Signed distance functions (SDFs) as instruments of geometric modeling have become important only recently. They were known for ages, but mostly in academic circles. Boundary representations and images, which we’ll look into in the following chapters, were the main techniques for modeling in computer-aided design (CAD), medical imaging, and games. Now the tables are turning.
The driving force behind the prominence of SDFs is 3D printing. With a printer, you can easily produce forms so complex that chiseling them with milling tools would have been unheard of only a few decades ago. With SDFs, you can program these complex forms to follow the properties you desire. You can “program” the material to hold stress, dissipate heat, or even merge with a living tissue properly, all by programming an SDF behind the produced body (figure 10.1).
Figure 10.1 This femur model, generated from an SDF, is specifically made to be porous. Porosity is important so that implants can grow properly into living tissue.
