Is a 3D Laser Scanner Effective for Cultural Property Preservation? Explaining Four Differences from Photography

In the field of cultural property preservation, a major challenge is how to record objects, how to preserve them, and how to link those records to future management and repairs. Temple and shrine architecture, stone walls, stone monuments, civil engineering heritage, historic buildings, and ruins are not sufficiently served by preserving appearance alone. It is necessary to grasp, in three dimensions and objectively, where tilting exists, where losses or wear occur, which parts are deformed, and how the surrounding topography and structures relate. For this reason, in recent years interest has grown in three-dimensional recording using 3D laser scanners in addition to traditional photographic records.

On the other hand, from the perspective of practitioners, questions often arise such as whether photographs alone are sufficient, whether a 3D laser scanner is truly necessary, or whether it will be underutilized even if introduced. In practice, cultural property preservation involves many stakeholders across surveys, recording, design, repairs, maintenance, and preparation of explanatory materials, and simply using a new device does not by itself solve everything. What matters is correctly understanding the different roles of photography and 3D laser scanning and using each according to the object and purpose.

This article organizes whether 3D laser scanners are effective in cultural property preservation and then explains, in four items, the differences from photography in an easy-to-understand way. It is carefully summarized from a practical viewpoint for those who want to review recording methods, strengthen their understanding of conditions before repairs, or consider future comparisons and drawing up plans.

Table of Contents

• Why 3D laser scanners are attracting attention in cultural property preservation

• Are 3D laser scanners effective for cultural property preservation?

• Difference from photography 1: Quality and quantity of recordable information

• Difference from photography 2: Ease of shape reproduction and temporal comparison

• Difference from photography 3: Ease of conversion to drawings, measurement, and sharing

• Difference from photography 4: Preservation management and expansion of future uses

• Situations where 3D laser scanners are particularly powerful

• Practical precautions to keep in mind when introducing them

• Improving accuracy in cultural property preservation also requires organizing site positional information

Why 3D laser scanners are attracting attention in cultural property preservation

The purpose of recording in cultural property preservation is not simply to leave images for introduction. It is to objectively capture the current condition, preserve it so that it can be compared with future changes, and make it usable as a basis for repairs or investigations when necessary. No two cultural properties are identical, and preservation environments and degradation processes vary greatly by object. Information needed for preservation decisions—such as warping of wooden parts, weathering of stone, surface peeling, structural settlement, and elevation differences with surrounding ground—often cannot be fully captured by two-dimensional images alone.

This is where 3D laser scanners demonstrate their strengths: they acquire a large number of positions within a space and record them as three-dimensional shapes. Because countless points on the target surface are obtained with coordinates, it becomes easier afterward to check heights, distances, misalignment of surfaces, cross-sectional shapes, deflection, tilt, and so on. Methods that preserve appearance, such as photography, are of course important, but photographs are fundamentally viewpoint-dependent records. Viewing angle, shooting distance, lens characteristics, shadows, and ambient light conditions can easily change impressions, and additional aids are needed to grasp dimensions and shapes.

At cultural property sites, photographs may be sufficient during the survey stage, but more accurate shape records are often required when actually advancing repair plans. Stakeholders often want to compare before and after repairs, share the same current condition among participants, obtain cross sections or elevations, explain the amount of deformation, or compare under the same conditions in future re-surveys. At that time, two-dimensional images have limitations, and the need for three-dimensional data grows rapidly.

Furthermore, re-entering a site multiple times can be difficult in cultural property preservation. There may be strict access conditions, limited scaffold periods, only a short pre-disassembly window to observe, or an inability to recheck the same state later due to disasters or progressing degradation. For this reason, how much information can be captured in a single site visit is important. 3D laser scanners are drawing attention as a method that mitigates information loss in such one-off situations.

Are 3D laser scanners effective for cultural property preservation?

