Appendix A: Infrastructure digital technology requires systems-thinking

The purpose of this appendix is to relate the systems-thinking of Doing it Differently to developments in digital technology, and specifically to building information modelling (BIM). The following is not a tutorial in the use of BIM. It is rather an introduction to the major developments in software engineering, their conceptual influence on the development of BIM, both now and in the future, and a discussion of their relationships to systems-thinking.

In the second half of the 20th century, as computers began to be used for wider purposes than technical calculations, one of the first applications was to automate the task of drafting technical drawings. Drawings have long been an effective way of visual communication. The expressive sketches, drawings and paintings of the visual arts communicate subjective interpretations of meaning. Technical drawings are quite different – they are two-dimensional (2D) drawings of plans, elevations and sections intended to communicate information so precisely that only one interpretation is possible. Several commercial packages became available. As computers became ever-more pervasive and less costly, that process rapidly became absorbed into computer-aided design (CAD). By the 1990s object-oriented programming became popular, using languages such as C++ and Java. CAD systems began to replace 2D symbols with computer objects, such as walls and window frames and even abstract objects such as a space. This allowed the user to see multiple views together with various non-graphical attributes and geometric and functional relationships. These could be explored and edited (e.g. walls could be stretched, joined, have height, be of a specific cross-section type and have properties such as a fire rating or an insulation value).