Design data issues for the control of mega-scale rapid manufacturing

Construction has traditionally relied on specifications and 2D drawings to convey material properties, performance details and location information. The use of advanced 3D solid modelling and digital fabrication methods are enabling the construction of Iconic buildings with an emphasis on the visual design of form. The integration of function with structure, however, has not yet been realised. Rapid manufacturing technologies are able to create physical objects directly from 3D solid modelling data by computer controlled additive processes. Components can be produced with any geometric form and can add further value through integrating function. Large scale versions of these processes are now being investigated for construction applications and an important aspect of these machines are the build instructions. These are created in a series of discrete steps from the design concept, encapsulated in the digital model, through to the machine code instructions. The use of the language used to describe precision, accuracy, tolerance, resolution and minimum feature size are blurred by the use of manufacturing based processes applied to create a new type of construction. This paper explores these issues and offers definitions of these terms in relation to mega-scale freeform fabrication processes for construction.