Laser scanning technology helps preserve and repurpose a historic masonry building in Crete

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Laser scanning technology helps preserve and repurpose a historic masonry building in Crete

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Postgraduate students at the Technical University of Crete used a combination of a Trimble Laser Scanner, PointCab Origins Pro, and Autocad to obtain and document the exact geometry of a historic masonry structure with the purpose of its structural rehabilitation.

The island of Crete, Greece is known for its beautiful landscape and rich history. It’s the birthplace of the first European advanced civilization, the Minoans, and was shaped by the Mycenaeans, Romans, Osmans, and many more. The traces of these cultures can still be found all across the island in different archeological remains.

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One of them is a two-century-old residential masonry, built during the Osman rule. It has been abandoned for the last 70 years and is the former residence of the wealthy Seimeni family. As one of the few remaining buildings of that type of local architecture in the region, it bears great historic value. In order to preserve and repurpose the building, exact documentation of its geometry was required, among other factors, in order to assess its structural integrity and the degree of necessary strengthening interventions. The building is planned to be restored in the next years and to be used as a local folk art museum.

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Postgraduate student Eirini Chorianopoulou, supervised by Professors Maria Stavroulaki and Nikos Skoutelis decided to exploit the benefits of the latest laser scanning technology available. Since there were parts of the building that could not be approached and a distant measurement technique was needed, using simpler tools and techniques would not suffice. Therefore, an accurate digital representation of the building in its condition before the restoration could be captured. 

This will give future visitors the chance to understand and compare the prior and current state and appreciate the work that will be done in order to preserve the authenticity of the structure after its restoration. With the purpose to obtain the geometric properties of the structure, the Trimble X7 3D laser scanner was employed. A number of 25 scans were used to generate the point cloud. All the data was imported as e57 format files and edited in PointCab Origins Pro. Accurate plans, sections, and elevations of the structure were created at all necessary levels and were exported as .dwg files for further editing in Autocad. Postgraduate researcher Evangelos Nitadorakis, responsible for handling the point cloud evaluation, found himself satisfied with the results that the use of PointCab’s Origins software provided: 

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“The accuracy of the generated sections allowed the identification and quantification of pathology indicators such as wall inclinations not visible with the human eye and remote measurements in parts of the structure that are not easily accessible. In addition, the delta analysis tool helped to distinguish even the slightest deviations in vertical levels. Furthermore, with a proper combination of all the data from Origins, an exact 3D model of the structure was created in a FEM analysis software and structural and dynamic analysis were conducted in order to assess the fragility of the structure under various loading cases. Employing PointCab Origins, we appreciated the easy handling, the speed of data processing, and the quality of the outcomes.”

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What are point clouds?

Punktwolke point-cloud

Basics: What is a point cloud and how is it created?

A point cloud can best be explained with the help of a gadget that reached the peak of its popularity in the 00s and is now primarily used for presentations: the laser pointer. The laser pointer can be used to illuminate a precise point in a straight line. If you know exactly where the laser pointer is located in the room, you can also exactly locate the point that is being illuminated. After all, the laser beam is straight as a die and thus makes it possible to calculate the exact position of the point in space in relation to the origin (the laser pointer). Geodetic points in surveying are also measured according to this basic principle, only it’s a little more complex. Instead of a laser pointer, special tachymeters are used for this purpose. 

And what does this have to do with point clouds? Quite simple. In addition to total stations, laser scanners have been used more and more frequently for surveying in recent years. These also work in the same way as our laser pointer, except that they can measure thousands or even millions of points simultaneously. 

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Taken together, all the measured points constitue the point cloud. They contain an incredible amount of information because every single point in the point cloud has its own X, Y, and Z coordinates. If we scan a staircase with a laser scanner, for example, we can use the resulting point cloud to determine exactly how straight the individual steps are, where the steps are worn and how high the deviation from the construction standard is. Accordingly, laser scanners and the point clouds they produce are always used when you want to accurately document existing structures, for example to digitize, measure or modify them. 

What are point clouds used for?

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 For the design and optimization of production parts, for example in the automotive industry, very high-resolution hand-held scanners are usually used. They can capture even the smallest details and deviations. This allows a digital twin to be created on the PC. With the help of the twin, new prototypes can then be created and improvements digitally simulated and tested.

