scipy.spatial.transform.Rotation.from_rotvec

classmethod Rotation.from_rotvec(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 (in radians) [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.

Returns

rotationRotation instance

Object containing the rotations represented by input rotation vectors.

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

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 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)