How to Preserve Cultural Heritage in 3D with iPhone LiDAR | Costs and 7 Things to Watch Out For

In recording and preserving cultural properties, it is important to keep an accurate record of the current condition and manage it in a way that can be utilized for future investigation, restoration, and comparative verification. In recent years, iPhone LiDAR has attracted attention as on-site equipment that is easy to handle, drawing interest from practitioners who want to acquire three-dimensional data more easily than before. That said, cultural properties are objects that cannot be restored once damaged, and if adoption is pursued solely because it is convenient, it may fail to achieve the required accuracy or produce data that is difficult to use in subsequent processes.

In this article, from a practical perspective, we organize and explain the basics of using iPhone LiDAR to 3D-preserve cultural heritage, how to proceed on-site, the factors that influence costs, and the precautions to be aware of before implementation. Finally, we also touch on using LRTK as a way to further ensure management of cultural heritage location information and verification of on-site coordinates.

Table of Contents

• Reasons iPhone LiDAR is attracting attention in the cultural heritage field

• What can be done with 3D preservation of cultural heritage

• Basic Steps for 3D Preservation of Cultural Heritage Using iPhone LiDAR

• Main factors that affect costs

• Note 1: Do not make accuracy targets ambiguous

• Note 2 Understand losses due to material and shape

• Point 3 Do not overlook the outdoor environment and surrounding conditions

• Point 4: Do not neglect organizing and naming after acquisition

• Note 5: Choose a recording format with long-term preservation in mind

• Note 6: Be mindful of sharing with stakeholders and reuse

• Note 7: Ensure the accuracy of location information separately

• The significance of combining LRTK in practical work for cultural heritage

• Summary

Why iPhone LiDAR Is Gaining Attention in the Field of Cultural Heritage

In surveys and conservation of cultural heritage, there are many situations where you want to capture an object's shape without touching it. The ability to preserve in three dimensions information that is easily overlooked by the naked eye—such as the weathering state of stone objects, deformation of wooden components, undulations of archaeological remains, irregularities on wall surfaces, and differences before and after restoration—is a major value of 3D recording. Traditionally, specialized equipment or outsourcing has often been assumed, making it difficult in terms of preparation and effort to immediately record points of concern on site.

In that regard, iPhone LiDAR's strength is that it allows you to start acquiring three-dimensional information with a device that is easy to carry daily. Because recording work can be entered into as an extension of on-site inspections, the initial response is quick and trial implementation is easy. In the cultural heritage field, rather than measuring everything on a large scale, it is easy to imagine introducing it first for uses such as preserving the current condition, comparative recording, routine inspections, and creating materials for repair planning, and iPhone LiDAR is a well-suited means as that entry point.

Also, in the practice of cultural heritage work, the frequency of recording is important. Even if large-scale surveys are conducted once a year, many sites want more frequent routine checks. If there is an easy way to create three-dimensional records, it becomes much easier to begin recording immediately when an anomaly is discovered and to lay the groundwork for later comparison with detailed investigations. In other words, the value of iPhone LiDAR lies less in completely replacing expensive specialist equipment and more in increasing recording opportunities and making it easier to incorporate three-dimensional preservation into everyday work.

However, the quality of documentation required for cultural properties varies from case to case. Whether it is for a preservation register, for restoration design, or for education and outreach will change the required resolution, the precision of coordinates, and the extent of post-processing. Therefore, before implementation you must clarify "what the record is being kept for"; otherwise, there is a risk that convenience alone will take precedence, so caution is necessary.

What 3D Preservation of Cultural Heritage Can Do

3D preservation of cultural properties using iPhone LiDAR is not merely intended to create a three-dimensional appearance. What matters in practice is whether it can serve as a record that can be reviewed later. For example, for stone monuments, stone Buddhas, grave towers, exposed surfaces of archaeological features, parts of historic buildings, on-site arrangements before storage, and the topographical relationships at excavation sites, depth and tilt information that are difficult to capture with photographs alone can be important. If digitized in three dimensions, a different staff member can more easily understand the shape later without needing to revisit the site.

Furthermore, 3D preservation of cultural heritage plays a major role in enabling comparisons. When tracking weathering, damage, subsidence, tilting, surface delamination, and other changes over time, being able to compare past data with current data is extremely useful. Even if acquiring data under exactly the same conditions each time is difficult, continuously recording according to a consistent set of rules makes it easier to detect signs of change early. This is helpful not only for conservation management but also for determining repair priorities.

