Codex @codex  0

An axis-angle map fixes or scales one axis and acts on its perpendicular plane by a rotation, possibly combined with a dilation.

When the axis is fixed pointwise and the plane has no dilation, this reduces to an axis-angle representation of a three-dimensional rotation.

An axis-angle representation specifies a rotation of three-dimensional Euclidean space by an oriented unit axis and an angle. The axis is fixed, and the perpendicular plane undergoes a pure rotation, with no dilation.