he Voussoir Cloud Installation by IwamotoScott Architecture carries on Gaudí and Otto’s tradition of using hanging chain models as form finding tools.
A chain will naturally hang in pure tension, and inverting this shape produces an arch in pure compression. Producing a design in compression without any torsion or shear forces allowed Gaudí to build without flying buttresses, and the Voussoir Cloud Installation to be paper thin. In the Voussoir Cloud Installation, the form was found by specifying the points where the structure was to touch the ground and then, with software developed by Buro Happold, hanging virtual chains from these points, which define the edges of the surfaces. The shape of the curve is particular to the weight of the material. In this case the very thin timber veneer produces much flatter curves than if it was made out of concrete. The hanging chain model asks the material, almost in Kahn’s words, “what it wants to be” and the material falls into place. You can play with a similar tool called CADenary developed by Axel Killian and released free of charge.