Responsive textiles vs. reactive façade systems

Published On: November 1, 2013

Research illuminates the possibilities for creating textile second building skins that can be “controlled” by the environment and user preferences.

Structures are designed and built to offer people protection and comfort. New research seeks to change views concerning how people may interact with buildings and buildings with their environment—not if, but how. This research demonstrates how textiles can react to environmental stimuli, or respond to human “requests” for a fabric façade to behave a certain way or to elicit a certain behavior in order to provide the kind of environment or protection desired—sun or shade, shielding from the wind or letting the breeze in for comfortable evening relaxation.

An imaginable product resulting from the further development of this work might be a communication platform implementable to a variety of façade or roof systems. The application would register all outlooks of which the geometry is capable, sense user movements and environmental data, and optimize and simplify the relationships among all these factors. It would then directly communicate with the building management system and dictate the deformation of the façade elements. It could be installed on users’ smartphones or on screens mounted in the building.

The designed façade or roof does not necessarily have to be highly intricate or geometrically and technologically complex to do this, but it has to allow diversity, movement, adaption and “dialogue” with the environment.

“Responsive” and “reactive” defined

To make the term “responsive” more understandable, a look at common approaches to shading systems is necessary. Recent innovations in parametric architecture allow for finely controlled and adapted façade systems that react to diverse building and user needs.

The control of the elements refers to both their shape and production (individually designed units, perfectly adapted to their position in the building, CNC [computer numerical control] machine-assisted fabrication) and to the refined functioning and timing of the façade. This is made possible by sensors and actuators, but also by research during design of all scenarios in which the system must function. These include different weather conditions and the preferences of the building’s users; therefore the façade must provide a well-adapted state/shape for each of the impulses received from the user.

During the design phase, the possible states of the building skin are well documented; each user command triggers a foreseen reaction of the system and therefore a specific shape of the façade. The user has, in this case, complete and direct control of the façade system and technology, and the system form is inflicted upon the material from the outside. Similarly, the system is reactive and not responsive.

Façades that have the ability to interact with their surroundings and are capable of an adaptive behavior are regarded as responsive. In this case, the user does not control the technology directly, but the façade exhibits a change in the containing environment and the form represents a capability of the system, not the result of the unidirectional command-reaction user influence. It is an emerging phenomenon arising from the instability of the system given by the multitude of parameters interacting with the facade, remaining open and indeterminate.

This shift in perspective, where formal becomes behavioral and motion takes over image, helped narrow down the research goal. Material systems were investigated, the configurations of which allowed the indeterminacy and the inherent instability required by the purpose of continual adaption and self-organization in a dynamic context.

User friendly

The user has the ability at all times to interact with the façade and select a desired effect: light or shadow and the size of the desired effect; local, entire room or multiple rooms. If the desired effect is light, then the geometry that leaves the least shadow on this surface projection is searched, and if the effect is shadow, the geometry that leaves the largest shadow on the surface is to be found. The order in which the geometries are considered is the one defined by the current weather evaluation; therefore, the end result is a façade made up of stripes deformed to states that best behave in the current conditions and at the same time respect the user’s choice of façade effects.

If the weather is not critical (as it would be in storm conditions) the user’s influence can become more relevant for the final outlook if they so wish. Inversely, if the user does not express strong specific wishes, the façade will take the most energy efficient shape.

There are a vast number of possibilities that an apparently basic building envelope offers if its transformation is specific to the employed materials. The method created is innovative in terms of extending the limits of user-façade interaction. One does not overpower the other; the surrounding environment and the user’s influence are at all times simultaneously relevant, in a dynamically changing balance.

The article is a further development of the work “Responsive Textiles,” conducted by Elena Vlasceanu as a diploma project at the Institute of Building Structures and Structural Design, University of Stuttgart, Germany, under the supervision, and with the collaboration of, Dipl.-Ing. Julian Lienhard and Prof. Dr.-Ing. Jan Knippers.