zretning

Zretning is a term used in some Scandinavian language contexts to denote the z-direction in a three-dimensional Cartesian coordinate system. It typically refers to depth: movement or orientation along the axis perpendicular to the x- and y-axes. In common usage, a positive z value indicates a step in the positive z direction, while a negative value indicates a step in the opposite direction.

In mathematics and physics, the z-axis is one of the three principal axes. The orientation of the z-axis is defined together with the x- and y-axes, and in a right-handed coordinate system the cross product of the x- and y-axes points in the direction of the positive z-axis. The exact orientation (which way is positive) is a matter of convention and depends on the chosen coordinate system.

In computer graphics and 3D modeling, z-retning is especially important for depth handling. Depth buffering, perspective projection, and camera placement all rely on consistent z-values to render scenes correctly. Different graphics APIs adopt different conventions for the z-axis; for example, OpenGL and DirectX historically use different handedness and forward directions, so developers must adjust transformations accordingly.

Usage notes: the term is more common in Danish or Norwegian technical documentation and may be expressed as z-axis or z-direction in English. It is generally interchangeable with references to depth or forward/backward movement along the depth axis, depending on the context. See also: z-axis, Cartesian coordinate system, depth buffering.