They are also well suited for sharing among stakeholders. The preservation of cultural properties often involves multiple roles, such as investigators, managers, construction personnel, designers, and administrative officials. Shapes that are hard to convey with only two-dimensional photographs can be more easily understood when three-dimensional data is available, which helps create a shared understanding and improves the quality of meetings. Because it becomes easier to share the situation with stakeholders who cannot visit the site, it also leads to faster decision-making.

Three-dimensional records also have value from the perspectives of education and archiving. Beyond preservation, they can be used in public facilities and interpretive materials, for future exhibition planning, and as documentation for disaster recovery. However, the broader the intended uses, the more important it is to be mindful of data integrity and storage rules during the acquisition stage. This is because data collected initially for on-site recording are often wanted for other purposes later.

Basic steps for 3D preservation of cultural heritage using iPhone LiDAR

When preserving cultural heritage in 3D with iPhone LiDAR, it is important not to start shooting on a whim but to design the entire workflow as a continuous process from preliminary checks through organization. The first thing to do is to understand the subject. How much to include in the recording range, whether close-range capture is sufficient, and whether to include the surrounding topography and spatial relationships will affect how you walk, the acquisition time, and the amount of data required. You should decide at the outset whether you want to preserve only the cultural asset itself or also its relationship with the surroundings.

Next, confirm the site conditions. Outdoors, factors such as direct sunlight, shadows, wetness after rain, swaying vegetation, and the safety of footing or scaffolding can affect the work. Indoors, check for narrowness, darkness, movement/ circulation routes, distance to exhibits, and access restrictions. For cultural properties, since touching the object is prohibited, plan movement routes so that you do not bring the device close in awkward postures or photograph from unstable positions.

During acquisition, move around the object at a steady speed while collecting data with sufficient overlap. If you suddenly swing the device or capture from widely spaced positions, continuity will suffer and the shape may become distorted later. Even if you capture the front neatly, if the sides, back, and the contact with the pedestal are insufficient, the dataset will be difficult to use as a whole. Because cultural properties often have complex shading and fine details, it is important to proceed while confirming on site that each surface has been captured.

After acquisition, perform cleanup of unwanted parts and check for missing data. If people, vehicles, temporary structures, or moved vegetation are included, you may need to clean them up depending on the intended use. Also, depending on the purpose of storage, linking the three-dimensional data with photographic records and on-site notes will make later reuse easier. This is because standalone three-dimensional data tends to become ambiguous as to when, where, and for what purpose it was acquired.

Finally, perform file management. In cultural heritage recording, it is extremely important that items can be found later. If you do not manage object names, site names, acquisition dates, collectors, scope, versions, etc., according to a consistent set of rules, the data you worked hard to collect will become buried. The ease of capturing data and the ease of operating a system are separate issues. Precisely because data can be captured easily, you need to decide on organization rules from the outset.

Main factors that affect cost

When using iPhone LiDAR for 3D preservation of cultural heritage, it's important to understand what affects costs rather than the price itself. In the cultural heritage field there is a large variation between projects, and a simple, one-size-fits-all comparison makes it hard to grasp the actual situation.

First, the biggest factor is the scale of the subject. Whether you record a single small stone object, document an entire archaeological feature, or capture a large portion of a structure, both on-site work time and post-processing time change significantly. The larger the subject, the more time-consuming it becomes to check for missed areas and to integrate the data.

Next is the required accuracy. For documenting current conditions and sharing, a relatively light workflow can suffice, but if restoration planning, shape comparison, or integration with coordinate management is required, supplementary positioning and the establishment of reference points become necessary. Because this increases the amount of work, the way costs are considered also changes. For cultural heritage, not only visual reproduction but also the reliability of location and dimensions may be scrutinized, so setting accuracy according to the intended purpose is important.

Furthermore, on-site conditions cannot be ignored. Conditions such as unstable footing, access restrictions, confined surroundings, the need to accommodate visitors, and time-of-day constraints directly affect work efficiency. Cultural properties require more considerations than ordinary survey targets, and it can be difficult to estimate the time needed for the work. Because ensuring safety and consideration for the surroundings take priority, matters cannot be decided solely on the basis of efficiency.

