Alternative 3D Models: Multiple Vs Singular Interpretations


As part of my PhD project, over the last few months I have been researching trends in Visualisation from its incipit to today. I’m attempting to create a solid theoretical background upon which to build my own work, and in the process I am learning a lot of the philosophical and methodological foundations upon which 3D reconstruction stands.

There are many topics that I have found particularly interesting, some of which I have talked about before, and some of which I will write about in the near future. Today though I would like to concentrate on a topic I feel has only been discussed in passing: the creation of “alternative models”. Not only do I feel we need to dwell upon this subject more, I want to go against current trend to present a counterargument for their utility.

3D researchers have been advocating for alternative models from the start of Visualisation (Reilly 1992; Mathur 1997; Roberts and Ryan 1997; The Guardian 1999; Huggett and Guo-Yuan 2000). The basic idea is that it is impossible to present all hypotheses in a single 3D reconstruction, so a number of models should be reconstructed instead, each representing an alternative theory.

Alternative models fit within the general concept of accuracy. One of the major concerns with 3D reconstruction is the narrow scope for presentation of hypothetical data. Models are often built upon incomplete information, and as a result it is impossible to recreate a perfectly accurate representation of the past. There is a distinct worry amongst specialists and skeptics alike that without sufficient transparency 3D reconstructions may misinform and deceive an uninformed user (Bayliss 2003; Kensek et al. 2004; amongst many others). This concern is certainly founded, and while some suggestions have been put forward in an attempt to minimise the problem (Pang et al. 1997; Strothotte et al. 1999), the lack of a cohesive and enforced set of principles limits the reliability of 3D reconstruction as a methodology. We are moving in a positive direction, and publications such as the London Charter offer legitimisation of the use of these technologies (Beacham et al. 2006; Denard 2009). Yet there is still a need for enforced guidelines that can reduce, or at least explicitly state. inaccuracies.

The use of pink cement (Lock 2003), or Dell’Unto et al.’s (2013) levels of accuracy are good approaches to the problem, and the literature has embraced such ideas for the better. Alternative models, on the other hand, have been lurking in the background, often mentioned but never fully discussed. They are mostly used as an addendum or a failsafe, an attempt to silence any possible critic of the accuracy of the models. It is interesting how most of the publications that mention alternative models do not present alternative models themselves: papers concerned with the theoretical background use it as an example of ways to preserve accuracy, while technical papers omit alternative models altogether (with a few exceptions i.e. Roussou and Drettakis 2003). It is also important to note that they are always mentioned positively.

I would like to present a counterargument. I do not believe alternative models are bad, or that they have no uses. There are certainly occasions in which they can convey information more efficiently than other methods. I do however believe that they have a limited scope, and that using them as a way to present inaccuracies is counterproductive to the defining of a 3D methodology.

The limitations of alternative models can be expressed as so:

  • Physical and publication space managment
  • Time requirements
  • Multiple hypotheses representation

Physical and publication space management: using alternative models to present inaccuracies to the public or to fellow researchers requires for this information to be readily accessible. At present the issue with 3D documentation is one of space. Publications often do not possess enough space for a full documentation of the reconstruction process, and the problem is exacerbated in heritage management where information has to be tailored to an uninformed public. In most cases, the presentation needs cannot accommodate the presence of multiple models. Metadata and paradata are beginning to appear in publications through the use of online repositories, but the handling of multiple large models is still problematic.

Time requirements: 3D reconstruction is a process, which follows a number of steps. Work by Guidi et al. (2012; 2014) show an ideal example of the reconstruction procedure, with accumulative levels of detail and archaeological checks at the end of each phase. In order to reconstruct most alternative models, the split must occur right from the volumetric model. By doing so each variant must be constructed individually, or the subsequent changes must be reflected in each of the different models. Attempting to change the model in the later stages of production is still possible, but it requires more work, as there are more elements that need to be manipulated. Either way, the results is a distinct increase in the production time.

