ArchéObjet 3D Project workshop held in Lyon
Applications of 3D technology to the study of small artefacts and biofacts
The study of past societies implies analysis of the remains of human activities, for instance artefacts that were modified or used by humans in the past, and biofacts, such as animal and plant remains. Artefacts and biofacts, being tangible by nature, are considered archaeological objects as they enable the reconstruction of past human life and activity.
There are several stages to the study of archaeological objects. The first steps include visual observation and documentation using drawing and photographs. Post-excavation analyses of objects is crucial, but may largely differ depending on the country, on the object’s value to society, to science, and may vary according to local conservation practices and storage resources. In the field, when far from home laboratories and their scientific resources, the required conditions for analyses are not always replicated and exporting archaeological material is rarely possible. As a consequence, from the moment objects are excavated, their analysis, conservation and display may become essential challenges. Therefore, access to archaeological objects and their conservation can have major implications for archaeological research, together with heritage preservation and public diffusion.
3D scanning has made impressive progress in the last decade due to the recent expansion of commercial 3D technology (in the field of computer games or as an industrial tool). As a result, it is becoming an effective tool in the field of archaeology. While the application of 3D laser surface scanners is not new to the field of biological anthropology, access to laser scanning technology was limited in the past due to the high cost of 3D scanners and the complexity of associated software. Expensive 3D imaging equipment such as computed tomography (CT) scanning devices, magnetic resonance imaging (MRI), and terahertz imaging (THz), has been in use for several decades in the field of archaeology. However, these imaging tools are stationary, impossible to use when the material under study cannot be moved for analysis and documentation. In recent years, portable laser or structured light scanning devices with the capacity to generate decent resolution imagery have become available. Even if their prices range widely according to accuracy and resolution levels – from a few hundred euros to more than 50 000 euros –, many scanners of reasonable quality are now affordable and simple to operate. Recent developments in hand-held 3D scanning technology now makes it possible for researchers to easily travel abroad and to archive archaeological collections in situ or housed in facilities throughout the world.
The ‘ArchéObjet 3D’ Project and its aims
For decades, the Archéorient Laboratory (CNRS & Lyon University) has been conducting fieldwork projects in Southwest Asia (namely in the Near East, Arabian Peninsula and southern Caucasus) and the Mediterranean. Years of excavation have produced large archaeological assemblages (lithic and bone industries, human and faunal remains, ceramics…) from some of the most important prehistoric and early historic sites in these regions, which has led to a growing interest in enriching the documentation process of these objects with the use of hand-held 3D scans (fig. 1).
The ‘ArchéObjets 3D’ Project is funded by Lyon University’s PALSE IPEm initiative which finances multi-disciplinary projects requiring new technological tools in the field of image capture. This project aims to develop the application of 3D scanning technology, and particularly hand-held 3D scans, to archaeology and heritage preservation. Our main interest is to explore different aspects of 3D rendering and apply them to the various archaeological specialties represented in our laboratory.
We can identify several goals and applications in the 3D rendering of archaeological objects. 3D acquisition considerably enriches the documentation of objects by capturing multiple characteristics at the same time such as the texture and surface treatment, the raw materials used, the dimensions, the morphology and the technical characteristics. The image is an archive which allows the object to be consulted at any time and in any place. 3D scans are useful for observation at different scales, from zooming in on an object, to wider comparisons between many objects. 3D technology can also be used as a heuristic tool to test reconstructions of objects and operational sequences (succession of technical gestures) in the context of artefact production. This technology can allow researchers to access the history of an object: the way it was manufactured, used and abandoned. Cases of losses of archaeological artefacts due to warfare illustrate how museums and cultural heritage could be under threat at any time. 3D scanning can serve to permanently safeguard physical aspects of objects and can therefore contribute to preserving entire archaeological collections. 3D rendering is also contributing to preserving depictions of objects made of perishable materials and their ‘footprint’ once they are unearthed, and of materials that forego destructive analysis.
In addition to the advantages of 3D modeling to archaeological research and practice, it is a great tool for teaching and knowledge transfer. By completing and increasing the size of archaeological collections, accessing an augmented documentation of objects for exhibitions, and giving different forms of access to an archaeological object: the public can go beyond looking at it, to virtually touching it. In museum mediation, 3D rendering radically transforms the feeling associated with an object, making the public interact with displays in a different way. The creation of 3D collections therefore gives access to and attracts a larger and more diverse public than with 2D images.
3D workshop in Lyon gathers experts from around the world
After acquiring two hand-held 3D scanners (Artec Spider and Eva, a structured light scanner) at the Archéorient laboratory, several months were allocated to testing our devices in different fields. Once able to obtain promising results in 3D acquisition, our aim was to apply these methods to our archaeological disciplines: what are the applications of 3D modeling, and how can 3D be used for research?
In order to explore the possibilities offered by 3D scanning, we organized an international two-day workshop in Lyon, gathering researchers with different scientific backgrounds and experiences, from different institutions and with different 3D equipment. We wanted to discover more about their experience with 3D acquisition, rendering and elaboration, as we aim to develop all applications possibly offered by 3D modeling in the frame of the analysis and elaboration of archaeological objects in 3D.
On the first day, and after a short introduction (Emmanuelle Vila and Rémy Crassard), our team from the Archéorient laboratory (Emmanuelle Régagnon, Georges Mouamar, Shadi Shabo) presented the opportunities, limitations and perspectives we encountered in our experience with the two hand-held 3D scanners. First, we exposed our general application problems, both in technical and archaeological terms. Secondly, we discussed practical examples of 3D scanning on different archaeological materials (ceramics, bones, lithics).
