Sleutelvlak

Sleutelvlak translates to "key plane" and is used in Dutch to refer to a plane that functions as a key reference within a geometric, architectural, or modelling context. It is not a standardized term with a single formal definition in Dutch mathematical vocabulary; its precise meaning depends on discipline and author.

In mathematics and geometry, a sleutelvlak may be the reference plane from which a 3D coordinate system is defined, or a plane that contains a key curve or feature that determines the arrangement of other elements. It can also denote a plane of projection in descriptive geometry.

In applied fields such as computer-aided design (CAD), engineering design, or computer graphics, sleutelvlak is often used to indicate the main work plane from which sketches are created and features are aligned to others.

Etymology: The term combines sleutel (key) and vlak (plane), reflecting its role as a central reference surface in a construction or analysis.

See also: plane; reference plane; projection plane; principal plane.