Presented as part of the 2025 MUGAK Architecture Biennial in the Basque Country, chrYsalis explores the idea of “building castles in the air” through a lightweight architectural installation that exists between drawing and construction, imagination and matter. Developed by researchers from Fab Lab Donostia at the Higher Technical School of Architecture of the University of the Basque Country (UPV/EHU), the pavilion investigates how computational design can transform an intangible geometric concept into a built structure.
The project is rooted in an ongoing line of geometric research focused on Monge surfaces and their architectural applications. This work has been documented in several academic publications, most notably Monge Surfaces: Generation, Discretisation and Application in Architecture.
Through algorithmic programming in Grasshopper, based on the geometric principles originally described by Gaspard Monge in the late eighteenth century, the team has developed methods to generate, discretize, and explore the expressive and structural possibilities of these surfaces.
Process documentation illustrating geometric development, robotic fabrication, prototyping, and on-site assembly of the chrYsalis pavilion.
Based on this research, the pavilion generates a path aligned with the axis of the former Franciscan convent church in Donostia–San Sebastián, now home to the city’s Anthropological Museum. A double-curvature surface is discretized into a network of warped curves, producing a lightweight spatial framework that visually resonates with the ribs of the historic vaulted nave.
Rhino and Grasshopper played a central role throughout the research and design process, enabling the development of a parametric system that controls geometry while remaining adaptable to different spatial conditions. The resulting structure is intentionally reduced to only two basic components: 6 mm steel rods and cylindrical steel joints of a single type. Following the same geometric principles used to generate the surface, the rods are connected orthogonally to create a complex form through a remarkably simple construction logic.
One of the project’s primary challenges was achieving rapid assembly and dismantling while maintaining the visual lightness central to the concept. Rather than creating a permanent structure, the pavilion was conceived as an ephemeral intervention in which the acts of construction and deconstruction became part of the architectural experience itself.
The goal was to create an almost ethereal element capable of “drawing” a form in space with the minimum possible material presence.
Digital tools also played an important role during fabrication and assembly. The Robots plugin was used for manufacturing control, while Fologram enabled the use of augmented reality to position and assemble the structure directly from the digital model.
By eliminating the need for falsework and auxiliary support systems, augmented reality simplified the construction process while reinforcing the project’s underlying idea of drawing directly in space.
Beyond the pavilion itself, chrYsalis represents an intermediate milestone within a broader investigation into lightweight construction systems and complex geometries. Because the workflow is based on a parametric framework with a single node type and repeatable assembly logic, the system can be adapted to generate a wide range of forms and spatial configurations. Current research is already extending these principles toward the design and assembly of timber structures using the same geometric and constructive methodology.
Installed within the museum’s historic nave, the pavilion creates a dialogue between contemporary computational design and centuries-old architecture. As Rainer Maria Rilke wrote, “Things are nothing but the envelope of the invisible.” Through geometry, computation, and augmented reality, chrYsalis offers a compelling exploration of that idea.
CREDITS
Idea, Development and Direction: Francisco González Quintial
Model Construction, Fabrication, Manufacturing and Assembly: Edurne Argandoña Senosiain, Thais González Amor, Leticia Ochoa Rotaeche, Luis Gurruchaga Zabala, Jose Real Cambas
Collaborators: Andrés Martín Pastor, Álvaro López Rodríguez
Photos: Eduardo Espinosa Garate
Video: Jose Real Cambas
Founds: Department of Housing and Urban Agenda. Basque Country Government
