Harvesting daylight has long been one of the performative characteristics of a façade system as a mediator between internal and external environments. Brise soleil systems are elements integrated into a façade system that reflects indirect light deeper into a building while reducing the undesirable solar heat gain from directly passing through the façade into the interior environment. More recently, heliostats have been employed to kinetically track the solar position and redirect light down through glass roofs into atrium spaces. Heliostats are typically mounted on a roof and are motorized to follow the movement of the sun across the sky, reflecting the light with mirrors. The geometric position of the mirror finds the median angle between the sun position and the target location within a building. Most of the associated discussions around daylighting in architecture revolve around a functionalist agenda of reducing energy for illumination and increasing access to daylight when a building massing is too deep. Beyond the functionalist approach, intensifying the accumulation of light provides the opportunity to modify spatial perception through the generation of atmospheric conditions and optical effects.

The Catoptric Surface research project is part of a work-in-progress investigation that explores methods of reflecting daylight through a building envelope to form an image-based pattern of light on the interior environment.  This research investigates the generation of atmospheric effects from daylighting projected onto architectural surfaces within a built environment in an attempt to amplify or reduce spatial perception. The mapping of variable organizations of light onto existing or new surfaces creates a condition where the perception of space does not rely on form alone. This condition creates a visual effect of a formless atmosphere and affects the way people use the space. Often the desired quantity and quality of daylight varies due to factors such as physiological differences due to age or the types of tasks people perform. Yet, the current mode of thought toward daylighting tends to promote a homogenous environment, meaning the resulting lighting level is the same throughout a space. This research questions the desire for homogenous lighting levels in favor of variegated and heterogeneous conditions. The main objective of this research project is the production of a unique façade system capable of redirecting daylight to key locations deep within a building. A field of reflectors located on a façade or roof redirects sunlight through windows or skylights into the interior space. The target location of the reflected light is determined by an image-based map that informs the geometric positioning of each of the façade reflectors as a negotiation between the source and target locations. The image-based approach provides a way to specifically target lighting conditions, atmospheric effects, and the perception of space.

This research avoids a purely building science approach in favor of the notion of architecture affecting human senses as well as investigating the effects generated by the architectural entity. Light can stimulate any surface, having an immediate effect on the perception of space by creating an atmosphere from a range of luminous intensity and contrast. These variable atmospheric conditions create a series of microclimates that emanate from the architectural object, yet they are perceived to envelop the people and not the building. A person’s perception of their environment is in a dynamic negotiation according to continually changing light level, contrast, continuity or fragmentation. Therefore, the generation of atmosphere affects the perceptible boundaries of an interior space, defined by the interplay between the light pattern and surface it is mapped onto. This new atmospheric environment reveals the symbiosis between the surface, light, and atmosphere in order to produce an architecture of affect.

Location: Washington University in St. Louis
Schedule: Planning 2016-2017; Fabrication 2017

Lead Artist/ Principal Investigator: Chandler Ahrens
Co-Investigator: Roger Chamberlain, Computer Science Department, Washington University
Research Assistants: Scott Mitchell (Arch.), Adam Barnstorff (Arch), Joshua Gelbard (Electrical Engineering)

Size: 40 ft. x 10 ft. tall
Media: Mirror, Aluminum, Stepper motors, Arduino boards, custom motor controller boards

Awards:
Architects Newspaper AN Best of Design 2020
Architizer A+ finalist Architecture + Light 2020
Chicago Athenaeum Good Green Design Award 2021
ARCHITECT Light & Architecture Design Award 2022