Within the modern discipline of measured architectural drawing,
the two-dimensional representation of buildings has required two systems of reference; one between the representation and the building being represented; the other internal to the representation itself, connecting its elements and translating across viewpoints to produce a coherent, complete, and consistent description. This presentation offers a theoretical,
historical, and technical discussion of a transition point in the understanding and use of conventionalized systems of internal reference in architectural production drawings as a number of often large American firms explored the use of “overlay drafting” from the late 1960s to the early 1980s. Through these explorations and new practices of reference on which they depended, conventional interrelationships between drawings, other forms of building documentation, and the work of architects generally were reimagined in terms of information and management. Tracing the impacts of this reimagination uncovers how seemingly banal drawing elements and practices provided many of the techniques, concepts, and metaphors which became central to the expansion of early efforts to create computer-based documentation practices and which underpin many of the most advanced Building Information Modeling tools in use today.