Functionality vs Realism in 3D Modelling

I’m currently looking through the literature on 3D reconstruction as part of my PhD, and I thought I would share here some useful points I am gathering through this process. I’ve specifically been looking at publications prior to the year 2001, attempting to discover the ideas that created this field in the first place and the theoretical and technical background to the methodology. Many of the arguments I am encountering have strong resonance with today, and are crucial to understand present discussion.

One of the most interesting points I have come across is the debate between those who strive for realism in reconstruction, and those who reject it.

 

Realistic Modelling

‘Realist’ archaeologists are harder to spot, as the computer limitations of the time allowed for little realism. Collins et al. (1993), Burton et al. (1997), Novitski (1998), Worthing and Counsell (1999) and Addison (2000) strive for photorealism in their models, tacitly expressing the need for faithful models. Later authors such as Guttierez et al. (2006) and especially Chalmers (Chalmers 2002, Devlin and Chalmers 2001, Chalmers and Debattista 2009) have attempted to create absolute models through the careful reconstruction of the environment, as well as of the architecture itself.

 

Functional modelling

In earlier literature the advocates of a functional style are more vocal. Fletcher and Spicer (1992), Salisbury et al. (1994), Winkerbach and Salesin (1994), Lansdown and Schofield (1995), Miller and Richards (1995), Pang et al. (1997), Roberts and Ryan (1997) and Strothotte et al. (1999) express dissatisfaction with realistic models, preferring a more subtle and accurate representation. Their main concern is with the risk of ‘absolute truth’, as

“[…] a photorealistic image […] suggests that detailed information has been
amassed about the objects being shown. Such images […] lead(s) viewers to the conclusion that the information is correct and contains a high degree of certainty and accuracy.” – Strothotte et al. (1999 p.1).

 

Differences

I have already discussed the issues of accuracy and the representation of uncertainty, so I will not delve into this subject at this point. It is however important to note that realistic and functional researchers are coming from two very distinct starting points. Realistic modelers tend to focus on the user experience. The reconstructions are designed for presentation, and the more visually stunning the result is, the more the users will feel involved with it. It is a path which leads to ‘presence’, haptic sheds and interactive models.

Frieman and Gillings (2007) analyse how people ‘perceive’ 3D reconstructions and virtual environments. Not only do they advocate for more realistic experiences, but they believe that this experience must encapsulate all senses.

“Instead, we have argued that, rather than analyse how space is viewed, we should fold vision back into the mix of the sensorium and focus instead on how space is perceived.” – Frieman and Gillings (2007 p.9).

Functional modelers are interested in the interpretation of archaeological data. In the words of van Dam et al:

“Scientific visualization isn’t an end in itself, but a component of many scientific tasks that typically involve some combination of interpretation and manipulation of scientific data and/or models. To aid understanding, the scientist visualizes the data to look for patterns, features, relationships, anomalies, and the like. Visualization should be thought of as task driven […]” – van Dam et al. (2000 p.27).

Although 3D Reconstructions are a visual means of presenting data, this does not mean they are an end product. They have the potential to be used to interpret, and as such they need to be simplified and abstract:

“In order to communicate […] complex information effectively, some form of visual abstraction is required.” – Winkerbach and Salesin (1994 p.1).

Functional modeling is ideal for the exchange of information, as too much detail can distract from the primary focus of the model. For presentation to the public, non-photorealistic models are not as involving, but they can be purposed to explain certain elements, and are especially important for the presentation of uncertainty (Winkerbach and Salesin 1994; Lansdown and Schofield 1995).

 

Intermediate models

Some authors approach the question differently, reaching conclusions that draw from both sides of the argument. One of the most interesting articles on this topic is Engaging places by Mark Gillings (1997). Gillings uses the term ‘hyperreal’ to describe 3D reconstructions, as for him the models are a separate entity from what they are a representation of, which go beyond the original. His main focus is on engagement. Researchers can strive for authenticity, but they will never be able to replicate the same conditions perfectly. No amount of detail inputted can accurately record the shape of every stone or the lighting of a room. Gillings however suggests that this is not even necessary, as the model’s ‘experiental depth’ is of higher importance.

Lansdown and Schofield (1995) emphasise the subjective nature of Visualisation, describing how even photographs are subjective. The way the position of the camera, the single-moment recording and the limitations of the frame mean the photographer has substantial input on the image. Similarly, even the most accurate of models are still based on subjective observations and the way they are presented cannot be objective or ‘perfect’.

