Digitising Waste: Teaching Circular Construction Through Computational Workflows and Digital Fabrication

The transition toward a circular built environment requires not only technical innovation but a fundamental shift in engineering pedagogy. While theoretical models of circular economy are well-established, the practical application of reusing waste materials in structural design remains a complex challenge due to material variability and non-standard geometries. This paper presents the pedagogical framework and outcomes of a graduate-level course at Politecnico di Milano, designed to bridge the gap between theoretical circularity and digital fabrication. The methodology follows a “waste-to-resource” workflow, guiding building engineering students through three distinct phases: Urban Mining and Digitization, Computational Design, and Advanced Fabrication. The cohort was tasked with sourcing waste materials from the urban context, which were then catalogued and digitized. Leveraging a suite of computational design tools within the Grasshopper environment - including evolutionary solvers for optimization, nesting algorithms for material efficiency, and specific plugins for timber joinery students developed parametric models capable of adapting to the irregularities of reclaimed materials. The course culminated in the fabrication of five large-scale architectural structures, utilising advanced manufacturing techniques including milling and 3D printing, specifically focusing on creating bespoke interfaces and connections that facilitate dry assembly and future disassembly. This paper discusses the successes and challenges of this pedagogical model, analysing how digital tools serve as essential enabler for scaling circular practices. By treating waste as a variable input for algorithmic design, the course demonstrates that digital fluency is a prerequisite for the next generation of engineers to effectively operationalize circular economy in construction.