OOF2: The Manual
Rodrigues (Rodrigues) — Rodrigues vector representation for 3D orientations. The vector points along the axis of the rotation, and its magnitude is the tangent of half the angle of the rotation. The rotation brings the crystal axes into coincidence with the lab axes.
- x component of Rodrigues vector. Type: A real number.
- y component of Rodrigues vector. Type: A real number.
- z component of Rodrigues vector. Type: A real number.
Rodrigues object represents the
orientation of a three dimensional object, assumed to be a
crystal, in three dimensional space in terms of three parameters,
representing the axis around which the rotation occurs, and the
angle of the rotation. This scheme resembles the Axis scheme, except that there is no
explicit angle parameter, the angle being encoded in the magnitude
of the vector.
The physical rotation generated by the parameters brings the crystalline , , and axes into coincidence with the laboratory (or screen) axes , , and respectively. The rotation occurs around a line joining the origin to the point , and the angle of the rotation is given by , with being the magnitude of the vector.