The depth of post-processing is also a major factor. The amount of work required varies depending on whether you merely preserve the data, remove unwanted elements, organize it into a form that is easy to compare, or prepare it for use in reporting materials. In cultural heritage archives, organization that anticipates future reinterpretation and reuse is required, so the effort of organizing and managing the material can sometimes be greater than the time spent acquiring it on site.

An often-overlooked factor is the cost of revisits. If deficiencies are discovered during the initial acquisition, you may need to return to the site. Cultural properties cannot always be re-acquired at will; permissions and schedule adjustments may be required. Therefore, clearly defining the acquisition objectives and the items to be checked at the earliest stage will ultimately help reduce costs.

Please provide the Japanese text you would like me to translate.

One of the most common mistakes when using iPhone LiDAR for cultural heritage is starting from the vague premise that it's fine as long as you can somehow create a 3D model. In cultural heritage documentation, being usable for practical work later takes precedence over appearance. Whether the goal is to capture the current condition, to verify dimensions, to compare before and after restoration, or to produce material for future reconstruction greatly changes how you should think about the required level of accuracy.

For example, when used as a three-dimensional reference for explanation, ease of understanding the overall shape may be prioritized over minor inaccuracies. On the other hand, if you want to track areas of damage or check displacements, reproducibility of acquisition conditions and positioning becomes important. Even within "3D preservation of cultural heritage," the standards required differ depending on the intended use.

If you proceed with this unclear, even if you believe you collected enough on site, problems can later arise such as "this data can't be compared," "it's hard to use as a metric," or "the locations are ambiguous and difficult to include in records." Therefore, before starting you should at minimum confirm which units you want to use, which range you want to compare, and how accurate the positions need to be.

For cultural properties, the clearer the purpose of each project, the more appropriately the acquisition method can be decided. Conversely, if the purpose remains vague, even methods that appear convenient are likely to diverge from expectations. When introducing iPhone LiDAR, the starting point is to first articulate and share the accuracy targets.

Note 2: Understand misses caused by material and shape

Cultural properties vary widely in both material and form. Stone, wood, earthen materials, metal, plaster, tiles, and the like each have different surface conditions. Moreover, weathering, loss, cracks, chips, surface irregularities, and fine decorative details often contain the information that needs to be recorded. For this reason, if they are treated with the same mindset used for general spatial measurement, important details are easily overlooked.

For example, fine linear patterns, deep carvings, sharp edges, and intricate gaps can become difficult to capture depending on the viewing angle and distance. While it may be easy to capture the continuity of shape on areas that appear uniform, deficiencies tend to occur in complex fine details. In addition, depending on the surface condition, something that appears to have been recorded sufficiently may, when magnified later, be overly smoothed and have lost the necessary features.

For cultural properties, chips and wear themselves constitute important information. Therefore, rather than simply doing a once‑over of the whole object, it is necessary to identify important areas in advance and adopt a stance of focusing inspection on those parts. Surfaces bearing inscriptions, corners where damage has progressed, joints with repair histories, and interfaces with the foundation—locations that are likely to be reviewed later—should be thoroughly checked on site.

Additionally, the relationship with the surroundings—not just the object itself—may be necessary. Even if the form of the cultural property can be captured, without understanding its installation orientation, inclination, ground contact, or its relationship to surrounding drainage and vegetation, there will be insufficient information for conservation management decisions. It is important to understand the complexity of materials and forms and to acquire data with attention to both priority areas and surrounding conditions.

Important point 3: Don't overlook the outdoor environment and surrounding conditions

Cultural heritage sites are not always environments that are easy to measure. At outdoor historic sites, stone structures, ruins, and features within gardens, there are many disturbances such as sunlight, shadows, wind, humidity, mud splashes, fallen leaves, overgrown vegetation, and foot traffic. These affect not only the quality of documentation but also safety and work efficiency.

What's especially important is to keep the acquisition conditions as consistent as possible. If you plan to compare with past data, captures made in bright midday sun and in a cloudy evening can look completely different, making comparison difficult. Of course field conditions are influenced by the weather, but at minimum, by noting the time of day, the weather, and the surrounding conditions each time you record, later interpretation becomes easier.