In the construction industry and as-built documentation of buildings, various scanners are used. Depending on the object, mostly terrestrial or mobile laser scanners, sometimes even drones. They are used to scan buildings for a variety of reasons, e.g. to plan an extension or renovation, to optimally position new equipment in production buildings, or to document the construction progress of various building projects. 

These are just a few examples of applications. Point clouds are used wherever objects need to be precisely captured and digitized. Depending on the area of application, different laser scanners are used. They can produce different accuracies and point cloud sizes. 

How to work with point clouds?

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How to work with point clouds depends above all on what goal you are pursuing. As already mentioned, different laser scanners are used for different areas of application. The same applies to the software used to evaluate the point clouds. Our software solution, Origins, for example, is mainly used when existing buildings or landscape structures are to be digitally captured.

Regardless of which hardware and software solutions are used, there is an important step between the acquisition and the evaluation of the point cloud data: the registration.

Point Cloud Registration

During registration, individual scans or individual “sections” that were captured with the laser scanner are merged into a point cloud. If you want to register a complete building, for example, you often set up the laser scanner in the different rooms and scan them. Of course, in the end, you don’t only want to have individual scans of the different rooms. You prefer simply one large point cloud in which all the scans are available and linked together. To achieve this, you have to register the scans.

Behind the registration usually stands a rather complicated mathematical process. The accuracy of the data produced by the registration depends on how well the laser scanner captured the environment on site and how reliable the registration software used is. 

 

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Fortunately, this process has become easier and easier in recent years. If you use a mobile laser scanner, for example, you often no longer have to make individual scans. You can simply walk through or around the object with the scanner. With this type of scanner, registration is also usually fully automatic and provided together with the hardware. The user does not need much know-how. The disadvantage here, however, is that mobile laser scanners are currently often not able to deliver as precise results as terrestrial laser scanners, i.e. scanners that are set up stationary and take individual scans one after the other.

There are different methods to register a point cloud. The best known are cloud-to-cloud registration, target-based registration, or plane-to-plane registration. Which method to use depends on many different factors, e.g. the laser scanner used, the desired accuracy, or your own preferences. Especially for newcomers, it is, therefore, advisable to have the scanning and registration carried out by experts. They not only register the point cloud but also “clean” it in most cases during the registration process. This means, for example, that duplicate scans or “noisy” areas of the point cloud are removed or the point cloud is professionally “thinned out” to reduce the file size.

Importing, processing, and passing on point cloud data

If you receive registered point cloud data, there is usually one more stumbling block to overcome before you can take measurements and create digital 3D models from the data – importing the data.

There is not just one file format for point clouds. In general, each laser scanner works with its own file format. Different software for processing are often using their own formats as well. As a result, there is hardly any software that can import all native file formats from the different laser scanners and processing software. We are very proud that our Origins (Pro) software can read and import over 25 different point cloud formats and export over 20 different formats (point cloud formats and others). However, even though we provide one of the greatest diversities on the market, it still doesn’t represent all native data formats. So what is the best way to deal with the different file formats?

Open exchange formats such as .las, .laz, .e57 or .xyz offer a solution to this problem. These file formats were developed by independent parties to solve the problem of data transfers. The .e57 format in particular has virtually become the industry standard. Almost all registration software of the laser scanner manufacturers can output the format and processing software for point clouds can also read the format. Therefore, in most cases, the surveyor will hand over the point cloud in .e57 format.

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The disadvantage here is that the .e57 format, in contrast to the native formats, is less well compressed. Therefore it requires more storage capacity in comparison. However, the large amounts of data are normally no problem for point cloud software. After all, they were developed specifically for the processing and evaluation of point clouds. They can be used to carry out measurements and other evaluations. With Origins for example, you can also create automatic floor plans that can be vectorized and much more

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However, if you want to create a 3D model from the point cloud, you need to employ a BIM or CAD software. These were not originally developed to handle point cloud data. Accordingly, many of these software still have major problems processing the data. Some CAD software, such as Autodesk Revit or AutoCAD, cannot read .e57 or other common point cloud formats. In order to use these software, the data must be converted again into the Autodesk formats .rcp or .rcs. Other CAD software cannot read point cloud data at all or can only import small amounts of data at once, which means that the point cloud has to be “split” again and imported in parts. These are all very tedious and time-consuming tasks.

