outofplane

Out of plane, often written as out-of-plane or outofplane, is a term used to describe a quantity, point, or feature that does not lie in a specified reference plane. In three-dimensional space, a plane is defined by a set of points satisfying a linear equation; a point is in-plane if it satisfies the plane equation, and is out-of-plane otherwise. The concept contrasts with in-plane, which lies within the reference plane.

In geometry and kinematics, out-of-plane elements are described relative to a plane of reference. For example, an out-of-plane rotation refers to rotation about an axis perpendicular to the plane, and out-of-plane displacement refers to movement perpendicular to the plane.

In computer graphics and engineering, out-of-plane describes components, deformations, or motions that extend out of the projection or reference plane. In materials science and crystallography, out-of-plane deformation or vibrations occur perpendicular to a layered structure or surface; in graphene and thin films, out-of-plane distortions influence mechanical and electronic properties.

In optics and imaging, an out-of-plane tilt or misalignment indicates a component of tilt or angular error perpendicular to the intended plane of incidence or imaging plane. In geology and structural geology, beds or layers that tilt away from a horizontal reference plane are described as out-of-plane.

See also: in-plane, projection, normal vector, plane.