The generic term Building Information Modelling, or BIM, came into use in the early 2000s to designate software for building and construction management and cost control. More recently, under a variety of proprietary names, BIM software has been developed into a fully-fledged tool for design and construction; this AD Profile takes stock of this evolution, assessing the implications of BIM for contemporary design, professional practice and, more generally, for design theory and history. BIM software evolved for the most part independently from the more formal and tectonic experimentations in digital design of the last 20 years. The recent interest it has generated among the design professions may be due to a crucial shortcoming of digital mass-customisation in architecture: file-to-factory technologies are easy to implement at the scale of fabrication, but less so at the scale of construction, because the making of full-size buildings requires plenty of information exchange and coordination among scores of different agents and actors, human and technical alike – each in charge of different parts or aspects of the project. BIM technology was developed partly as a solution to this informational predicament, and in its more recent developments BIM software increasingly serves as an interactive tool for collaboration and participatory decision-making. Albeit to this day most BIM applications still pertain to optimisation, performance and efficiency in cost and delivery, Richard Garber emphasises the theoretical, as well as practical import of a new tool capable of ‘closing the gap’ between design intentions, architectural notations and material execution – a gap inaugurated in the Renaissance by the very invention of architectural design and of the architectural profession.