Rabattement (drafting)
Rabattement is a rotation of a planar object around a folding line in order to align the object with another plane. Rabattement is used in technical drawings to produce developments. In these drawings the object is "unfolded" to lay flat on a plane so it can be represented in entirety. The term originates, due to the typical alignment plane being the horizontal one, although a vertical plane is sometimes used in elevation.
The technique of rabattement is very old: the archaic paintings that predate Antiquity used similar methods to achieve "intellectual realism" by unfolding the object to represent its hidden sides.
Rabattement was extensively used by stonemasons in the construction drawings, and, together with projection plane, evolved into a method of descriptive geometry. Descriptive geometry manuals sometimes use the term "rotation" when discussing moving points and lines, reserving "rabattement" for shapes and planes, but in practice both operations are identical.
The goal of the rabattement operation is to represent the true shape and size of a face of an object.