The Materials Book

239 construction. This is a problem both in terms of cost and sustainability. Designing structures that intelligently include structural performance and architectural geometry leads to beautiful, economical, and structurally optimized systems that use very little material. For example, doubly curved and rib-stiffened surface configurations offer the possibility to increase the load-bearing capabilities of a structure in a materially efficient and economical way. These structures have expressive, intricate, and nonrepetitive geometries. As a result, they can be challenging to build with traditional formwork methods that rely on single- use cut timber or milled foam, moving the problem of labor, cost, and waste from the structure to the mold needed to build it. These custom-milled formwork KnitCrete: Building in Concrete with a Stay-in-Place Knitted Fabric Formwork Mariana Popescu, Matthias Rippmann, Tom Van Mele, Philippe Block Today, advancements in computational design tools have enabled architects to explore intricate geometries with ease. Simultaneously, computer numerically controlled (CNC) machinery has facilitated their fabrication. Together, these developments may give the false impression that any imaginable geometry can be built. They have caused the onset of a paradigm shift from the mass standardization of the 1960s and 1970s to mass customization and fabrication starting in the 1990s. While digital fabrication has opened up new opportunities for the construction of complex and optimized structures, it has yet to address cost and material efficiency in custom concrete construction. Formwork for bespoke geometries can usually not be reused; it is a one-off product and therefore becomes waste after