In our last post we mentioned texture mapping as an approach to revealing material detail and surface quality in heritage modelling. Texture mapping is where a high resolution photograph or composite digital artwork is applied (or “pasted”) onto the surface of a 3D digital object. Using high resolution photographs of the actual surfaces of a historic building for this brings with it a number of advantages which for some of our AHRC funded Community Heritage projects can be a significant part of telling their buildings’ stories because the surface detail holds vital architectural and archaeological clues about how the building developed. The buildings belonging to our AHRC Community Heritage partners the Wigston Framework Knitters Museum are a case in point. We have been producing an un-textured, developmental animation sequence with them showing how the building has evolved in a series of well defined phases from a small single storey cottage to a larger complex of early industrial buildings for hosiery manufacture.
Much of the understanding of that sequence has come from a careful examination of the brickwork of the buildings. To a trained eye the changes in brick types, sizes, positions, bonding and weathering as they survive today can be read like a book, helping us to decode the story of the buildings. But we have to be careful in how we present this information because we cannot be sure that every brick and slate we see today are exactly the ones that were present at any particular previous phase – some could have been replaced within or after a phase but still conform to the phase’s overall form. Furthermore even if they are the same they would not have looked in the past exactly as they do now because of weathering, erosion and discoloration. It’s therefore of methodological importance in representing the earlier phases of this development that they are in fact not texture mapped and this is why we’ve used white, un-textured “clay” renders for all phases before the present day to show the form of the building (albeit in some considerable detail) based on an interpretation of the present brickwork. We only show the texture-mapped version in the last phase, that of the present – the only phase we can absolutely certain about.
The brickwork itself of interest in that some of it is Diapered. This a form of brickwork patterning where different coloured bricks are used as a decorative treatment in walling with a repeat pattern of squares (chequers), rectangles, or lozenges. It’s often constructed using Flemish diagonal bond which is a complex pattern of stretcher courses alternating with courses of one or two stretchers between headers, at various offsets such that over ten courses or so a diamond-shaped pattern appears. Incorporations into the brickwork like ironwork and timber are also of historical and architectural significance and at in the gable end of the Wigston Framework Knitters Museum there are the remains of a timber cruck frame of a once adjoining building. Because it lies flush with the brickwork it is virtually invisible in a “clay” rendered model, but using texture mapping it becomes immediately apparent and can be used to communicate an important aspect of the building’s physical and historcal context. By combining true to life, carefully measured and detailed 3D, geometric modelling of the building with photographic texture mapping a very high fidelity reconstruction can be produced, one which combines the advantages of both techniques but does require careful reflection on precisely how and why they are used and on what.