Also, because there are often access restrictions and protective measures around cultural properties, you cannot act based solely on ease of measurement. If you ignore conditions such as being unable to approach the subject, being able to view it only from certain directions, unstable footing, or overlap with visitor flow, you will end up attempting impractical acquisitions, and as a result the data quality will deteriorate. Safety and protection considerations must be given top priority, and you should think about how to maximize what can be captured within those constraints.

Furthermore, attention must be paid to the effects of temporary structures and surrounding objects. If construction materials, protective coverings, signs, fences, information boards, visitors, or the like are present, additional sorting may be required later. Cultural properties are subject to strong site-specific constraints, so rather than aiming for perfection on the day of acquisition, it is important to identify what is permanent and what is temporary and to record them with the intent of creating a usable record.

Point 4: Don't neglect organizing and naming after acquisition

One area where surprisingly large differences appear in the management of 3D data is post-acquisition organization. In the field of cultural heritage, there are often multiple objects, recordings span multiple shooting dates, and personnel may change. If the data naming conventions are ambiguous in such situations, it can take a long time just to find the intended record later. Even if data are carefully archived, data that cannot be located are difficult to use in practice.

For example, the name of a cultural property alone may be insufficient. When multiple targets exist within the same site, it is necessary to include the location, component, orientation, acquisition date, and acquirer according to consistent rules. If comparing before-and-after repairs, organizing the data chronologically is also indispensable. In preservation management spanning multiple years, consistency of rules can affect the asset’s value.

It is also important to link three-dimensional data not only by itself but with photographs, notes, location information, and on-site observations. Even if, on site, you know “there was a small chip here” or “this part was more discolored than last time,” you may not be able to judge that later from the data alone. Cultural heritage records become truly useful only when they preserve not just the form but also the context.

Post-acquisition organization is a mundane task, but it has a major impact on reusability. Especially for data accumulated over long periods, such as cultural properties, it is important to aim for organization that remains understandable even if the person in charge changes years later. To preserve ease of use in the field, the rules for organization should be established from the outset.

Please translate the following input into English.

Point 5: Choose a recording format with long-term preservation in mind

Three-dimensional data of cultural heritage is not something that is simply checked on-site and then finished. It may be revisited years later, or even further into the future. Therefore, it is important not to decide storage formats and management methods based solely on short-term convenience. Being able to open a file now is not the same as being able to read it in the future.

In the cultural heritage field, responsible departments and external collaborators may change, and data that is highly dependent on a specific environment tends to become an obstacle to reuse. Therefore, record formats should be chosen with future transfer and reinterpretation in mind. Not only visual clarity, but also the intended uses—dimension checking, location verification, comparative validation, preparation of explanatory materials, and so on—will affect which storage method is appropriate.

Also, the practice of storing the original (raw) data separately from the processed data is useful. It is not uncommon to want to change processing methods later. If only the cleaned data are retained, it can become difficult to repurpose the data for other uses. Because records of cultural properties have value not only for single-year reports but also for future reanalysis, management that is mindful of the records' authenticity is important.

Furthermore, long-term preservation requires the establishment and maintenance of a record ledger. If it is not clear when, who, where, what, to what extent, and for what purpose the data were acquired, the standalone value of the data decreases. In the three-dimensional preservation of cultural heritage, the practical key is not the data format itself but the organization of the accompanying information that explains the data.

Please translate the following input into English.

Note 6: Be mindful of sharing with stakeholders and reuse

3D preservation of cultural heritage is not something that only the person who acquired it should be able to use. It may be referred to by others in many situations—such as preservation management, repair planning, report preparation, explanatory materials, and future handovers. Therefore, it is important to keep in mind from the start to make it easy to share.

Even records that appear obvious to one person in charge may leave another unsure which parts are important. If orientation, the scope, damage locations, points of interest, and differences from the previous record can be checked together with three-dimensional data, the quality of information transfer changes dramatically. Because continuity of staff is not necessarily guaranteed in cultural heritage, it is necessary to devise ways to make the records themselves self-explanatory.

Also, the granularity of data affects reuse. Lightweight records for site rounds and detailed records for restoration review require different levels of depth. Standardizing everything as heavy data makes it cumbersome to handle, while making it too light makes it impossible to use for crucial decisions. It is important to design shared units with awareness of who needs the information, for what purpose, and to what extent.

