3D scanning and shape analysis help archaeologists connect objects across space and time to recover their lost histories

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Carlo Rindi Nuzzolo, University of California, Los Angeles

(THE CONVERSATION) Today the world of Egyptology faces a silent crisis – not of looting, although that plays a part, but of disconnection. Walk into any major museum, from Copenhagen to California, and you see glass cases filled with what could be called orphaned artifacts: remarkable objects, often acquired in the 19th and early 20th century, that have been completely stripped of their histories. You can see what they are – a mummy’s painted foot case, a golden mask – but we have no idea where they came from. They are beautiful, but historically they are mute.

Many objects entered museum collections at times when excavation and collecting practices were very different from today. In the past, excavated objects were often divided between institutions around the world, and display was prioritized over documentation. Over time, connections between pieces were lost. As a result, museums around the world hold remarkable artifacts whose backstories are thin, fragmentary or missing altogether.

Archaeologists like me working in the field today regularly uncover fragments: broken pieces of objects that once formed part of something larger. In some cases, those fragments may share the same underlying geometry with objects already held in museums. For example, a mummy’s foot case and a newly found shard may have been produced using the same mold, so they share a consistent three-dimensional form even if they are now separated by time, distance and absence of documentation.

Traditionally, evaluating whether a fragment matches up with a specific museum object has relied on visual judgment and incomplete records, rather than a quantitative comparison of shape.

This gap between excavation archaeology and museum collections is one of the most persistent challenges in the field. My research asks a simple question: Can we use digital tools to test whether fragments and museum objects might be related and, in doing so, recover parts of their histories that were previously inaccessible?

A long-standing problem in archaeology

Archaeology is, by nature, fragmentary. Objects break, decay or are disturbed over centuries. Traditionally, archaeologists have relied on visual inspection, stylistic comparison and written records to propose connections between fragments and objects. These approaches are still essential, but they also have limits. Visual judgments can be subjective, and archival documentation is often incomplete or inconsistent.

As a result, many potential links between excavated material and museum artifacts have remained speculative or have never been proposed at all. An object in a museum may appear complete yet still have a fragmented history. Without a way to test relationships systematically, fragments often remain sidelined as secondary or uninformative.

More than a century ago, the archaeologist Flinders Petrie argued that an object’s value lies not in its beauty but in the information it carries. An unremarkable fragment with a known history, he believed, could be more important than a finely made object without one. Today, digital tools are giving archaeologists new ways to put that idea into practice.

Turning objects into data that can be compared

One of those tools is 3D scanning. Using portable scanners, it is now possible to capture the full surface geometry of an object with high precision, without touching or damaging it. Every curve, contour and variation in thickness can be recorded digitally.

Once scanned, an artifact becomes more than an image. It becomes data: a detailed digital model that can be rotated, measured, compared and analyzed. Importantly, this process is noninvasive. Fragile objects do not need to be moved, dismantled or physically tested.

For archaeologists and museum curators, this process opens up new possibilities. Objects held in different institutions, or fragments stored in excavation archives, can be compared digitally, even if the originals never leave their locations.

Scanning is only the first step. The real challenge lies in comparison. Rather than asking whether two pieces look similar, computational shape analysis allows researchers to ask a more precise question: How similar are their shapes?

In simple terms, the computer compares the geometry of two surfaces. It looks at curvature, thickness and spatial relationships, measuring how closely one surface matches another. It’s like comparing a kind of geometric fingerprint.

This approach doesn’t replace expert judgment. Instead, it supports it by providing measurable evidence that can confirm, refine or challenge visual impressions. It allows archaeologists to move from intuition to testing.

When a fragment meets a museum object

In a recent study published in the journal Heritage Science, I applied these methods to Graeco-Roman Egyptian funerary artifacts made of cartonnage, a composite material of linen, plaster and paint.

I created high-resolution 3D scans of excavated cartonnage fragments and compared them with an intact funerary mask held in a museum collection. The goal was not to reconstruct the object physically but to test whether their shapes were compatible in meaningful ways.

The comparison focused on three-dimensional geometry rather than decoration. This matters because cartonnage masks were often shaped in molds: If two objects were formed in the same mold, they can share highly consistent curvature and thickness patterns even when their painted surfaces differ.

I used a distance-mapping approach called deviation mapping. After aligning the 3D model of an excavated fragment to the corresponding region of the intact museum object, the algorithm calculates the distances between the two surfaces at thousands of points. Areas where the distances were consistently small are geometrically very similar. Areas with consistently larger distances indicate that the fragment’s shape diverges from the reference surface.

In this case, the surfaces corresponded closely, with differences generally of less than a millimeter – a level of agreement consistent with production in the same mold rather than a coincidental visual resemblance.

What mattered most was not a single “match” but the ability to evaluate relationships transparently and reproducibly, using shared digital evidence.

One of the most powerful aspects of this approach is that it works across distance. Researchers can easily share digital models, allowing them to compare fragments and objects held in different institutions, without transporting fragile artifacts. Excavation archives, museum collections and research institutions can begin to speak the same digital language, reconnecting evidence that has long been separated by geography and history.

Digital tools are reshaping collections research

The work I describe here, part of my recent CRAFT Project, does not use artificial intelligence or machine learning. It relies on computer-based shape comparison and careful interpretation of metrological results. But it sits within a broader movement in heritage research.

Across the world, researchers and institutions are beginning to combine 3D scanning with machine learning to explore collections in different ways. For example, the EU-funded RePAIR project uses AI and robotics to help reassemble fragmented archaeological artifacts, while major institutions such as the Smithsonian are experimenting with AI-driven analysis of large 3D collections.

Together, these projects point to a future in which digital tools play an increasingly active role in how museums and archaeologists understand the past.

Digital archaeology is sometimes associated with flashy reconstructions or virtual displays. But its deeper value lies elsewhere. By giving fragments a new analytical role, digital methods allow archaeologists to recover relationships that were long thought irretrievably lost.

New digital methodologies are breathing new life into a long-standing archaeological principle: Modest fragments can carry outsized significance when they clarify an object’s origins and its lost context, finally allowing it to find its way back home.

This article is republished from The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/3d-scanning-and-shape-analysis-help-archaeologists-connect-objects-across-space-and-time-to-recover-their-lost-histories-273077.