copyright: Ralph L. Knowles, 2008

Solar Aesthetic


Ralph L. Knowles

Professor Emeritus

USC School of Architecture

A design research project graphs the effects of sunlight and gravity in three dimensions.


Key Words: aesthetic, architecture, daylight, energy, nature, solar.

What are the aesthetic implications of designing with nature? This question is being asked with growing insistence as architects explore the need to conserve energy. At this critical time of energy use and worldwide urbanization, architects are being challenged by such leaders in the field as Edward Mazria who has called for “a dialogue with nature” to answer the problem. This paper explores some possible outcomes of such a dialogue.

What might buildings look like if we accepted the challenge to have open and honest cooperation with nature? What patterns would they display? Would we meet them with recognition and empathy or pass them by with indifference? Would they interest us, please us and bring us joy, or would they be ordinary and lacking in quality? These are aesthetic questions but with practical meaning for a sustainable life.

Given the awakening interest in a new architectural aesthetic, a design research project initiated in 1962 takes on fresh meaning today. The research carried out at Auburn University and supported by the Graham Foundation, was concerned with illustrating the force effects of natural phenomena, specifically sunlight and gravity, on form. These forces are clearly reflected in the growth and patterns of nature. The sunny sides of slopes exhibit different plants and animals than shady slopes. Natural structures, such as sand dunes, reflect the forces of wind and gravity. Buildings are subject to the same natural forces that have caused differentiation in nature, but rarely acknowledge them in built form.

A new architectural aesthetic was not the purpose of the 1962 work, rather it was to test a proposition: A building made in balanced response to natural forces will exhibit differentiation useful for crucial legibility in the city setting. The idea of urban legibility came from an earlier reading of Kevin Lynch’s influential book, The Image of the City, in which he asserts the importance of providing vital cues for successful orientation and free movement. The Auburn study tested my belief that the essential clarity and legibility Lynch sought was to be found in designing with nature.

The study began with no prior idea of resulting form. In fact, throughout the study, novel shapes and structures seemed to emerge as if by a self-organizing process of natural growth and transformation, not by design. As it turned out, preconceptions of form would very likely have been wrong and would have surely gotten in the way of the work.

The Auburn study, simply in order to facilitate a beginning point, a reference for graphing the different effects of natural forces, selected five basic geometric forms with a range of surface configurations and orientations: a cube, an ellipsoid, a tetrahedron, a prism and a hyperboloid of revolution.While not actual building forms, their geometry provided an architectural idiom for analysis. (A later study, made at the University of Southern California, did not begin with selected geometric forms as a reference for graphing force effect. Instead, it generated forms to satisfy specified performance by using sun machines, water tables and wind tunnels.)

The Auburn study progressed in several phases. The first phase graphed the impact of sunlight on form, the second graphed gravity, and the third, the combined forces of sunlight and gravity. The fourth phase sought to apply the concept of form differentiation to a simple program for an office building. The study, though limited to an examination of only two natural forces and completed almost 50 years ago, evokes images of differentiated form that we can identify with and understand today.



sun_01 sun_02 sun_03

A technique for graphing the varied effects of sunlight uses a system of projecting planes to shield the basic form during prescribed hours, a technique applicable to daylight design. Planar generations are derived from the geometry of the basic reference form. The resulting graphs have both static and dynamic components. The planes are themselves static, but the forces they respond to are dynamic and change the graph’s aspect by day and season. The results are asymmetrical, horizontally differentiated graphs for a 30-degree north latitude location. (Color is used to delineate forms, not to indicate actual directions of sunlight.)




The gravity studies use a similar graphing technique of projecting planes. Hypothetical floor loads are applied regularly to the surface of each form in such a way that they affect each point at the same elevation equally. But unlike the sun graphs that tend to be horizontally differentiated in response to orientation, the gravity graphs are mostly symmetrical and vertically differentiated in response to accumulating loads. The gravity graphs also lack the dynamic component of the sun.



Although there may be a hierarchy of force action, buildings are rarely affected by a single force. Sun and gravity graphs are therefore combined to form a complex of double-acting planes describing simultaneous but differently acting forces. Both the number and dimension of planes become adjustable graphing elements. Accordingly, longer or more numerous planes indicate greater force effects. In an ideal solution, each plane acts simultaneously to provide for sun control and gravity loads. But the more usual case in the study is where only a portion of any plane is double acting, with either sun or gravity dominating the remainder. Graphs are compared based on their different percentages of double-acting plane.



The last phase of the study applies an understanding of form differentiation that comes out of the sun-gravity studies, to the design of an office building. The building program calls for public spaces at the top and street levels, with smaller private spaces in between. Unlike the previous phases of study in which planes are presumed to have only length and breadth but no thickness, this phase assumes a concrete structural system in which thickness and material strength are varied as well as plane dimensions. The study looks at only the building’s outer support system and not at either interior spaces or services.

The implications of this work for architectural and urban design are now being rediscovered. The concept of a building as an ecological form, differentiated in response to natural forces, points to a new aesthetic. The result will not be distinguished by a common expression of form, as was Modernism, made possible by massive injections of energy that isolate people from natural clues. Instead, varied patterns and forms that engage our inherent capacity to feel the diversity of nature will characterize this new aesthetic.


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Professor William H. Turner and the students of the 1962-63 fourth year design class of Auburn University School of Architecture, here listed by geometric form.

Cube: Boutwell, C.A.; Brown, W.W.; Freeman, R.M.; Oldham, G.H.; Smith, J.M.; Snook, C.J.

Ellipsoid: Bowden, J.W.; Carrera, J.I.; Hill, H.S.; Knodel, B.D.; Leeger, L.M.; Richmond, W.L.

Hyperboloid of Revolution: Cugowski, R.M.; Love, B.F.; Todd, S.B.; Williams, J.B.; Woodfin, C.D.

Prism: Acton, S.P.; Ballard, J.H.; Binkley, A.L.; Brady, J.H.R.; Colman, J.K.J.; Meador, D.L.

Tetrahedron: Biggers, R.R.; Coykendall, J.B.; Egger, D.E.; Hagler, B.L.; Regan, J.T.; Savage, W.T.