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 [1].

Returns

rotvecndarray, shape (3,) or (N, 3): Shape depends on shape of inputs used for initialization.
degreesboolean, optional: Returned magnitudes are in degrees if this flag is True, else they are in radians. Default is False.

References

1: 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 rotation in degrees:

>>> r = R.from_euler('YX', (-90, -90), degrees=True)
>>> s = r.as_rotvec(degrees=True)
>>> s
array([-69.2820323, -69.2820323, -69.2820323])
>>> np.linalg.norm(s)
120.00000000000001

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)