The "Future Tree": a pilot project for parametric planning

The "Future Tree" open outdoor pavilion in the inner courtyard of the new extension by Basler & Hofmann in Esslingen stands for the potential of parametric planning. It enables a com-pletely new design language with simultaneous optimised functionality.

 
 
 

The latest extension by Basler & Hofmann in Esslingen is situated at the rear of the existing office building. With its two side wings it forms an acute angle. This creates an inner courtyard that offers an ideal space for an interesting architectural shape. Here, an open outdoor pavilion was to be created that would attract attention from both the ground floor and the floors above. In an iterative design and planning process involving Gramazio Kohler Research, the Chair of Architecture and Digital Fabrica-tion at ETH Zurich, Erne Holzbau and the structural designers at Basler & Hofmann, a tree-like con-struction has been created that bears the name "Future Tree". A curved, honeycomb-like wooden con-struction forms the roof, which seems to float almost freely. Only on closer examination do the or-ganically-shaped concrete columns on which it rests become perceptible. Both components were planned parametrically and built using innovative digital manufacturing methods.

Iterative optimisation of architecture and load-bearing behaviour

Both the "crown" – a wooden reciprocal framework – and the "trunk" – a structured concrete column – were parametrically designed by researchers at ETH Zurich. Specifically, the design intention was recorded in program code using various parameters. Once programmed, countless shape variants can be generated within a short period of time. In the parametric model, for example, the mesh size, joint size and curvature of the reciprocal framework was able to be changed and the entire geometry of the structure adapted automatically. As the model was linked with the static programs, Basler & Hofmann's structural engineers were able to quickly determine the effects of a change in geometry on the load-bearing behaviour. In this way, the architectural design and load-bearing behaviour were co-ordinated and optimised in an iterative process.

Automated construction processes

Parametric planning produces highly complex structures that would be virtually impossible to build by hand alone with the necessary precision. Robots and 3D printers were therefore involved in the con-struction of the Future Tree. An Erne Holzbau robot cut the wooden elements of the reciprocal frame-work to shape, pre-drilled them and positioned them within the space. The concrete column of the pavilion is the result of a new construction process developed by ETH Zurich in which a 3D printer produces an extremely thin formwork, which is then filled with a special concrete mixture. In October 2019, the "trunk" and "crown" came together in Esslingen.

 
 
 
 

Project stakeholders:

Building owner: Basler & Hofmann AG

Architecture and technology: Gramazio Kohler Research, Chair of Architecture and Digital Fabrication, ETH Zurich

Structural analysis and construction: Basler & Hofmann AG, Erne AG Holzbau / SJB Kempter Fitze AG

Development of construction methods and production – timber construction: Erne AG Holzbau

Development of construction methods and production – concrete columns: Gramazio Kohler Research, ETH Zurich and Chair of Physical Chemistry of Building Materials, ETH Zurich

Architecture office extension: Stücheli Architekten