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].

Parameters

degreesboolean, optional

Returned magnitudes are in degrees if this flag is True, else they are in radians. Default is False.

New in version 1.7.0.

Returns

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

Shape depends on shape of inputs used for initialization.

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)