scipy.spatial.transform.Rotation.as_rotvec

Rotation.as_rotvec()

Represent as rotation vectors.

A rotation vector is a 3 dimensional vector which is co-directional to the axis of rotation and whose norm gives the angle of rotation (in radians) [1].

Returns

rotvecndarray, shape (3,) or (N, 3)

Shape depends on shape of inputs used for initialization.

References

1(1,2)

https://en.wikipedia.org/wiki/Axis%E2%80%93angle_representation#Rotation_vector

Examples

>>> from scipy.spatial.transform import Rotation as R

Represent a single rotation:

>>> r = R.from_euler('z', 90, degrees=True)
>>> r.as_rotvec()
array([0.        , 0.        , 1.57079633])
>>> r.as_rotvec().shape
(3,)

Represent a stack with a single rotation:

>>> r = R.from_quat([[0, 0, 1, 1]])
>>> r.as_rotvec()
array([[0.        , 0.        , 1.57079633]])
>>> r.as_rotvec().shape
(1, 3)

Represent multiple rotations in a single object:

>>> r = R.from_quat([[0, 0, 1, 1], [1, 1, 0, 1]])
>>> r.as_rotvec()
array([[0.        , 0.        , 1.57079633],
       [1.35102172, 1.35102172, 0.        ]])
>>> r.as_rotvec().shape
(2, 3)