For a 100m2 ceiling above a studio in Seehof Castle in Lunz am See, 130 different 3D-printed concrete recess bodies were digitally planned, automatically produced and moved on the construction site. The architectural implementation is a symbiosis of an immersive spatial effect, static effectiveness and resource efficiency. The wide-span roof construction stands for a sustainable approach to the use of reinforced concrete, which relies on economical digital production methods to save resources.