Multiple hypotheses representation: another logistical problem has to do with models with many conjectures. When is it necessary to create multiple models? If we are too strict with our definition of inaccuracies then every element in the reconstruction is in question. We would therefore end with numerous models with very subtle differences. On the other hand, if we we were too lax the purpose of using alternative models is void, as displaying only some of the hypotheses would render this process redundant. Additionally, if many hypotheses were to be displayed through alternative models, it would be necessary to create a model with every possible arrangement of hypotheses, exponentially increasing the number of reconstructions.

In addition to these limitations, my argument against the misuse of alternative models has to do with traditional methods of presenting archaeological data. Archaeological reports often attempt an objective analysis of the archaeological evidence, describing what has been found and trying to limit conjectures, frequently presenting multiple theories. Yet when interpreting an archaeological site, it is not uncommon to create a narrative. Certain evidence is omitted and new meaning is imposed on the remains, in an attempt to justify the current archaeological interpretation. Part of the scientific method is to present the data and propose a unifying theory, with the expectation that the theory shall change when new evidence comes to light. And archaeology subscribes to this view: while multiple scenarios may be presented in publication, there is often one preferred interpretation.

Therefore, in traditional archaeology the data is analysed to produce the results. Objective data is transformed into subjective interpretation, and with a change in the data comes a change in the interpretation. The uncertainty is accounted for in the source and not the output and the same should be true for 3D reconstruction. Metadata and paradata are paramount for the replicability of the process and for validating the hypotheses shown in the results. We must find better ways of preserving and presenting this form of information, to ensure the 3D methodology is valid. Alternative models however are part of the output, where subjectivity is allowed and even encouraged.

Critics often note that in Heritage Management the public is more susceptible to misinformation, making 3D reconstruction a ‘dangerous’ tool. Yet museum displays often present a single narrative, reducing complex archaeological issues to simplistic linear stories. While it is still a problem 3D reconstruction needs to address, the discussion has wider implications in the way we present data to the public.

Additionally, I am not saying that alternative models cannot have uses in archaeological presentation. In some cases the conflicting theories are at the core of the discussion, and alternative models help create a virtual representation of what this conflict appears like visually. A good example of this is the Patay-Horvath (2014) paper regarding the positioning of statues at the Temple of Zeus at Olympia. Here the alternative models are used effectively to communicate the main argument. It was however a deliberate choice from the author, and it had a specific purpose.

In conclusion, alternative models are not always the best option for presenting inaccuracies. While occasionally they can be effective in demonstrating conflicting hypotheses, in a wider methodology for 3D reconstruction they have little space. Presenting metadata and paradata still offers the best course for demonstrating uncertainty.