Because the conservation of cultural properties cannot be completed with a single measurement, it is precisely for that reason that there is value in preserving them in a state that can be reused later. If sharing and reuse are anticipated at the time of the initial acquisition, this will more readily lead to subsequent surveys or consideration of other matters.

Note 7 Ensure the accuracy of location information separately

When using an iPhone LiDAR to preserve cultural heritage in three dimensions, attention tends to focus on recording shape, but in practice the surprisingly important factor is location information. In cultural heritage preservation, if where the data were acquired is ambiguous, it becomes difficult to compare with past data, re-check on site, or reconcile with registers. This is especially true for outdoor historic sites or when multiple targets are within a site, where the certainty of location greatly affects operational usability.

For example, if it is unclear which specific stone in a group of stone monuments was recorded, which face of the base was captured, or from which orientation it was recorded, it will cause confusion in the next survey. Even if the three-dimensional shape is preserved, if its correspondence with the site is unclear, it becomes difficult to use in the practical work of preservation management. Because cultural properties often derive their value from their local context, location information cannot be neglected.

Also, when you want to examine the relationship with surrounding terrain and structures, shape alone is insufficient. Only when the location, the area recorded, and the direction from which it was captured are organized does it become easier to compare with previous years and reproduce conditions on site. If positional information is solid, it is also easier to link the data with photographic records and inspection records, improving the overall consistency of the documentation.

For this reason, in three-dimensional preservation of cultural heritage, it is effective to combine shape acquisition by LiDAR with position verification by other means. In particular, for projects that require confirmation of on-site coordinates, identification of reference/control points, and clarification of recording locations, having a system to reinforce positional accuracy stabilizes subsequent processes.

The Significance of Combining LRTK in Cultural Heritage Practice

For stable, practical field operation of 3D preservation of cultural heritage, combining geometry capture using iPhone LiDAR with high-precision position verification using LRTK is highly effective. In documenting cultural heritage, it is important not only to capture the object's shape but also to clearly record where it is located. LRTK is a high-precision positioning device that can be attached to an iPhone, and it has features that make on-site position checks and coordinate handling easy to streamline.

For example, when sequentially recording multiple subjects within a historic site, it becomes easier to organize with high precision which subject at which point was captured. If stone monuments, archaeological features, component parts, and areas targeted for repair can be managed with location information, revisiting during the next survey becomes easier and a foundation for comparisons with previous years is established. Being able to link photographic records and three-dimensional data to their on-site locations has great significance in the practical work of cultural property management.

Even when you need to carry out simple surveying around cultural properties or verify control points on your own, LRTK is a well-suited approach. While grasping the extent of the site and the spatial relationships with surrounding facilities, it makes it easier to expand the range of uses for geometry data acquired with iPhone LiDAR. Of course, not every project requires the same level of accuracy, but separating shape recording from positional recording is important for making 3D preservation of cultural properties usable in everyday professional practice.

Even in situations where relying on an iPhone LiDAR alone makes handling position uncertain, combining it with LRTK makes it easier to verify on-site coordinates and clarify recording locations. If you want to develop cultural heritage preservation records into data that can be used for ongoing management rather than leaving them as mere visualization, LRTK is a reassuring option.

Summary

iPhone LiDAR is an excellent tool for 3D preservation of cultural heritage, offering ease of on-site deployment and immediacy of recording. In particular, it has significant practical value for tasks such as condition assessment, patrol recording, creating comparison archives, and establishing a foundation for stakeholder sharing. On the other hand, because cultural heritage cannot be easily re-recorded and each object is of high significance, it is dangerous to decide on adoption based solely on convenience. Considering accuracy targets, the characteristics of materials and shapes, site conditions, post-acquisition processing, long-term preservation, sharing methods, and securing positional information will lead to successful operation.

And to make 3D preservation of cultural properties more practical, it is important to consider separately the mechanisms for capturing shape and for securing position. If the current state can be recorded three-dimensionally with an iPhone LiDAR and on-site positioning and coordinate verification can be streamlined with LRTK, cultural property records will shift from mere preservation data to information usable for continuous management and decision-making. If you want to operate positioned three-dimensional records more reliably in cultural property surveys and preservation work, it is well worth considering a field recording workflow that combines LRTK.