My main in 2014 focus will be presenting 3D CAD models of Prehistoric roofed structures using Sketchup.
At present I am working on several [competing] fronts, with active models of Stonehenge, and an interesting Native American Building at the Edwin Harness Mound. In addition, I hope to do some additional work on Roman Military engineering structures, as well as Neolithic Longhouses should the opportunity arise. The problem that there is so much I have still to publish; among the built environments I have looked at in detail is a Romano British pottery at Orsett and Bronze Age fort which has a huge forge with a smoke bay. However, as my work on Natïve American architecture demonstrates, you never what opportunities for collaboration may arise.
In this post I want to focus mainly on practical methodologies in 3D modelling of timber structures from archaeological ground plans.
I usually use squared 6”-8” section for horizontal components, but at present, I use larger naturally tapering circular pieces not only for posts, but also for the main ties and rafters, as I am still testing this idea, and observations about ‘fit’ and practicality in the may give some insight resolve these details, [right].
As archaeologist, I am uncomfortable with pictures of the past, while their appeal is self-evident, they are fictional, and more significantly, effect people’s thinking in ways which they are not always conscious of. Thus, I make a effort to undermine any illusion of reality in my illustrations; so while I use various wood textures to indicate that the structure is wooden, I have a stone wall as a background. A diagram is designed to facilitate understanding, not the suspension of disbelief.
I would expect a finished CAD Model to contain perhaps 1000 timber components, each of which has to be positioned manually in a structure with multiple axes of symmetry. So while it is simple to demonstrate from the position of the posts that this is a building and model how individual bays might work, [above left] the overall assembly is a far more complex problem. Thus it is important to spend time testing ideas on small sections of the structure, before embarking on a full build; while starting points are usually important, they are fundamental to understanding an order of assembly.
Testing the theory
At present I can build sections of the structure, but joining up all the bays and creating a full model requires yet more critical decisions. So it is important to test possible solutions to specific problems before committing resources on a full build. [Interlace theory attempts to describes the order assembly in this type of circular roof]. The particular complication is modelling additional levels of roof which effectively create a clerestory to light the interior of the building.
Presenting the evidence
One of the problems of interpreting spatial archaeological data recorded in a visual form is that is difficult to define and discuss in text. While text is the preferred method of communication of ideas, in many fields of study this breaks down, necessitating the use of maths, symbols, and diagrams.
[left] Sarah from the SketchUp Team manning a Roman Rampart Model .
The role of fictionalised visual material in influencing the course of the archaeological narrative has already been alluded to, but archaeological reports traditionally contain at least a sample of the diagrammatic material recorded during the excavation. However, its role in the subsequent synthesis is more problematic since the visual literacy necessary to understand this primary evidence is not shared by all the stakeholders in the archaeological narrative.
The use of virtual models adds another dimension to the problem; while they are perhaps simpler to understand, they are impossible to “publish” in a conventional sense. This is one important aspect I will addressing this year, hopefully by including some form of moving pictures into the blog to express some of these more complex ideas and methodologies - I hope to include start using Video later this year.