Architectural drawings play a crucial role in the representation of technical information necessary for constructing buildings. Technical drawings are those that communicate information related to the design and construction of physical objects, buildings, and environments. These drawings are known as technical drawings, and a set of technical drawings and other related information, such as schedules, used in the design and construction of a building are collectively called construction documents.

Technical drawings are scaled and proportionally accurate to the physical reality of the object, architecture, landscape, or urban design project they represent. Precision and accuracy are essential in technical drawing, which historically was achieved by hand drafting. Hand drafting involves drawing with tools such as straight edges, triangles, and compasses that allow for precise control in drawing geometry and linework that can be measured. Additional tools, such as French curves, were developed to aid in drafting curve geometry, providing a means of accurately drawing smooth continuous curves.

In the historical process of wooden ship building, ribs and keels, the elements that form the transverse and longitudinal structural framework of boats, were fabricated by drawing long, smooth curves onto timber, which were then cut to shape. Drawing the curve geometry required a template consisting of long, flexible strips of wood or steel, called splines, that were defined and held in position by weights. These tools and techniques served as a method for drawing the curve on large sheets of timber at a scale of 1:1, and eventually on paper. While most contemporary boat design processes rely on digital methods for the production of technical drawings, the artform of hand-drafting splines is still in use today.

In the realm of computer-aided design (CAD) systems, the term spline is derived from the traditional term and is the basis for creating curve geometries in digital drafting and modeling environments. CAD systems have revolutionized the technical drawing process, providing faster and more accurate ways of creating technical drawings. These systems utilize digital platforms that facilitate the process of creating technical drawings, eventually leading to the replacement of hand drafting with computer-aided drafting. The majority of architectural practices today rely on CAD tools to create design drawings and technical drawings, thanks to their ability to generate technical drawings faster, more accurately, and with fewer errors.

Bronze spline weights, Edson International, New Bedford, MA.

Figure 1.16. Eero Saarinen and Associates, Trans World Airlines Terminal Building, New York, NY. c.1956. Photograph of the curved column and roof. Eero Saarinen collection, 1880–2004 (inclusive), 1938–1962 (bulk). Manuscripts & Archives, Yale University Library. Photo: Richard Knight.

Figure 1.17. Eero Saarinen and Associates, Trans World Airlines Building Terminal, New York, NY. c.1956. As-builts, plan for the curved front column. Eero Saarinen collection, 1880–2004 (inclusive), 1938–1962 (bulk). Manuscripts & Archives, Yale University Library.

Félix Candela, Plan and elevation projection drawings of hyperbolic paraboloid surfaces. © Avery Architectural & Fine Arts Library, Columbia University.

Félix Candela, Los Manantiales Restaurant, Xochimilco, Mexico City, Mexico, 1958. Drawing of the roof geometry.