservation spreads into education and public outreach is a major advantage.

Use Case 6: Applying to preservation management including the surrounding environment

The value of an Important Cultural Property does not necessarily lie solely in the building or structure itself. Topography, approach paths, stone steps, stone walls, gardens, drainage routes, the sense of distance to surrounding buildings, the way views open up, and other aspects of the surrounding environment often form part of that value. Therefore, in preservation management it is necessary to understand not only the individual property but also its relationship with the surrounding context.

Point cloud data is well suited for recording the surrounding environment. If you capture the target object together with the surrounding terrain, it becomes easier to estimate slopes, elevation differences, and water flow, and it also helps in considering drainage plans and disaster-prevention measures. In cases where Important Cultural Properties stand on slopes, or where their relationship with stone walls and retaining walls is important, being able to grasp the surroundings is particularly significant.

It is also useful when assessing the effects of tree growth and nearby facilities. It makes it easier to organize issues that are hard to discern from drawings of the object alone, such as sunlight, ventilation, visibility, and accessibility. Decisions related to preservation are often not sufficient if you look only at the object itself. Only by examining the surrounding conditions as well can you begin to more easily establish effective management policies.

It is also useful for creating plans for maintenance and management. Practical decisions—such as which route to take for inspections, where to place temporary facilities, and which areas to monitor closely—become easier the more comprehensively you understand the space. In the management of important cultural properties, small judgment errors can lead to large burdens, so having spatial information is highly valuable.

If point cloud data is regarded as "data of the building only," its uses are limited; if, however, it is regarded as "a foundation for preservation and management that includes the surrounding environment," its potential uses expand greatly. To protect the intrinsic value of Important Cultural Properties, a perspective that includes the environment in which they are situated is necessary.

Use Case 7: Facilitating Future Succession and Sharing with Stakeholders

The management of Important Cultural Properties cannot be completed with a single survey or a single repair. Personnel change, ownership and managing entities change, and the organizational structures of related institutions evolve. In such circumstances, if information handover is insufficient, the context behind past decisions can become unclear, the same verification work may be repeated, and consistency in preservation can be compromised. Point cloud data is also effective in addressing these problems of information transfer and sharing.

With point cloud data, it becomes easier to share the spatial characteristics of a subject that are difficult to convey with text alone with successors and external stakeholders. Even personnel with little on-site experience can more easily grasp the overall picture and key areas of the subject, improving the quality of handovers. In particular, being able to preserve records of pre-repair conditions and the state of restricted-access areas is important for long-term management.

Additionally, it also serves as a common reference when stakeholders from multiple disciplines handle the same subject. The information needed by those responsible for preservation, design, construction, management, and education differs slightly, but point cloud data forms the foundation. Because cross-sections can be checked and spatial relationships can be shared as needed, it becomes easier to align the starting point for explanations.

It also has value as preparation for future re-surveys or re-repairs. Even if ways to make use of it are limited at present, it is entirely possible that it will be needed later for other purposes. The preservation of Important Cultural Properties is a long-term effort, and it is important not to judge value solely by current tasks. Leaving information in a form that future custodians can use is itself part of preservation practice.

Point cloud data of Important Cultural Properties is an asset that helps not only to address immediate challenges but also to pass information on to future generations. The shape information collected on site plays a major role in ensuring that knowledge is preserved not as individual experience but as organizational and regional expertise.

Approach to Successfully Utilizing Point Cloud Data of Important Cultural Properties

We have looked at seven use cases so far, but to actually make effective use of point cloud data, it is important not to treat acquisition as an end in itself. At important cultural properties sites, it can happen that data are collected but not used much afterwards. To prevent that, it is necessary to clearly define from the outset what the data will be used for.

For example, whether the primary purpose is to record current conditions, to plan repair designs, to serve as a benchmark for disaster comparisons, or to include the surrounding environment will change the required scope and density as well as the approach to data acquisition. While it is important to adopt a perspective that broadens the potential for later use, the top priority is to develop a plan that fully meets the objectives.

Additionally, the way coordinates and positional references are conceived is important. When documenting Important Cultural Properties, you need to consider not only the shape of the object itself but also consistency with future re-measurements and with surrounding information. If there is any possibility of making later comparisons or linking the record to other survey results, the handling of positional information should be clarified at an early stage. That will significantly affect its future reusability.

Moreover, it is essential to be aware of who will use the point cloud data and how. Whether it will be used only by specialists, shared with administrative staff, or considered for educational use will affect how the results are compiled and stored. By thinking not only about the point cloud data itself but also, when necessary, about turning it into drawings or explanatory materials, you can broaden the range of its applications.

For Important Cultural Properties, it is not enough to pursue accuracy alone, nor to emphasize readability alone. It is important to preserve information in a form that is useful for preservation practice and can be used continuously. To achieve this, it is necessary to consider the pre-acquisition design, post-acquisition organization, and methods of sharing as an integrated whole.

Summary

Point cloud data of Important Cultural Properties are not merely three-dimensional records. They are foundational information that supports a wide range of tasks—understanding current conditions, checking deformations, planning repairs, responding to disasters, public use, preservation management including the surrounding environment, and transmission to future generations. Because Important Cultural Properties must be considered not only in terms of preserving their present appearance but also how to pass them on to the future, the significance of having records that can be reused repeatedly later is very great.

What is particularly important for practitioners is not the act of capturing point cloud data itself, but how it will be used for subsequent decision-making and sharing. By keeping in mind why you collect it, what scope you cover, how you store it, and with whom you share it, point cloud data becomes truly actionable information. To make the preservation and utilization of Important Cultural Properties more reliable, organizing point cloud data with an awareness of its intended use will become increasingly important going forward.

And in surveys and preservation management of Important Cultural Properties, it is essential not only to have point cloud data but also to secure accurate location information on site. Checking control points, ascertaining on-site coordinates, carrying out local positioning work around the site, and aligning the positions of recorded subjects—making three-dimensional data useful in the field becomes much easier when there is a reliable positioning infrastructure. In such situations, using high-precision positioning devices like LRTK that can be attached to an iPhone can help streamline on-site verification and simple surveying. Even at sites like Important Cultural Properties where careful documentation and positional consistency are required, having an environment where coordinates can be quickly confirmed where needed is a major aid to the practical use of point cloud data.