scipy.spatial.transform.Rotation.from_rotvec

Rotation.from_rotvec()

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].

Parameters

rotvecarray_like, shape (N, 3) or (3,)

A single vector or a stack of vectors, where rot_vec[i] gives the ith rotation vector.

degreesbool, optional

If True, then the given magnitudes are assumed to be in degrees. Default is False.

New in version 1.7.0.

Returns

rotationRotation instance

Object containing the rotations represented by input rotation vectors.

References

1

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

Examples

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

Initialize a single rotation:

>>> r = R.from_rotvec(np.pi/2 * np.array([0, 0, 1]))
>>> r.as_rotvec()
array([0.        , 0.        , 1.57079633])
>>> 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.        , 1.57079633],
       [1.57079633, 0.        , 0.        ]])
>>> r.as_rotvec().shape
(2, 3)

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

>>> r = R.from_rotvec([[0, 0, np.pi/2]])
>>> r.as_rotvec().shape
(1, 3)