In conclusion, 3D laser scanners are highly effective for cultural property preservation. However, they do not completely replace photography in all situations, and it is essential to understand that their roles differ. What really matters in practical cultural property preservation is not simply deciding which is superior, but organizing what is needed for each purpose.

The main reason 3D laser scanners are effective is that they can record shapes as quantitative data. For example, unevenness of stone steps, bulging of wall surfaces, tilting of pillars, flooring settlement, and displacement of revetments can often be recognized as abnormalities in photographs alone. Yet when you try to quantitatively show how much displacement there is, where the differences are largest, or how much improvement occurred after repair, photographs alone tend to lack persuasive power. With three-dimensional data, you can slice cross sections for comparison, check distances between arbitrary points, and grasp surface variability, greatly increasing the basis for decision-making.

Moreover, consensus-building among stakeholders is important in cultural property preservation. Owners, managers, preservation staff, surveyors, designers, contractors, administrative officials, and researchers—people in different roles—discuss the same object. Photographs are intuitive and easy to understand, but because viewpoints are limited, perceptions can differ among people. Three-dimensional data allows the same object to be checked from different angles, required cross sections to be produced, and explanations to be accompanied by numerical data, which helps reduce discrepancies in understanding.

That said, photographs remain important for visual information such as surface color, patterns, material texture, appearance of degradation marks, and legibility of inscriptions. For routine inspections, public relations records, or uses that only require quickly conveying the current condition, photographs may be sufficient. Not all cultural properties require large-scale three-dimensional measurement at all times. What is important is to judge necessity from the perspective of how much shape needs to be preserved, whether future comparisons are possible, and whether one envisions conversion to drawings or repair review. In other words, a 3D laser scanner is not a universal replacement but a powerful option to enhance the accuracy and reusability of preservation records.

In cultural property preservation, it is important to separate visual information from shape information. The former is suited to photography, the latter to 3D laser scanning. Only when both are available does it become easier to understand the current condition from multiple perspectives. Therefore, the appropriate answer to whether 3D laser scanners are effective is not to deny photography, but to say they are effective as a means to complement the parts that photographs tend to miss and to raise the overall quality of preservation records.

Difference from photography 1: Quality and quantity of recordable information

The biggest difference between photography and 3D laser scanning is the content of the information recorded. Photographs record appearance from a given viewpoint as a two-dimensional image based on light information. They make it easy to grasp color, patterns, surface dirt, how inscriptions or designs appear, and the surrounding atmosphere, and are indispensable for on-site confirmation and reporting materials. Especially for cultural properties, recording surface wear, ornamentation, and material texture is important, and the value of photographs is very high.

On the other hand, 3D laser scanners record shape as three-dimensional coordinate information based on distances and positional relationships to the target. They capture not only visual impressions but also spatial information about what undulations exist, which faces orient which way, and where steps or deformations occur. In other words, photographs are strong for visible information, while 3D laser scanners are strong for shape information.

This difference has great significance at cultural property sites. For instance, for stone monuments or statues whose surfaces are heavily worn and whose inscriptions or carvings are difficult to see, photographs can change impressions depending on lighting and shooting angle. With three-dimensional data, however, surface relief can be inspected in another way, making it easier to assess the degree of wear and the residual shape. The same applies to pillars and beams in temple and shrine architecture: photographs are useful for color and surface damage, but warping, tilt, and positional relationships between members are easier to organize with three-dimensional information.

Also, the density of photographic records varies with where and how the photographer shoots. If necessary parts are omitted, they cannot be checked later. Experienced staff may capture important features, but when revisited for a different purpose later, it is not uncommon to find information missing that at the time seemed unnecessary. In contrast, 3D laser scanners can capture targets as surfaces, making it easier to check required positions afterward. Of course there are issues with blind spots and occlusions, but this method approaches comprehensive records that are less influenced by the photographer’s subjectivity.

