This research explores the integration of carbon fibre structural networks within large-scale 3D printed polymer architectural skins. The paper is focused on two projects, Cloud Affects and B515 Studios, which experiment with the algorithmic generation of structural networks and their fabrication through sacrificial formwork strategies. These projects are positioned within a lineage of iteratively developed projects that establish a co-evolution of fabrication technique and tectonic logic. The research demonstrates a codependent relationship developed through the feedback of generative design processes and the refinement of large-scale fused deposition modeling (also known as Big Area Additive Manufacturing, or BAAM). The implications of this co-evolution are explored here in terms of form, structure and detailing.