Curves and Surfaces for CAGD, 5th Edition

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P. Bézier

How a Simple System Was Born

In order to solve CAD/CAM mathematical problems, many solutions have been offered, each adapted to specific matters. Most of the systems have been invented by mathematicians, but UNISURF was developed by mechanical engineers from the automotive industry who were familiar with parts mainly described by lines and circles. Fillets and other blending auxiliary surfaces were scantly defined; their final shape was left to the skill and experience of patternmakers and die-setters.

Around 1960, designers of stamped parts, that is, car-body panels, used french curves and sweeps, but in fact, the final standard was the “master model,” the shape of which, for many valid reasons, could not coincide with the curves ...