Bayliss, R. (2003). Archaeological Survey and Visualisation: the View from Byzantium. Late Antique Archaeology Vol.1 No.1 pp.26-313.
Beacham, R. C., Denard, H. and Niccolucci, F. (2006). An Introduction to the London Charter. The E-volution of ICTechnology in Cultural Heritage.
Dell’Unto, N., Leander, A. M., Ferdani, D., Dellepiane, M., Callieri, M., Lindgren, S. (2013). Digital reconstruction and visualisation in archaeology: case-study drawn from the work of the Swedish Pompeii Project. Digital Heritage International Congress pp.621-628.
Denard, H. (2009). The London Charter: for the computer-based visualisation of cultural heritage.
Guidi, G., Russo, M., Angheleddu, D. and Zolese, P. (2012). A Virtual Connection between Past and Present: the Digital Revival of Cham’s Architecture (Vietnam). Virtual Systems and Multimedia pp.361-368.
Guidi, G., Russo, M. and Angheleddu, D. (2014). 3D survey and virtual reconstruction of archaeological sites. Digital Applications in Archaeology and Cultural Heritage 1 pp.55-69.
Huggett, J. and Guo-Yang, C. (2000). 3D Interpretative Modelling of Archaeological Sites/ A Computer Reconstruction of the Medieval Timber and Earthwork Castle. Internet Archaeology 8.
Kensek, K. M., Swartz Dodd, L. and Cipolla, N. (2004). Fantastic reconstructions or reconstructions of the fantastic? Tracking and presenting ambiguity, alternatives, and documentation in virtual worlds. Automation in Construction pp.175-186.
Lock, G. (2003). Using Computers in Archaeology: Towards virtual pasts. Routledge: London.
Mathur, S. (1997). Three Dimensional Representation of Archaeological Data in American Archaeology. Available at: Last accessed: 31st Oct 2017.
Pang, A. T., Wittenbrink, C. M. and Lodha, S. K. (1997). Approaches to uncertainty visualisation. The Visual Computer pp.370-390.
Patay-Horvátz, A. (2014). The virtual 3D reconstruction of the east pediment of the temple of Zeus at Olympia – an old puzzle of classical archaeology in the light of recent technologies. Digital Applications in Archaeology and Cultural Heritage 1 pp.12-22.
Reilly, P. (1992). Three-dimensional modelling and primary archaeological data. In: Reilly, P. and Rahtz, S. Archaeology in the Information Age pp.92-107.
Roberts, J. C. and Ryan, N. (1997). Alternative Archaeological Representations within Virtual Worlds. In: Brown, R. 4th UK Virtual Reality Specialist Interest Group Conference – Brunel University pp.182-196.
Roussou, M. and Drettakis, G. (2003). Photorealism and Non-Photorealism in Virtual Heritage Representation. First Eurographics Workshop on Graphics and Cultural Heritage.
Strothotte, T., Masuch, M. and Isenberg, T. (1999). Visualizing Knowledge about Virtual Reconstructions of Ancient Architecture. Computer Graphics International.
The Guardian (1999). Megabytes of megaliths. 23rd September 1999.

Paper on Using Unity3D for Archaeological Interpretation

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Just a quick note to say that I have published an article for Archaeological Science: Reports regarding the use of a Unity3D script to calculate solar alignment at Ggantija, Gozo.

It is unfortunately not as open access as I would like, but I’ve been told that the article will be available for viewing for the next 50 days at,rVDBK0IJ

If you have an interest in using 3D Reconstruction for analysis do check it out, and feel free to get in contact at for more information.


Paul Reilly and the origins of 3D Reconstruction

Archaeology is all about looking at the past to understand the present, and in a similar guise to fully understand the basics of modern theory we have to delve into its origins. For this purpose, today I would like to take you back to 1989, when computer Visualisation was in its infancy.

The paper “Data Visualisation in Archaeology” by Paul Reilly (1989), and the later book “Archaeology and the Information Age” by Reilly and Rahtz (1992), were a crucial stepping stone for popularising 3D Reconstruction and introducing the theoretical background that is still important today.

3D Reconstruction saw its first applications in archaeology as early as 1985, when Woodward created a model of Roman Bath and of Caerleon, adapting software originally designed for industrial engineering (Smith 1985; Delooze and Wood 1991; Palamidese et al. 1993). Between then and 1989, a number of models had been created. Yet, the theoretical background was quite sterile, partly due to a division of roles between the researcher (archaeologist) and the modeller (computer designer).

Reilly’s paper “Data Visualisation in Archaeology” (1989) starts with a common problem in archaeology: the abundance of data. Due to the destructive nature of the excavation methodologies archaeologists resort to extensive recording of contexts, generating vast quantities of information in the process. Reilly demonstrates through examples what it it possible to achieve with this data. Apart from distribution maps which are more GIS territory, he uses examples of WINSOM models to demonstrate the potential for presentation of 3D modelling. More importantly, he argues that

