Introduction: sol.id

sol.id is an installation for the campus of the Swiss Federal Institute of Technology Lausanne (EPFL) that uses new computational technology to create mirror-like metal plates that direct caustic light reflections to form recognizable images. Situated on the esplanade underneath the Rolex Learning Center, the installation reveals new qualities of light with the arc of the sun – qualities that are captured in the portraits of four figures who made important contributions to several fields studied at EPFL.

The technology: Caustic imaging

Light and its interaction with physical 3D objects play a fundamental role in how we perceive the world. A particularly fascinating light phenomenon is caustics, light patterns created by materials bundling or diverting light by refraction or reflection. We know caustics as random side effects, created, for example, by a wine glass refracting light onto a table or by the sun focused at the bottom of a swimming pool. Research conducted under the direction of Prof. Mark Pauly at the EPFL Computer Graphics and Geometry Laboratory has led to a new technology that makes it possible to control such caustic light patterns to form almost any desired shape by optimizing the geometry of reflective or refractive surfaces. This surprising result offers a new perspective on light control and enables fascinating new applications in diverse fields such as solar cells, laser technology, reflector design, architecture, product design, and visual arts. The key result of our research is an algorithm that computes the shape of a 3D object such that light reflected or refracted off the object creates a desired target light pattern. This research is a collaboration with several scientists and practitioners spanning diverse fields such as computer science, architecture, digital fabrication, and design. As such, it provides a showcase of how interdisciplinary research projects can bridge the gap between science and art, and even lead to new means of artistic expression. Our research has created a way of ”painting with light” that has not been accessible before and that cannot be achieved without advanced computation and fabrication methods.

The site: Rolex Learning Center

The Rolex Learning Center designed by the Japanese architectural practice, SANAA, is a laboratory for learning, a library with 500,000 volumes and an international cultural hub for EPFL, open to both students and the public. Spread over one single fluid space of 20,000 square meters, it provides a seamless network of services, libraries, information gathering, social spaces, spaces to study, restaurants, cafes and outdoor spaces. It is a highly innovative building, with gentle slopes and terraces, undulating around a series of internal 'patiosʼ, with almost invisible supports for its complex curving roof, which required completely new methods of construction.

The installation: sol.id

The installation is comprised of four reflective aluminum panels each 1 meter square and between 2 and 3 cm in thickness. The surface of each of the reflective panels has been milled using precision equipment so that sunlight reflected off the panel forms a recognizable portrait. The panels are positioned on bases fabricated from 2 cm thick steel plates formed into a cross and tilted to catch the sun’s rays. The angle of this tilt, along with the exact position of the four bases and the curved articulation of the milled surface were calculated taking into account the movement of the sun and the distance between the reflective surface and the underside of the Learning Center where the images are projected.

As the sun moves across the sky, light reflected off the aluminum panels illuminates the concrete underside of the Learning Center, revealing the materiality of the concrete and putting it into tension with the sinuous, wave-like geometry that defines the spaces underneath. Depending on the time of day and the day of the year, the portrait-figures represented within the reflections are more or less visible–more or less distorted. These portraits are not instantly recognizable–neither the person, nor perhaps as even portraits. But as students, staff, faculty and guests return to the Learning Center–each visit reveals a new awareness and instills a kind of ritual anticipation that feeds a desire to know more–passers-by themselves seek out more information about the illuminated portraits hovering above them. Through discussions with others, an instant of visual recognition, word of mouth or by accessing the project website, the identity of the figures is grasped, and enriches the reading of the project.

Just as this knowledge is revealed–through the daily encounters of time, in an instant of recognition, through exchange and argument–the project celebrates the ways scientific research leads to new forms of knowledge. The choice of the four specific figures represented in the installation is an acknowledgement of the diversity of disciplines on the EPFL campus. At the same time, the specific biographical histories of these figures reveal that each struggled with societal expectations and prejudices that weighed down their careers or tragically cut them short. Nevertheless, each made contributions to their disciplines and to society that have come to be celebrated–for some only recently, as history has shed a new kind of light on their accomplishments.

For more details about each portrayed individual, please click here.
For a simulation of the installation at different times, please click here.