Adrian Bejan | Perspective Drawing, from Design in Nature

In this lecture, Adrian Bejan connects the invisible reality of flow, such as heat transfer through solids, with the visible logic of drawing. He begins with the flow of heat in electronics, driven by temperature differences, and illustrates how these unseen structures are represented through drawing. Bejan uses sketches not simply for visualization but as a way of teaching design, blending geometry with the logic of flow architecture. Drawing becomes a way to express how flow moves through systems, and how it should be shaped for efficiency. He shows how visual techniques, if misused, distort physical understanding, and how correct drawing reveals the true nature of flow.

• He warns against the mistake of using parallel lines in drawings, explaining that they mislead the viewer by making the object appear to grow wider with distance.

• He explains that the correct way is to use tapered lines that intersect at a point far away, called the horizon. This approach is known as perspective, which is the key to making a drawing look realistic.

• Bejan notes that even software users often fall into the trap of parallelism, forgetting that lines must appear to converge to represent three-dimensional form correctly.

• He refers to paintings before the Renaissance, which lacked perspective and therefore appeared unnatural. These are contrasted with Renaissance breakthroughs.

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Umit Gunes, Ph.D.
Assoc. Prof., Yildiz Technical University
umitgunes.com