 

Conclusion

Personally, I believe the division between realistic and functional models is unnecessary, as they deal with completely separate issues and are not truly in conflict with one another provided we adopt a thoughtful methodology. If the aims of the project are clear and the research thorough, then the models can assimilate aspects of either ideology. With regards to presentation, if the reconstruction’s aim is to explain or investigate specific elements, then a non-photorealistic model will provide a much better basis for research. If instead the project is used to create an emotional response from the user, photorealism will be more successful.

 

References:

Addison, A. C. (2000). Emerging Trends in Virtual Heritage. IEEE Multimedia Vol.7 No.2 pp.22-25.

Burton, N. R., Hitchen, M. E. and Bryan, P.G. (1997). Virtual Stonehenge: a fall from disgrace? Proceedings of CAA 97 pp.16-21.

Chalmers, A. (2002). Very realistic graphics for visualising archaeological site reconstruction. Proceedings of the 18th Spring Conference on Computer Graphics pp. 7-12.

Chalmers, A. and DeBattista, K. (2009). Level of realism for serious games. 2009 Conference in Games and Virtual Worlds for Serious Applications pp.225-232.

Collins, B., Williams, D., Haak, R., Trux, M., Herz, H., Genevriez, L., Nicot, P., Brault, P., Coyere, X., Krause, B., Kluckow, J. and Paffenholz, A. (1993). The Dresden Frauenkirche – rebuilding the past.  In Wilcock, J. and Lockyear, K. Computer Applications and Quantitative Methods in Archaeology Oxford pp.19-24.

Devlin, K. and Chalmers, A. (2001). Realistic visualisation of the Pompeii frescoes. Proceedings of the 1^st International Conference on Computer Graphics, Virtual Reality and Visualisation pp.43-48.

Fletcher, M. and Spicer, D. (1992). The display and analysis of ridge-and-furrow from topographically surveyed data. In: Reilly, P. and Rahtz, S. Archaeology in the Information Age pp.59-76.

Frieman, C. and Gillings, M. (2007). Seeing is perceiving? World Archaeology. Vol.39 No.1. Viewing space pp.4-16.

Gillings, M. (1997). Engaging Place: a Framework for the Integration and Realisation of Virtual-Reality Approaches in Archaeology. In: Dingwall, L., Exon, S., Gaffney, V., Laflin, S. and van Leusen, M. Archaeology in the Age of the Internet.

Gutierrez, D., Sundstedt, V., Gomez, F. and Chalmers, A. (2006). Dust and light: predictive virtual archaeology. Journal of Cultural Heritage 8 pp.209-214.

Lansdown, J. and Schofield, S. (1995). Expressive Rendering: A Review of Nonphotorealistic Techniques. IEEE Computer Graphics and Applications pp.29-37.

Miller, P. and Richards, J. (1995). The Good, the Bad, and the Downright Misleading: Archaeological Adoption of Computer Visualisation. In: Huggett, J. and Ryan, N. Computer Applications and Quantitative Methods in Archaeology. Oxford: Tempus Reparatum pp.19-22.

Novitski, B. J. (1998). Reconstructing lost architecture. Computer Graphics World Vol.21 No.2.

Pang, A. T., Wittenbrink, C. M. and Lodha, S. K. (1997). Approaches to uncertainty visualisation. The Visual Computer pp.370-390.

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.

Salisbury, M. P., Anderson, S. E., Barzel, R. and Salesin, D. H. (1994). Interactive pen-and-ink illustration. Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques pp.101-108.

Strothotte, T., Masuch, M. and Isenberg, T. (1999). Visualizing Knowledge about Virtual Reconstructions of Ancient Architecture. Computer Graphics International.

Van Dam, A., Forsberg, A. S., Laidlaw, D. H., LaViola, J. J., and Simpson, R. M. (2000). Immersive VR for Scientific Visualisation: A Progress Report. Computer Graphics and Applications Vol.20 No.6 pp.26-52.

Winkenbach, G. and Salesin, D., H. (1994). Computer-generated pen-and-ink illustration. Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques pp.91-100.

Worthing, D. and Counsell, J. (1999). Issues arising from computer-based recording of heritage sites. Structural Survey Vol.17 No.4 pp.200-210.