Complex shapes in wood: Computer-aided design and manufacture of wood-sandwich roof shells

Computer-Aided-Design, Engineering and Manufacturing (CAD/CAE/CAM) technology has changed the way consumer products, automobiles or airplanes are designed and made. The emerging applications for CAD/CAE/CAM technology in architecture, and the way this technology impacts how we design and construct the built environment, are yet unclear. This thesis investigates the relation between advanced digital design tools and the making of physical objects by focusing on an exemplary architectural element—wooden roof shells. The research objective is to expand the scope of architectural design through the application of CAD/CAE/CAM technology rather than to use this technology to streamline existing processes. The thesis develops a specific technical solution that allows the design and manufacture of new types of wooden roof shells. These are complexly shaped multifunctional construction elements that are manufactured off-site. Based on the close connection between digital design tools and the new Computer-Numerically-Controlled manufacturing process the author proposes a theoretical model of shared digital environments for collaborative design in architecture. The proposed manufacturing process treats wood as a modern composite material. Thin wood strips and foams combine into structural sandwich panels that can then be joined into a roof shell. The geometrically complex panels are generated by a combination of subtractive Computer-Numerically-Controlled machining processes and manual work. Infrastructure elements can be embedded into the sandwich build-up in order to enhance the functionality of the roof as a building envelope. Numerical tools are proposed that allow the determination of manufacturing-related parameters in the digital design environment. These inform the architectural and structural design in the early design phases. The digital collaborative design environment is based on a shared parametric solid model and an associated database. This collectively owned, feature-based design model is employed throughout the design and manufacturing process and constitutes the means of concurrent design coordination of all participants. The new manufacturing process for wood/foam sandwich shells is verified by designing and manufacturing prototypes. Design guidelines and a cost estimation are presented as the practical basis for architects and engineers to incorporate new types of roof shells into architectural projects.