Gradual Assemblies

Gradual Assemblies is a timber pergola designed and constructed by students of the MAS ETH programme in Architecture and Digital Fabrication, in collaboration with researchers from Gramazio Kohler Research. Commissioned by the Istituto Svizzero di Roma, the structure was built to provide shade from the intense Roman summer heat on the terrace of Villa Maraini's garden.

At the core of the project is a novel timber construction method in which short slats are held in place and locked using wood dowels. This spatially complex process leverages cooperative multi-robotic fabrication capabilities in the Robotic Fabrication Laboratory at ETH Zurich. The setup involves two robotic arms: one positions and holds a timber slat in space, while the other drills precise holes for dowels at defined angles. Pre-dried dowels, inserted manually into these holes, expand when exposed to moisture, creating strong frictional bonds without the need for nails, glue, or screws.

A comprehensive computational model was developed for the project, incorporating design development, geometry generation, stability checks, and robotic fabrication control. For the pergola, this meant determining the precise placement of 700 slats and the paths for inserting 2700 dowels. The process was organised into 22 prefabricated modules, produced over 19 days at ETH Zurich in a computationally defined sequence. These modules were transported to Rome and assembled on-site in just one week.

The Gradual Assemblies pergola demonstrates how computational design and robotic fabrication can transform traditional timber construction methods, achieving a harmonious blend of technical precision and architectural elegance.