In cultural property preservation it is important to preserve not only information needed now but also information that may be needed in the future. If only photographs are recorded, you cannot respond later when dimensions or cross-sectional information from different angles become necessary. With three-dimensional data, within the acquired range, post-processing can provide alternative views. This difference becomes more significant months or years after the initial survey than immediately afterward.

Furthermore, for cultural properties it is sometimes important to consider the relationship with the whole, not just a part of the object. For example, when evaluating the bulge of part of a stone wall, judgment can be difficult without seeing the surrounding continuous shape and the relationship with the ground. Photographs are excellent for partial records but are not good at quantitatively capturing relationships with the whole at the same time. 3D laser scanners make it easier to capture both detailed parts and the overall shape in the same coordinate system, making them well suited to practical cultural property preservation.

Difference from photography 2: Ease of shape reproduction and temporal comparison

In cultural property preservation, it is important not only to preserve the state at a given time but to be able to compare how it changes over time. You need to confirm whether degradation has progressed, whether repairs improved conditions, how much changed before and after a disaster, or whether new displacements have appeared in the ground or structures. Here there is a large difference between photography and 3D laser scanning.

You can compare past and present with photographs, but slight changes in shooting position, angle of view, focal length, weather, or shadows make it difficult to compare under the same conditions. Differences in appearance may simply be due to lighting conditions. Conversely, slight deformations can be hard to notice in photographs. Comparisons tend to rely on visual impressions and have limits for quantitative judgments.

Three-dimensional data obtained by 3D laser scanning, however, are strong because they are easy to compare when aligned to the same coordinate system or equivalent references. By overlaying past and current three-dimensional data, it becomes easy to see where and by how much differences have occurred. Differences that photographs make ambiguous—such as bulging of building facades, swelling of stone walls, ground surface settlement, or slight positional shifts of members—are easier to organize via three-dimensional comparison.

This feature is also effective for before-and-after repair comparisons. You can preserve where and to what extent deformations existed before repair, and how things settled afterward, as shapes. This not only improves the quality of construction reports and preservation records, but also provides material to decide which areas to focus on in the next survey. Cultural properties are long-term relationships; considering preservation history over decades, the value of comparable three-dimensional records is very high.

Ease of temporal comparison also leads to early detection of anomalies. Large damage does not occur at every inspection. It is important not to overlook very small changes such as slight settlement, progression of cracks, movement of stones, or displacement of members. By continuously accumulating three-dimensional data, it becomes easier to capture signs before anomalies fully manifest. This aligns well with a preventive maintenance approach and is highly meaningful for long-term protection of cultural properties.

Comparisons using photographs are not meaningless; rather, changes in discoloration, dirt, and surface condition are sometimes easier to recognize in images. However, when you need to demonstrate shape changes with evidence, three-dimensional comparisons exert strong power. Because cultural property preservation must track both visual and shape changes, combining photographs and 3D laser scanning makes it easier to improve comparison accuracy.

Difference from photography 3: Ease of conversion to drawings, measurement, and sharing

In practical cultural property preservation, records obtained on site are rarely just looked at and left as-is. They are processed and used in various forms such as survey reports, drawing production, repair planning, meeting materials, explanatory materials, and future verification. Regarding this ease of reuse, photography and 3D laser scanning play different roles.

Photographs are excellent as explanatory materials because they convey the scene to stakeholders in an easily understood visual way. However, when it comes to dimension checks, cross-section creation, elevation organization, or quantifying deformation—i.e., converting into drawings or numerical data—additional work is required. Even with scale bars, there are limits, and for complex-shaped cultural properties it is not easy to produce accurate drawings from photographs alone.

Data acquired by 3D laser scanners are handled as point clouds or three-dimensional models, which makes it easier to proceed to plan views, elevations, cross sections, or dimension extraction for required locations. Of course processing and organization take effort, but because shapes are natively stored as coordinates, they can more readily be developed into drawings and analyses. For example, when you want to view cross sections of a stone wall at multiple locations, check variations in stair riser heights or treads, organize building exterior tilts, or grasp height relationships with surrounding ground, three-dimensional data provide a powerful foundation.