To avoid this effort, the data is often first pre-processed in a point cloud software and then further processed in the CAD software. For example, Origins (Pro) can be used to create floor plans and vector lines, which can then be transferred to the CAD software in the correct position and with all the important 3D information in .dfx or .dwg format. These formats can be processed by almost any CAD software and require much less storage capacity than the entire point cloud. Of course, there are now also plugins for the most common CAD software that can transfer the 3D information from the point cloud software directly to the CAD software.

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In conclusion, it can be seen that the acquisition and processing of point clouds, right up to the creation of a 3D model, still requires a great deal of expertise and know-how. Especially the amount of data and the data exchange between the different systems is still a challenge. Fortunately, a lot has already been done in recent years to simplify this process, also known as scan-to-BIM. We are also working every day to be able to import more data formats into our software and to simplify the handling so that even beginners can work with point clouds.

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Surveying Dunelm House

dunelm house

Dunelm House: Why a Precise 3D Survey Was Needed

Dunelm House (1966) is Durham University’s well-known students’ union building. Designed in the post-war modernist style, it sits directly on the steep banks of the River Wear. Furthermore, it is connected to the equally iconic Kingsgate Bridge.

The structure is characterized by exposed concrete and terraced floor levels. A multi-angled, irregular roofscape follows the natural slope of the riverbank. This bold design makes Dunelm House architecturally significant  – and challenging to measure.
When leaks appeared across several roof areas, a detailed digital survey was needed. The aim was to document the current condition and guide the renovation.

The Challenge: Complex Roof and Difficult Site Conditions

The student building’s roof consists of intersecting levels, changing slopes, and unconventional angles. Combined with its sloping riverside location, this makes traditional measurement methods unreliable and slow.

To capture the structure accurately and efficiently, the project required a modern surveying approach capable of documenting every plane and surface with precision.

How the Survey Was Completed: Laser Scanning + GPS

The survey was carried out by Bury Associates Ltd using two FARO Focus3D laser scanners. To record the terrain and ensure accurate referencing across the entire site, the team also used total stations and GPS equipment.

This hybrid surveying method made it possible to capture:

  • the full exterior geometry of Dunelm House,
  • its complex multi-level roof structures,
  • and high-precision topographic context along the River Wear.

The result was a detailed point cloud covering the entire building and its surroundings.

We think PointCab Origins is the fastest way to extract plans and sections from point clouds.
Bury Associates Limited
Dez. 2018

From Point Cloud to 3D Model: Deliverables in Four Days

After the scanning process, the data was processed using PointCab Origins, which enabled the team to deliver complete documentation in just four days.
The deliverables included:

  • orthophotos,
  • 2D floor plans,
  • sections and elevations,
  • and a full 3D Revit model created from the processed Origins data.

By exporting PointCab’s results into Autodesk Revit, the project team gained a BIM-ready model with the accuracy needed to analyse the leaking roof and plan the renovation.

How the Digital Survey Supports the Renovation Process

The Dunelm House project shows how 3D laser scanning, precise site measurement, and point cloud processing can deliver fast, reliable results — even for buildings with complex shapes and challenging site conditions.

With the combination of FARO scanners, survey instruments, and PointCab Origins for evaluation, Bury Associates delivered a complete set of renovation-ready outputs, including a detailed Revit model.
This provided architects and engineers with a solid digital foundation for repairing and preserving one of Durham’s most distinctive architectural landmarks.

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As-built documentation of an old house

As-Built Documentation of an Old House: Why a Complete 3D Laser Scan Was Essential

An old residential building in a village in the Swiss canton of Ticino lacked reliable, up-to-date building plans. To prepare renovation and restoration work, the engineering firm Geomatica Righitto (Lugano, Switzerland) was commissioned to do a full 3D as-built documentation.

Traditional plans were missing or outdated, and the building required precise measurements to support planning in CAD and BIM software.

Missing Plans, Irregular Geometry, and the Need for Precision

Older buildings rarely follow perfectly straight lines or standardized geometries. Over decades – or even centuries – walls may shift, floors may sag, and angles deviate from 90 degrees.

This means: assumptions based on symmetry or “standard” geometry can be highly misleading.

