Modern problems require modern solutions: how digital scans can aid heritage preservation

How can 3D scans assist heritage preservation? Images: SzabolcsHorvath (left), CyArk (right & centre) - Wikimedia. (All parts CC).

In uncertain times, such as war or natural disasters, preserving heritage is not always a priority. However, 3D scans of (not yet) endangered structures could be a new way to assist the digital preservation of heritage. Many initiatives in Europe are already exploring the possibilities. But can 3D models also go beyond a digital recreation and help real-life reconstructions?

The question seems more relevant than ever, as concerning reports from Italy keep coming in. Residents in and around Naples face earthquakes and a so-called ‘super volcano’, which would also affect the large amounts of cultural heritage present in the area.

It is definitely not the first time residents of Naples have had to deal with quakes and volcanoes. The ancient Greeks, who also inhabited the region, called the area just west of Naples the ‘Campi Flegrei’, or burning fields. Below the surface exists a network of underground volcanoes.

While the safety of residents should rightfully be at the top of the list, the safety of built heritage should be considered as well. The Naples area is one of the world’s oldest continuously inhabited regions. However, making every building, ruin, castle, or statue earthquake proof seems like an impossible job. Are these buildings doomed to be lost when disaster strikes?

Sulfur and gas escaping from the active Campi Flegrei in 20213. Image: Norbert Nagel/Wikimedia Commons (CC BY-SA 3.0)

3D scan?

A way to keeping these buildings ‘alive’ even after they are destroyed, could be through creating 3D models of structures. That way we can keep them safe in a digital realm, even when they get damaged or destroyed in the real world. How does that work?

First, you need a so-called 3D scanner: a special camera that doesn’t take regular pictures, but instead, it captures millions of tiny dots in 3D space. The scanner uses either laser beams or light to measure the distance from the scanner to different points on the building’s surface. To scan the entire building, a person would typically walk around it, or they might place the scanner in different positions. As they do this, the scanner sends out laser beams or light to bounce off the building’s surfaces.

When the laser or light hits the building, it bounces back to the scanner. The scanner measures how long it takes for the light to return, and this helps it calculate the distance to that point on the building. This process is repeated many times per second, creating many measurements. These measurements are like a cloud of points that represent the building’s shape and details.

All these collected points are used to create a 3D model of the building. Imagine connecting the dots to form a virtual version of the heritage building. Some 3D scanners can also capture the colour and texture of the building’s surface, like the paint or the patterns in the stone. This helps make the 3D model look realistic. To make the 3D model accurate and useful, special software is used to clean up the data, remove any errors, and create a smooth, detailed model.

European initiative

Many in heritage are already taking steps to see how we can digitalise (heritage) structures. A well-known example is the so-called Twin it! Campaign, run by Europeana Initiative. The goal of the project is to ‘collect and showcase emblematic and high-quality samples of Europe’s cultural assets in 3D.’ The project is a concrete answer to the European Commission Recommendation of 2021, which highlights the importance of a common European data space for heritage.

By 2030, European member states are encouraged to ‘digitise in 3D all monuments and sites deemed at risk, 50% of the most physically visited cultural and heritage monuments, buildings and sites, and pay special attention to specific categories of heritage assets with low level of digitisation.’

Apart from documenting European heritage structures in 3D models, the goal of the campaign is to showcase why it matters to map these buildings in the digital cloud. Europeana argues 3D models can broaden the access to culture, reaching larger and more diverse audiences. By making digital reproductions, professionals can learn more about how it is built and how to conserve or restore it in the future. And having 3D models of diverse heritage could lead to a boost in educating people about heritage, and the tourism industry.

Race against time

Twin it! Is certainly a step in the right direction, but what happens when mapping heritage becomes a race against time? A Ukrainian project shows how 3D modelling of heritage buildings can be done in times of conflict, when there is little attention for the potential loss of heritage.

When Lviv-based architect Julian Chaplinskyy saw bombs hail down on Kyiv and Kharkiv, he teamed up with a local firm Skeiron. Together they attempt to 3D scans of iconic landmarks in Ukraine by using lasers, Euronews reported. At the time of writing, they have recorded and mapped sixty structures in Ukraine.

Mapping Notre Dame

However, mapping and digitally preserving a 3D model of cultural heritage is one thing. Using such a model – or rather the data measurements upon which the models is created – to completely rebuild is easier than done.

Nonetheless, it is not impossible. The quick reconstruction of the Notre Dame in Paris has shown this. After the world-famous cathedral burst into flames in 2019, experts were wondering how they would rebuild the damaged parts of the church. Luckily, in 2001 architectural historian Andrew Tallon had made extensive 3D maps of the church. Tallon – who sadly passed away in 2018 due to brain cancer – set up a tripod in fifty different locations within the cathedral to scan and gather various digital points using lasers to map and measure. 

View Tallon’s digital scanning process of the Washington Cathedral in 2015.

More than two decades later the 3D models proved invaluable to the Notre Dame’s speedy reconstruction. Because even though the French state might have had architectural drawings or maps lying around, that’s often not how the building in practice would have looked like.

Tallon captured the cathedral as it was on the days that he scanned it, back in 2010. The 3D scans reveals that the structure has changed over time due to internal and external forces, down to one-millimetre accuracy. The data obtained by laser scanners offers far more precise measurements than any drawing, modern or historical, ever could.

There is only problem with these kind of extensive 3D scans, which consist of millions of measurement points. The scan are simply too big to store in a digital cloud. An article in The Atlantic reckoned the high-quality scans would be around one tera byte of data. Small enough to fit on an external hard drive. So even when you might have an impressive digital reconstruction of a building, you need to keep the physical storage location safe.

Scan while you can

Back to Italy, where the Campi Flegrei continue to rumble. As mentioned before, the safety of people should be the number one priority. However, heritage is often forgotten when disaster strikes. In the case of Ukraine, we see that sometimes preserving heritage in a digital manner can become a race against time.

With the modern technologies available to us, a plan to make 3D scans of the most important landmarks for future reference does not seem like a bad idea. So, let’s scan heritage in and around Naples. Who knows when we will need it next?