• Architectural geometry
• Assembly
• Computational design
• Concrete shell
• Optimization

The design of free-form concrete shells has re-gained popularity in recent times, pushed by computational tools which allow manipulating and exploring complex shapes interactively. However, their actual fabrication, even on a small scale, still poses challenges of feasibility and cost. We propose a novel structural concept for free-form shells, in which the shape is decomposed into flat tiles, touching each other at the midpoint of the edges. Once assembled, the tiles are post-tensioned to minimize the resulting tension on the structure under service load. The outer surface is finally completed with an in-site cast that fills the gaps and activates the entire shell behaviour. We developed an automatic pipeline to manage the design process from a general input shape to fabrication.