Catoptric Surface - CODAworx

Catoptric Surface

Submitted by Chandler Ahrens

Client: Washington University in St. Louis

Location: Saint Louis, MO, United States

Completion date: 2018

Artwork budget: $30,000

Project Team


Chandler Ahrens

Open Source Architecture


Roger Chamberlain

Washington University in St. Louis


The catoptric surface is an adaptable art work that uses the sun to draw on the interior surfaces of a building. A series of 618 mirrors can each rotate independently, controlled by a computer and electric motors, to reflect daylight from the exterior deep within the building in precise locations. In this sense, each mirror can be considered to produce a pixel of daylight. The ability to temporarily draw on existing surfaces generates modifiable atmospheric effects that affects the viewer’s perception of space.


The project produces visual effects and it’s customized light levels through its ability to move. It is a robotic system where each mirror rotates independently, controlled by a computer and electric motors to reflect daylight to draw on existing surfaces in a building. The location of each pixel of light is determined by any raster-based image that is provided to the software. As each mirror rotates to reflect daylight onto a chosen location, it attempts to recreate a very low resolution version of the input image.

The result of this method of drawing with daylight projected onto architectural surfaces generates atmospheric effects that amplifies or reduces spatial perception. The pattern from the mapping of light can flatten the perception of complex geometry in a space or amplify it. What is important in this project is that the perception of space does not rely on form alone, but rather the drawn pattern, creating a visual effect of a formless atmosphere.


Housed within the Sam Fox School of Visual Art and Design, the artwork speaks to the faculty and students of art, graphic design and architecture to the nature of how drawing at the scale of a room affects the perception of space. Carmon Colangelo, Dean of the school, was instrumental in advocating for the artwork within one of the main buildings. Hamadri Pakrasi, director of InCEES (International Center for Energy, Environment and Sustainability) within Washington University in St. Louis was instrumental to provide funding and the opportunity to realize the artwork. Chad Henry, operation manager for InCEES, was also critical for managing the budget and ensuring the project met the organization’s goals.