Over twenty years ago, I bought a computer and CAD software, only to discover that it took hours to print a shaded view of an Iron Age roundhouse, and besides, sticking a cone on top of a cylinder did nothing to advance my understanding of the archaeology of prehistoric timber buildings. So I returned to the basic data and to working on paper in plan, section, and elevation. Prehistoric structures in Britain are largely evidenced by postholes, often in such numbers, that most archaeologists are content to pick out circles and rectangles on which to base their report, and ignore the rest of the dataset. However, thinking about structures in terms of 'shape' has led to simplistic models and inappropriate cross-cultural comparisons. My research into understanding postholes has concentrated on reverse engineering timber structures from the known position of their posts, which ultimately leads to a consideration of how timbers were joined together. Initially, I worked back from the medieval period, but more recently, I have worked forward from LBK buildings, which are the starting point for the range of technologies that both require, and support, complex built environments. Modelling the relationship between an archaeological ground plan and the original superstructure requires a detailed consideration of tools, carpentry, building technology, and trees. It leads to ideas like offset jointing, reversed assembly, and importance of ties, unfamiliar concepts to most archaeologists. However, with such ideas comes a basic set of principles that both explain the spatial distribution of archaeological features, and are a guide to the use of CAD to reconstruct and understand prehistoric architecture on a timber-by-timber basis. Understanding the basics of posthole archaeology, and the technological culture it represents, unlocks the potential of CAD systems a research tool, making it possible to reconstruct buildings from LBK longhouses to Woodhenge in virtual reality.
