French Curves CKS FC-01 Ruler

A French curve is a template usually made from metal, wood or plastic composed of many different segments of the Euler spiral (aka the clothoid curve). It is used in manual drafting and in fashion design to draw smooth curves of varying radii. The curve is placed on the drawing material, and a pencil, knife or other implement is traced around its curves to produce the desired result. They were invented by the German mathematician Ludwig Burmester and are also known as Burmester (curve) set.

French curve physical templates are regularly used for original high fashion design and by home sewists (along with other types of artisans) most usefully in necklines, sleeve, bust and waist variations. The varied curve radii allow for smooth and stylish personalized adjustments of standard purchased clothing patterns for an excellent, personalized fit. Fashion designers and sewists may use a selection of french curves, hip curves, straight edges and L-shaped right angle rulers. They may be in metal or clear plastics, with measurements marked in metric or imperial.