“[Modelling] allows the researcher to demonstrate in strong visual terms how the interpretation relates directly to the collected data. […] it stimulates the researcher to look for further information. This may involve the application of extra analytical experiments on the existing data, or it may require the formulation of a completely new research design to answer the outstanding questions. – Reilly (1989) pp.577”


“[…] reconstructions require the modeller to define explicitly each and every element in the model and their spatial relationship to one another. The definition of the model forces the researchers to reconsider the original data, which can focus attention on problem areas and gaps, thus causing them to observe, or record differently, certain types of evidence in a future investigation. – Reilly (1989) pp.578“

These ideas are found again in a section Reilly contributed to Burridge et al. (1989), in which he argues that 3D Modelling can bring to light discrepancies in the original data.

Following “Data Visualisation in Archaeology”, Reilly published a series of articles that helped solidify his theories. Reilly and Shennan (1989) look at presentation, arguing that 3D navigation can help understand archaeological contexts by displaying large quantities of data in a small amount of time. “Towards a Virtual Archaeology” (1990) provides an overview of examples in 3D Reconstruction, and demonstrates the use in recreating monuments. It also outlines how this software could be applied to the teaching of archaeological excavation. In his 1991 contribution to Computing in Archaeology, he emphasises the importance for analysis and presenting, while also recognising that realistic models may lead to the assumption of “absolute truth”. Many of the concepts here expressed are still exceptionally relevant to modern theory, and have been debated by scholars for the three decades following Reilly’s publications.

His most important contribution is however “Archaeology and the Information Age”, edited with Rhatz (1992). This collection of truly fascinating articles are the founding stone for all future 3D Reconstruction, as well as other fields of digital media in archaeology. “Archaeology and the Information Age” explores the use of 3D for interpretation, arguing that pretty pictures should not be the main goal.  Through various examples, Reilly demonstrates the potential of 3D modelling for analysis, citing the reconstructions of Sulis Minervae, Bath and many others. Other authors in the book discuss issues of accuracy, simulation and subjectivity (I particularly enjoyed Molyneaux 1992).

Throughout the 1990s Visualisation saw an exceptional rise in popularity and the theoretical background developed in these years is still applicable today. Yet it all started with a handful of researchers, of which Reilly was the forefront (with the help of Shennan and Rahtz). If you are just starting to get into Visualisation, reading some of his works is a great place to start.



Burridge, J. M., Collins, B. M., Galton, B. N., Halbert, A. R., Heywood, T. R., Latham, W. H., Phippen, R. W., Quarendon, P., Reilly, P., Ricketts, M.V., Simmons, J., Todd, S. J. P., Walter, A. G. N. and Woodwark, J. R. (1989). The WINSOM solid modeller and its application to data visualisation. IBM Systems Journal pp.548-568.
Delooze, K. and Wood, J. (1991). Furness Abbey Survey Project – The Application of Computer Graphics and Data Visualisation to Reconstruction Modelling of an Historic Monument. Computer Applications and Quantitative Methods in Archaeology pp.140-148.
Molyneaux, B. (1992). From virtual to actuality: the archaeological site simulation environment. In: Reilly, P. and Rahtz, S. Archaeology in the Information Age pp.192-198.
Palamidese, P., Betro, M. and Muccioli, G. (1993). The Virtual Restoration of the Visir Tomb. Visualisation pp.420-424.
Reilly, P. (1989). Data visualisation in archaeology. IBM Systems Journal 28(4) pp.569-579.
Reilly, P. (1990). Towards a virtual archaeology. In: Lockyear, K. and Rahtz, S. Computer Applications in Archaeology pp.133-139.
Reilly, P. and Rahtz, S. (1992). Archaeology in the Information Age. Routledge: London.
Reilly, P. and Shennan, S. (1989). Applying Solid Modelling and Animated Three-Dimensional Graphics. Surface And Solid Modelling and Image Enhancement pp.157-165.
Smith, I. (1985). Sid and Dora’s bath show pulls in the crowd. Computing pp.7-8.