A circle is defined by a point rotating about another point at a fixed distance, and can be precisely described by most the elementary of mechanical drafting tools, a compass. This simplicity allows for it to be easily dismissed, within the complexities of contemporary digital work in which a wide variety of curves can be described through software built-in computational processes. However, it is exactly the simplicity of the circle that enabled architects to use it to engender wide variety of complex forms in the history of architectural drawing. As Robin Evans has pointed out, the orthographic deformations of a circle remain “commensurable” through the direct relationship with a measurable source figure. Circular deformation through orthographic projection allowed for the generation of numerous related and yet “nameless” curvatures whose linear connection to the circle allowed them to be both measured and built. What Evans did not point out, what was in fact central to the construction of drawings of vaults with cross sectional profiles of “nameless” curvature, was a practice that had much more to do with computation than it did with representation. This practice, as studied in the following work, offers a historical counterpoint to the role of both curvature and computation in contemporary practice.