Avshalom Karasik (National Laboratory for Digital Documentation and Research in Archaeology of the Israel Antiquities Authority (IAA)), presented a memorable lecture on the methods employed by the IAA in their voluntary transition to the ‘Digital Era’, already carried out several years ago. The laboratory develops mathematical and computational methods to support archaeological research, documentation and visualization. Karasik presented impressive results, such as a stable and reliable algorithm that automatically finds the axis of symmetry of pottery fragments, a user-friendly interface which creates quality print drawings of the objects and a new procedure for automatic typology and classification of ceramic assemblages based on mathematical representations of cross-section profiles (Karasik & Smilansky 2008, 2011) (3D scan equipment: Polymetric structured light scanner).
From the CEPAM Laboratory (CNRS and University of Nice, France), Lionel Gourichon, Manon Vuillien and Sabine Sorin presented several initial and very promising results and methodological thoughts on a 3D geometric morphometric analysis through morphotypes of sheep and goat bones (3D scan equipment: Artec structured light scanner).
A third talk was given by Millán Mozota, Xavier Terradas and Juan F. Gibaja (Department of Anthropology and Archaeology, IMF-CSIC, Barcelona, Spain). They presented promising results of a research project focused on the 3D analysis of Neolithic flint blade cores (3D scan equipment: Breuckmann SmartScan structured light scanner).
Ceri Shipton (Cambridge University, UK) illustrated his impressive work on 3D models, applied to a variety of lithic materials ranging from Eurasian Acheulean handaxes to much recent Australasian artefacts (3D scan equipment: NextEngine laser scanner). His 3D analyses are mainly based on accurate measurements of micro-topography, of angles and various dimensions on objects. Different variables also proved useful in quantifying reduction intensity (Shipton et al. 2014).
Finally Sabrina Sholts from the Smithsonian Institution in Washington DC, concluded the first day with a fascinating application of 3D scanning on North American lithic projectile points (3D scan equipment: NextEngine laser scanner). By quantifying bifacial asymmetry among early North American projectile point styles, and asymmetric flake scar patterning on 3D models, it was possible to detect with some measure of certainty the beginning of regionalization among the early New World colonists (Gingerich et al. 2014).
The second day of the workshop was dedicated to the use of our two scanners in order to allow participants to compare them to their own scanners and to discuss their methods and techniques. We resumed our discussions of the first day with a debate on various aspects of 3D rendering, 3D modeling and 3D use in general. After Shadi Shabo’s demonstration of ceramic scanning with our Artec equipment (fig. 2 , fig. 3), Avshalom Karasik presented post-processing programs developed in IAA laboratory: ‘Pottery3D’ designed to produce archaeological ceramic drawings out of their 3D models and ‘Artefact’ for asymmetric objects. Sabrina Sholts and Ceri Shipton presented the post processing software they use (RapidWorks) and Millán Mozota talked about the practical limitations, problems and solutions while capturing 3D data with a structured light scanner.
This two-day workshop ended the ‘ArchéObjets 3D’ Project. The opportunity to engage in fruitful conversations, discussions and debates with renowned experts with different experiences was extremely inspiring. The different perspectives represented at this workshop provided participants and attendants with a more informed understanding of the way in which to use and apply 3D tools. As ‘beginners’ in this 3D modeling adventure, we felt fortunate to have been able to provide a setting and participate in a workshop with experts from all around the world who are at the cutting edge of research in this field. We wish to thank all of them to have joined us in Lyon. We will also be happy to publish their contributions to this blog in the coming weeks.
Karasik A., Smilansky U. 2008. 3D scanning technology as a standard archaeological tool for pottery analysis: practice and theory. Journal of Archaeological Science 35: 1148-1168.
Karasik A., Smilansky U. 2011. Computerized morphological classification of ceramics. Journal of Archaeological Science 38: 2644-2657.
Gingerich J.A.M., Sholts S.B., Wärmländer S.K.T.S., Stanford D. 2014. Fluted point manufacture in eastern North America: An assessment of form and technology using traditional metrics and 3D digital morphometrics. World Archaeology 46(1): 101-122.
Shipton C., Parton A., Breeze P., Jennings R., Groucutt H.S., White T.S., Drake N., Crassard R., Alsharekh A., Petraglia M.D. 2014. Large flake Acheulean in the Nefud Desert of northern Arabia. PaleoAnthropology 2014: 446-462.
Shipton C., Clarkson C. 2015. Handaxe reduction and its influence on shape: An experimental test and archaeological case study. Journal of Archaeological Science: Reports 3: 408-419.
Compte-rendu du workshop par Millán Mozota (en espagnol) : http://sepulturasneoliticas.blogspot.fr/2016/07/participacion-en-workshop-3d.html
Emmanuelle Vila est Chargée de Recherche au CNRS. Archéozoologue, spécialiste de l’Asie du Sud-Ouest. UMR 5133-Archéorient, Maison de l’Orient et de la Méditerranée, Lyon.
Rémy Crassard est Chargé de Recherche au CNRS, membre de l’UMR 5133 – Archéorient, Maison de l’Orient et de la Méditerranée, Lyon. Préhistorien, spécialiste de la péninsule Arabique.