For renovation work, especially structural or restorative interventions, accurate data is crucial. Because no reliable plans existed for this house and its geometry was visibly irregular, a precise and complete measurement was essential, making 3D laser scanning the ideal method.

Survey: Faro Photon 120, Faro Scene, and Efficient On-Site Work

Geomatica Righitto used a FARO Photon 120 laser scanner to capture the entire building, including:

  • three façades,
  • the basement,
  • the roof,
  • and all four floors.

In total:

  • 29 scans,
  • 6 hours on site,
  • 3 survey specialists.

All scans were registered and merged in FARO Scene, ensuring correct alignment and a unified, consistent point cloud.

This point cloud became the complete digital representation of the building, including all the irregularities typical of older structures.

Point clouds are for engineers, plans for architects. PointCab Origins is the fastest connection between them.
Marzio Righitto
Engineer - Pastorelli SA
Dez. 2018

Processing the Point Cloud: Fast Extraction of Plans and Sections

Once the unified point cloud was ready, Geomatica Righitto used PointCab Origins to extract essential architectural outputs:

  • 4 floor plans
  • 3 façade plans
  • 20 building sections
  • Orthophotos for façades and interior walls

These automated extractions significantly reduced manual drafting work.
The final drawings — both as-built documentation and renovation plans — were delivered in a CAD/BIM-ready format for use in Archicad.

The entire processing workflow, including preparation for delivery, took about 8 hours.

What This Case Study Demonstrates

This project shows how even older buildings with irregular geometry and missing documentation can be comprehensively captured. Old buildings are rarely dimensionally perfect, but laser scanning captures reality exactly as it is, and the resulting point cloud becomes a trusted digital baseline.

The combination of FARO Photon 120, FARO Scene, and PointCab Origins enabled Geomatica Righitto to create reliable plans quickly –  giving architects and engineers the confidence they need to design renovations and restoration work effectively.

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Surveying of 12.000sqm of inhabited floor space

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Surveying 12,000 m² of Inhabited Floor Space:
Why a Complete 3D As-Built Survey Was Needed

The project involved surveying more than 12,000 m² of inhabited floor space, including a hotel, a municipal theatre, offices and residential units.

For such mixed-use buildings, reliable and up-to-date as-built plans are essential — especially when fire-protection documentation is required.
Because existing plans were incomplete and the building was in active daily use, a full digital survey became the most efficient and accurate solution.

The Challenge: Surveying a Large, Inhabited Mixed-Use Building

Inhabited buildings present extra challenges compared to empty or unused structures:

  • Continuous operation: Hotel guests, office staff and residents could not be disturbed.
  • Mixed layouts: Hotels, theatres, offices and residential spaces each have different room structures, escape routes and technical areas.
  • Complex circulation: Theatre back-of-house zones, technical rooms and varying ceiling heights complicate manual measurement.
  • Large total area: Over 12,000 m² had to be captured consistently across several building sections and levels.

To meet these challenges, the team selected a high-precision, fast and non-intrusive method: 3D laser scanning.

How the Survey Was Completed: FAST Laser Scanning With Only Two People

The surveying was executed by Faschang Service & Management GmbH, who used a FARO Focus3D laser scanner to capture every part of the building.
Despite the size and complexity, the entire scanning process was completed:

  • in 45 hours,
  • using just two employees.

This shows the efficiency of laser scanning in inhabited environments: the scanner captures geometry quickly, quietly and with minimal disruption to regular building operations.

Point Cloud Evaluation in PointCab Origins: From Scan to Plans

Once the point cloud was created, it was processed in PointCab Origins, where essential deliverables were generated automatically:

  • floor plans,
  • site plans
  • sections
  • orthophotos.

Using these true-to-scale orthophotos, the team produced the required as-built drawings and fire-protection plans in AutoCAD.

Because all data originated from the point cloud, the resulting plans were consistent, accurate and based on the current state of the entire 12,000 m² complex.

The perfect software solution for efficient creation of orthophotos and as-built plans.
Faschang Service & Management GmbH
Jun. 2013

Digital Data for Future Use: One Scan, Many Applications

A major advantage of the workflow is that the complete point cloud was stored as a digital record.
This proved useful later: when façade drawings were needed for extension planning, the team was able to generate them directly from the existing scan — without additional site visits.
One scan created a long-term data resource that can support fire protection, renovation, design updates or further documentation tasks.

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