`scipy.spatial.transform._rotation:Rotation.from_rotvec`

Signature

staticmethoddef from_rotvec(rotvec: ArrayLike, degrees: bool = False) → Rotation

Initialize from 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].

rotvec : array_like, shape (..., 3): A single vector or an ND array of vectors, where the last dimension contains the rotation vectors.
degrees : bool, optional: If True, then the given magnitudes are assumed to be in degrees. Default is False.
versionadded 1.7.0

rotation : `Rotation` instance: Object containing the rotations represented by input rotation vectors.

from scipy.spatial.transform import Rotation as R
import numpy as np

✓

Initialize a single rotation:

r = R.from_rotvec(np.pi/2 * np.array([0, 0, 1]))

✓

r.as_rotvec()

✗

array([0.    , 0.    , 1.5708])

r.as_rotvec().shape

✓

(3,)

Initialize a rotation in degrees, and view it in degrees:

r = R.from_rotvec(45 * np.array([0, 1, 0]), degrees=True)
r.as_rotvec(degrees=True)

✓

array([ 0., 45.,  0.])

Initialize multiple rotations in one object:

r = R.from_rotvec([
[0, 0, np.pi/2],
[np.pi/2, 0, 0]])

✓

r.as_rotvec()

✗

array([[0.    , 0.    , 1.5708],
       [1.5708, 0.    , 0.    ]])

r.as_rotvec().shape

✓

(2, 3)

It is also possible to have a stack of a single rotation:

r = R.from_rotvec([[0, 0, np.pi/2]])
r.as_rotvec().shape

✓

(1, 3)