Ease of sharing is also important. In cultural property preservation, not everyone can visit the site. Not all stakeholders can inspect the site each time. Therefore, records that enable understanding of the condition without visiting the site are needed. Photographs are easy to understand but depend on shooting locations, so you cannot view another angle on demand. With three-dimensional data you can change viewing angles, cut sections, and zoom into required areas, making it easier to deepen understanding remotely.

This also affects decision-making speed. Contents that would require additional explanation with photographs alone can be shared more directly when combined with three-dimensional data, making it easier to understand where issues are and how much response is needed. In cultural property preservation, delays in decisions can lead to progression of degradation. Improving the quality of information sharing therefore raises the quality of preservation activities themselves.

Moreover, ease of conversion to drawings and measurement relates not only to external explanation but also to internal operational efficiency. If a common reference base is available for surveyors, designers, and contractors, back-and-forth confirmations can be reduced. In cultural property preservation, small differences in understanding can affect construction content or preservation policy. Making shape information easy to share directly supports high-precision consensus-building.

Difference from photography 4: Preservation management and expansion of future uses

Photographs are suitable for visually recording the current state, but three-dimensional recording by 3D laser scanners has the characteristic of a wide range of future uses. Cultural property preservation is not work that ends when a survey is completed. Maintenance, inspections, accumulation of repair histories, disaster response, public use, and research utilization mean that information will be used over a long time axis. Therefore, how useful the records obtained now will be in the future is important.

With three-dimensional data, when new issues appear later, it is easier to trace back and check past shapes. For example, if displacement becomes a problem years later, past three-dimensional records can help determine whether signs were already present and where change began. Photographs alone can be helpful but lack strong backing for dimensions and cross sections, limiting the scope of analysis.

Cultural property protection also connects to education, research, exhibition, and disaster prevention. If three-dimensional data are maintained, it is easier to inspect shapes non-contact, share them remotely, or use them as references for future reconstruction or restoration. The less frequently an object can be handled, the greater the value of accurate digital shape records.

Furthermore, cultural property management requires understanding relationships with the surroundings, not just individual objects. It is necessary to capture spatial context including buildings and ground, stone walls and slopes, ruins and surrounding topography, and structures and circulation routes. Photographs excel at cropping targets but are not easy for quantitatively organizing relationships with surroundings. Three-dimensional records help both the precision of single objects and spatial understanding including the surroundings.

In other words, if photographs preserve how something looks now, 3D laser scanners tend to become the foundation for passing the current shape on to the future. In fields like cultural property preservation where information is used across time, this difference is significant.

Additionally, future uses do not always proceed as originally planned. Data collected as baseline materials for repairs may later be needed for exhibition description, academic study, disaster training, or surrounding area planning. In such cases, if three-dimensional data remain, they are easier to reuse from a new perspective. In cultural property preservation, the goal is not to use records once and discard them, but to turn them into assets that can be used over the long term.

Situations where 3D laser scanners are particularly powerful

3D laser scanners are effective for many cultural properties, but there are situations where they provide especially strong benefits. First, when shapes are complex and photographic methods alone make spatial understanding difficult. Examples include stone walls with fine undulations, wooden buildings with complex assemblies, sculptures with many reliefs, and ruins integrated with topography—these have high value for three-dimensional recording.

Second, when you want to compare deformations or deterioration. If you want to track the progression of tilt, settlement, bulging, loss, or displacement, three-dimensional comparison is highly meaningful. Photographs can indicate signs of abnormality, but for preservation decision-making it is stronger to be able to explain with positions and quantities.

Third, when site conditions are difficult and re-surveys are hard. Before-and-after disassembly repairs, short periods with scaffolding, immediately after disasters, or areas with access restrictions are cases where you want to capture information reliably in a single operation. The advantage is that if another cross section becomes necessary later, it can be examined from the acquired data.

