Offcenterline

Offcenterline is a term used to describe a line or axis that is displaced laterally from the reference centerline of an object or system. The centerline serves as the primary axis for symmetry, measurement, and assembly, and the offcenterline marks features that are not located on that axis.

An offcenterline can be intentional, such as when holes, slots, seams, or attachment points need to be offset to accommodate components, provide clearance, or influence weight distribution. It can also be the result of manufacturing tolerances, deformation, or misalignment, in which case it is considered an undesirable deviation relative to the nominal geometry. In computer-aided design and drafting, an offcenterline is typically represented as a line parallel to the centerline at a specified offset distance.

In practice, offcenterline configurations appear in many domains. In piping and ductwork, connections may be offset from the pipe or duct axis to avoid clashes with supports or other hardware. In mechanical design, components mounted along the offcenterline can help balance loads or fit within tight packaging envelopes. In aerospace and automotive contexts, offset features influence aerodynamics, control surface geometry, and payload placement.

Measurement of an offcenterline is usually described by the offset distance from the centerline, with tolerances defining allowable variation. If the offset varies along the length, the term may be supplemented with direction or curvature descriptors.

See also: centerline, offset, eccentricity, alignment, asymmetry.