Chasles' theorem (kinematics)

Every rigid motion is a screw displacement

In kinematics, Chasles' theorem, or Mozzi–Chasles' theorem, says that the most general rigid body displacement can be produced by a screw displacement or screw motion. A direct Euclidean isometry in three dimensions involves a translation and a rotation. The screw displacement representation of the isometry decomposes the translation into two components, one parallel to the axis of rotation associated with the isometry and the other component perpendicular to that axis.

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