Fourth, when there are many stakeholders and a high degree of accountability. Cultural property preservation involves explaining situations not only to specialists but also to owners, local stakeholders, and administrative officials. In such cases, three-dimensional records complement spatial information that photographs alone cannot convey. With a shared foundation for understanding, the quality of discussions improves.

Conversely, if the target is relatively simple and the main objective is surface appearance rather than shape understanding, and there is no plan for future drawing or comparison, photograph-centered records may be sufficient. The important thing is not to introduce a 3D laser scanner as an end in itself. In cultural property preservation, choosing the right method at the right time based on the nature of the object, preservation issues, and future use yields the best results.

Practical precautions to keep in mind when introducing them

Even if 3D laser scanners are effective, simply measuring is not enough to produce outcomes. To turn introduction into results in cultural property preservation, several perspectives should be addressed before implementation.

First and foremost, clarify the purpose of the recording. Whether the goal is preserving the current state, obtaining baseline materials for repair design, anticipating temporal comparison, or considering public use affects the required acquisition range, accuracy, and processing content. Proceeding with an ambiguous purpose can result in a large volume of data that is difficult to use later.

Next, decide in advance the role-sharing with photography. Use photographs to complement color, texture, appearance of details, record shots, and explanatory images, and let three-dimensional methods support shape, dimensions, comparison, and drawing—organizing by purpose makes on-site work smoother. Relying too heavily on either photographs or three-dimensional data can result in missing necessary information.

Furthermore, consider post-acquisition organization and operation. In cultural property preservation, how obtained data are stored, retrieved, shared, and used in the future is more important than measurement itself. If you do not plan file management, coordinate handling of coordinates, link records to ledgers, or set standards for comparison, valuable three-dimensional data can get buried.

Also, depending on the nature of the object, plan for details that are prone to shadows or occlusions and confined spaces. Cultural properties often have complex shapes that create blind spots. By organizing in advance what to target and to what extent to capture, you can reduce the risk of discovering insufficiencies later.

Another often overlooked point is reproducibility of records. For future comparisons, standardizing the acquisition range, reference positions, and management methods is important. Even if you obtain high accuracy in the first session, if subsequent records cannot be linked, the value of continuous comparison decreases. Cultural property preservation is a long-term endeavor; therefore, design for continued use rather than one-off data acquisition is required.

Improving accuracy in cultural property preservation also requires organizing site positional information

We can confidently say that 3D laser scanners are effective for cultural property preservation. They produce values that photographs cannot provide, especially when you want to preserve shapes objectively, compare temporal changes, connect to drawing and measurement, and utilize the data for future maintenance. At the same time, photographs remain important for recording color, texture, surface condition, and intuitively sharing site conditions. In practice, combining photography and 3D laser scanning according to recording purposes is most effective, rather than setting them against each other.

What is truly required in cultural property preservation is not only creating attractive records. It is turning records into assets: being able to review them later, compare them, explain them to stakeholders, and use them immediately when needed. 3D laser scanners are a highly effective means to build that foundation. By leveraging the roles that photographs play while strengthening shape records and positional reference standards, practical cultural property preservation becomes more reliable.

To make three-dimensional records of cultural properties truly usable assets, it is also important not only to preserve shapes but to organize where the data were acquired as positional information. Considering relationships with surrounding terrain and structures, correspondence with past records, and ease of rechecking on site, the more consistent the positional references, the more stable subsequent operations become. If you want to proceed with cultural property recording and simple surveying more efficiently on site, using an LRTK—an iPhone-mounted GNSS high-precision positioning device—makes it easier to add high-precision positional information to photographs and site records. When three-dimensional records, photographic records, and positional information can be managed together, cultural property preservation shifts from mere recording work to building an information foundation that will be useful in the future.