Sunwork is a three-year empirical study of the sun’s movement in the sky. The project began with the construction of a small instrument, or “sunbox,” to study, record, and render visible the apparent paths of the sun and its temporal and geometric attributes in the local sky. At a much larger and public scale, a second sunbox developed a spatial and tectonic (or architectural logic) based solely on the measure of the sun’s passage over a place. The central innovation of the sunbox is its use of projected light in construction, conflating media with medium, or drawing with building.

Light as Time

Sundials are catchers, recording instruments, translators of light into time. The earliest of time-keeping instruments, sundials rendered time and movement visible by casting a shadow from a gnomon onto a scale. The Sunbox project began with the inverse proposition: instead of casting a shadow, it would cast light through an aperture to a spot on the ground. Whereas the gnomon records sunlight continuously, casting light through an opening punctuates time, similar to the difference between reading a clock and hearing a bell. Casting light became the basis for the first sunbox, an enclosure of four walls with a series of apertures. These openings were positioned to channel light from the sun at different hourly points on the twenty-first day of each month to a single mark on the ground at the center of the box.

Light as Line

The first sunbox utilized both trigonometric calculation and projection drawing. Initial data from the National Naval Observatory provided altitude and azimuth positions for the sun at Providence, Rhode Island. This information was converted to orthogonal measure then mapped into orthographic drawings of the four vertical faces of the sunbox. These tracings formed the basis for the sciagraphic openings, which were enlarged at intervals of 0.5 degrees, equaling approximately 5 minutes of observed sun movement. The resulting drawings served as templates for cutting openings in the sunbox.

The geometric construction was thus fundamentally an intersection of a series of cones—or sunpaths—with an orthogonal form. Although arbitrary in some respects, the box’s proportions were determined by the extent of observed solar passage over one year. In plan, the angles of the diagonals of the box derived from the limits of the sun’s yearly movement, the solstices. The height of the enclosure was determined by the highest trajectory of light as it crosses the corners. The surfaces of the sunbox therefore became a record of sunlight, a series of sections through the cones that describe the sun’s movement in the sky. The cones themselves change over the course of a year: concave around June, convex during the winter months. The curves that describe the arc of the sun’s path against the sunbox walls are all parabolas that manifest in curious “draping” forms as they intersect the corners of the box.

Like its time-keeping precedents, the sunbox functioned only on sunny days and measured time locally. The insertion of photosensitive paper on the floor of the sunbox opened up a new capacity. Sepia paper, which was changed daily for three years, recorded a full day of light streaks; in series, these tracings recorded changes of seasons, the curvature of the earth and weather patterns. The resulting film brought into view an ebb and flow of solar time uncannily like breathing: a rhythmical rise and fall of time and light, unevenly flickering as weather passed, slowing to pause at the solstice then accelerating to a peak at the equinox.

Light as Place

When the project started, its focal point was both literally and figuratively the center of the floor of the sunbox. All projections were calibrated around that interior point. Context or place was present only in the abstract: the unique sun path information of Providence. With grants from the State of Rhode Island and the City of Providence, the sunbox was reconceived to become a public and site-specific construct.

Two design changes transformed the first sunbox into a public work. The first stemmed from the discovery that if this first sunbox were turned upside-down, and the marker at the center of its floor—now at the ceiling—turned into an oculus, the sun’s light could be projected through this oculus to points outside its enclosure. Sunlight could thus be made to fall back out through apertures onto markers on the exterior ground. This inversion would visually root the apparatus to its immediate site, making sunlight/time externally visible. The second sunbox design superimposed this new inverted scheme onto that of the original construction. Now, as one set of light rays passed through the new sunbox via the oculus and out onto the ground outside, another set of light rays would enter through an aperture on the side of the enclosure to fall onto the center of the chamber. The sun and, by implication, time could be marked on the interior as well as the exterior of the sunbox. The second change was to rebuild the sunbox large enough so passers-by in a public park could experience it spatially, at “full” scale.

The new construct was located at a site in Roger Williams Park where the tree line was at its most consistent angular height all around, about 12 to 18 degrees above the horizon from east through south to west, minimizing the number of shadows cast onto the site. The depth and angular opening of the oculus were determined by this condition while the proportions and shape of the original sunbox were kept, each wall being determined by the sun’s movement at the site.

Light as Construction

Constructing a sundial brings two worlds together: celestial geometries intersect terrestrial, material conditions. The primary goal of the second sunbox was to translate celestial data into tectonic and constructive strategies, to make a construction of sunlight from a “drawing” of the sun’s motion. A tectonic order developed in such a way can mediate abstract geometry (projected planes, lines, and angles) and the constructed thickness of materials. In the development of the sunbox project, media and medium conflate, so that drawing becomes construction.

The first architectural decision derived from a constructional intent to tie the projective logic of the sun’s path to tectonic concerns. In place of a solid box in which openings are cut, and in the interest of greater transparency between inside and outside, a system of vertical and horizontal fins addressed both structural and sciagraphic demands. This system was generated by extending the edges of each solar opening horizontally and vertically until it crossed the edges of adjacent openings to form a network. Once the network was established, the depth of each fin was refined to mask sunlight, following the discovery that the generated openings operated, in effect, like two pairs of light-channeling edges. Light falling from the oculus to the outside would first encounter the horizontal and vertical edge closest to the oculus, then fall onto the vertical and horizontal edges farthest from the oculus. Therefore, each fin—horizontal or vertical—could grow in depth and not affect the effective size of their respective openings (their sciagraphic attributes) as long as the edges that formed the opening were not altered. As these fins grew away from their assigned edges, they were able to mask adjacent areas that had to remain opaque to sunlight but transparent to the view. By adjusting fin depths, two openings could overlap in elevation yet remain autonomous operationally. Materiality and thickness thus introduced sciagraphic properties that in turn opened up opportunities for articulating architectural qualities.


The construction of the sunbox is mute. It represents nothing, the consequence of being a register. What then is its value? Although conceived as an instrument like other sundials, in its final expression it brings to visibility the movement of the sun specific to locale. Instruments are tools, but the sunbox is hardly useful for our contemporary chronometric needs. Its value is more like that of a photograph than a camera. This fusion of light and time requires no translation or reading of a dial. The sheer number of people who gathered during the sunbox’s installation to witness light falling through onto its markers—making an event of something that has become inconsequential—suggests that forgotten relations between earth and sky, and light and time, may still have a place in architectural work.

Chris Bardt, Principal