The resulting model incorporates the topography as an integral element of the reconstruction, since the topography is fundamental in defining the form and character of the site, and also determines the positioning and orientation of the interpretative structural elements. Without the topography, the reconstruction of the site would be meaningless, but the added dimension of the topography facilitates a more realistic experience of the site (for example, compare Figure ).
One version of the model employs flat bright colour shades for the reconstructed elements. Given the usual limitations of above-ground reconstructions of structures based on limited archaeological evidence, the brightly coloured structural elements have the advantage of emphasising the hypothetical nature of the model (see Figures ).
An alternative version incorporates surface texture mapping using a more realistic colour scheme (see Figure ). Wooden elements are given a wood grain finish, clay rendered surfaces are whitened, etc. but arguably the original 'Lego brick' appearance provides a useful reminder of the origins of the model.
There are a number of limitations and problems with the model as it currently stands. Amongst the archaeological problems is the fact that the tower and hall variants are too elaborate for the actual surviving evidence and hence should be viewed as place markers rather than accurate representations. In reality, the interpretation of timber-framed structures with horizontal overlapping planking is more akin to the 'garden shed' style of construction than that shown here. In addition, the model is not a complete reconstruction, as some elements of the archaeological interpretation have not been included – for example, a probable cooking area was located near to the hall, and the motte rampart was faced with dry-stone walling. Other areas where structures may have existed but for which there is no evidence have also been omitted – for instance, the palisade around the motte may have been continuous and subsequently destroyed by the twentieth-century stone quarry but heavy erosion on the sides adjacent to the quarry meant it was impossible to demonstrate this one way or the other. In any case, to have extended the existing palisade in this area would necessarily have required the topographic model to have been extended in a way that would have made it as interpretative as the structures reconstructed upon it.
There are also some technical problems outstanding, the most significant of which is the apparent 'shrinkage' of the topographic surface during the conversion to VRML which has revealed the platforms on which the tower and hall were constructed. No solution to this has been identified as yet.
The experience of developing both this approach to the modelling process and the Symon's Castle model itself suggests that the general methodology has considerable value. Furthermore, although the resulting models are not flexible in the end-user sense, this has not been designed out of the methodology – having taken advantage of the programmatic construction of the model, alternative reconstructions can be rapidly prototyped and incorporated into the kind of end-user environment demonstrated by Roberts and Ryan ( ).