Braided mycelium composites: an integrated robotic design-to-fabrication method for bio-based fibrous building components

Mycelium-based composites offer a bio-derived alternative for transform-ing lignocellulosic substrates into lightweight building components. However, architectural-scale implementation remains constrained by mold-based form-giving, limited reinforcement continuity, discontinuous fabrication methods, and limited repeatability under conditions of high customization. This paper presents an integrated robotic design-to-fabrication method for Braided Mycelium Com-posites, a class of mycelium composites in which robotically braided, rope-scale hemp scaffolds are consolidated by mycelium to form contaminant-free and formwork-free building components. The paper presents three elements: The method comprises three elements: (i) a deposition-relevant braid specification method that converts a target boundary into ordered rope trajectories with turning and collision constraints; (ii) a rope-scale robotic braiding and toolpath strategy that maintains executable placement across multi-radius fiber bun-dles; and (iii) a biogenic junction-locking protocol that immobilizes crossovers and consolidates the scaffold over 30–45 days. The method is evaluated for architectural use-cases through scalability metrics (time and phase-dependent mass/geometry change), three-point bending (rope-scale stiffness/strength and failure morphology), and impedance-tube acoustics (normal-incidence absorp-tion). Manufacturing feasibility is linked to service-relevant structural and environmental performance. The results indicate a junction-controlled composite response while the bending of the material is governed by localized indenta-tion and progressive rind cracking rather than brittle rope rupture. Acoustic absorption remains modest across the measured band. The findings presented herein substantiate the method as a replicable methodology for the production of mold-free, contaminant-free mycelium composites. Furthermore, these findings identify the pivotal factors (i.e., junction density, placement tolerances, and sta-bilization conditions) that can be utilized to enhance the structural and acoustic performance of interior building components.