Upcycling of regular wood trunks and logs using wave function collapse (WFC), augmented reality (AR), and mixed reality (MR) technologies for circular design.

In sustainable building design and construction (SBDC), irregular timber elements, such as unprocessed logs, forks, and branches, remain significantly underutilised due to their complex geometries, which complicate reconfiguration and lead to considerable material waste. This study addresses this challenge by introducing a computational workflow that optimises the upcycling of irregular wood into feasible building components. The CAAD contribution of this work lies in applying Wave Function Collapse (WFC) as a digital aggregation method, enabling automated spatial configuration of irregular wood elements. This method integrates 3D scanning, algorithmic aggregation, and finite element analysis (FEA) to assess structural viability, ensuring efficient material utilisation. For joinery experiments, our engineering application involves the development of a heat-moldable joinery method using recycled PET bottles, which eliminates the need for adhesives or mechanical fasteners. By leveraging the heat-shrink properties of PET, structurally stable connections are formed between upcycled wood components. The proposed framework is demonstrated through the fabrication of functional furniture and pavilion-scale architectural prototypes, showcasing an innovative approach to material repurposing. This study advances Computer-Aided Architectural Design (CAAD) and construction techniques by 3D scanning, volumetric design, AI-driven building scale ideation and Augmented Reality (AR) and MR-assisted assembly, demonstrating scalable solutions for sustainable architecture and circular material reuse.