Dear Nicola:

I attach 3 links to papers that talk about the relevance of the 3D representations of built cultural heritage in order to enhance the experience of the visitor in those places. I hope you find them useful.

Best regards,

Francisco

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I assume you are talking about the quantitative epistemic value rather than philosophical. The epistemic value of an archaeological or cultural heritage site's transformation into a 3D representation depends on the accuracy of the model, as considered in questions such as "True or False?", "How much is conjecture vs fact?", "How accurate is it on a scale of 1 to 10?", "Is it an empirical model?", etc. The sum value of a 3D representation is derived from the ability to learn something that was not apparent either theoretically or empirically, or as a teaching/presentation tool to the layman. Personally, for analytical purposes I would prefer 3D models to be shown using an color scale to represent the degree of accuracy.

My personal experience is that 3D reconstruction of archaeological evidence of buildings (of which generally only the lower part is conserved) is crucial to understand what the actual building may have looked like, and to analyze the architectural and engineering solutions applied by the ancient builders. The starting point are the plans and profiles of the excavated evidence (and I agree with James Green that these original data should be readily recognizable in the 3D reconstruction), but "raising" the building will show that only certain alternatives of reconstruction are possible (for example height of the walls, span of the roofs...). This opens questions that may be answered by the going back to the archaeological evidence, or that lead to enlarge the research into materials analysis (mineralogical and chemical composition, physical and mechanical properties), building systems and technological knowledge. This  increases our understanding of the culture that produced the buildings, which is the aim of archaeology. Beyond this academic value, understanding the building is  basic to design an adequate preservation strategy, a central objective in heritage conservation. Therefore, I consider the "public" value of 3D reconstruction, geared toward "enhancing the experience of the visitor", as Francisco Filip states, probably the most commonly accepted but not  the most significant epistemic value.

I think Annick and James both presented reasonable expectations of what we can achieve in 3D visualization.  Back 20 years ago when I was in the animation industry, we talked a lot about interpolation and approximation with regards to procedural CGI model building.  As Annick and James both pointed out, there is a limiting point in which the archaeological record will provide the means to interpolate data within 3D space that is consistent with the physical record.  Beyond that however, there is a substantial approximation of data, both scientifically and artistically that goes on. 3D modelling and more specifically procedural modelling allows the Archaeological multi-vocal approach to test the approximation process thus creating a more robust multi-faceted interpretation of the data.  However that process needs to be better understood scientifically from a practical 3D production pipeline perspective.

The London Charter has provided a template in which we as 3D visualizers can now engage when demonstrating the epistemic value of our visualizations.  Although not perfect, it does present a framework that compliments the archaeologists desire to communicate inwards to the community while also satisfying sometimes secondary outward public needs.  What we need to grapple with is the "artistic" approximation and interpretation of the data and how that is visually represented and of course, the multi-vocal interpretations of that data.

Great question that has engaged me to think further on my own research.

Cheers,

Michael

We think that 3-D documentation in rock art might be helpful as a means of capturing much of the data encompassed on a rock relating to the prehistoric image production.  It would be helpful for an interactive experience of a rock art site by those who are unable to directly and personally visit these locations.

We think that 3-D documentation in rock art might be helpful as a means of capturing much of the data encompassed on a rock relating to the prehistoric image production.  It would be helpful for an interactive experience of a rock art site by those who are unable to directly and personally visit these locations.

We have experimented with 3-D approach.  See our work on academia.edu

Hey Nicola - so very glad you have opened up this discussion. I am working on the same sort of research, only for underwater shipwreck sites. 

I think there are two different types of 3D visualisation. Those that are created to record and visualise the archaeological remains of a site, and those created to attempt an understanding of what it may have looked like, been used for in the past. While one may seem to be concerned with accuracy and recording as much detail, and the other with exploring ideas and concepts. I think it is wise to remember that both are interpretations of a site. While current technologies give us the ideal of vast, accurate and detailed recording they should be seen as a tool for enhancing interpretations - not giving an accurate reconstruction of a site. Accuracy after all is relative to context and what you are looking at. 

Annick, James and Michael have all given very good points on 3D vis and the current applications. I think Michael has hit the nail on the head with mentioning the London Charter and frameworks for creating 3D visualisations. We need to be aware of how we create these visualisations to understand how they are significant to archaeological research. 

Looking forward to seeing this discussion grow and I hope this has helped!

As we all realize, there are many archaeological and historical applications to 3D visualization. Anyone familiar with historical properties knows that a long-lived structure often is "set" to a time period that is felt to embody the height of its influence, such as Jefferson's Monticello. However, with 3D visualization we can now show those properties, complete with furnishings, as they possibly looked at different stages of their history.

As for Alan's rock art, 3D visualization is a great way to allow researchers and the public direct access to native heritage that often is in relatively inaccessible or hard to reach places. However, because of its sometime out of the way locations, rock art needs to be recorded correctly by using different wavelengths and lighting conditions that then can be manipulated and enhanced post-collection. The pictographs in the Black Dragon Canyon of Utah are perfect examples.

Hi Nicola, I can not add anything new to what has been mentioned already as I agree with most of it. 

Here is a paper (in Spanish) about how we used archived photographs for 3d modelling archaeological findings, rock art panels,  excavation surfaces and sections. I know many other researchers have done it too, even with images of currently destroyed sites or monuments, like Project Mosul or Palmyra Photogrammetry. 

https://www.facebook.com/Palmyra3Dmodel/

https://www.facebook.com/projectmosul/

Chapter El archivo fotográfico como fuente para la reconstrucción tr...

In addition to the London Charter are the Principles of Sevilla (http://www.arqueologiavirtual.com/carta/) specifically for the field of archaeological heritage.

I agree with Madeline. A thing is the necessary 3D survey of the existing spatial reality. Luckily today photogrammetry and laser 3d allow obtain it.

Another thing is the very different semantic interpretations that can be made on heritage. These studies should be based on the 3D survey, but these are usually large files, with much unnecessary information.

The question is what information must to contain a simplified 3D model to be a scientific representation of the heritage.

In this direction my research would have something to say ...

With all of the tools at our disposal to convert archaeological and heritage sites into 3D visualizations, let us remember that this should not be the end-all for those sites. Recent news on several firmly investigated sites that turned out to have been misinterpreted, even as late as the 1950s, should make us remember that interpretations are fluid and are dependent on the technology, understanding, and breakthroughs of that particular era. With changing technology, theory, and evidence, sites need to be reevaluated from time to time.