axis_angle_from_quaternion

compas.geometry.axis_angle_from_quaternion(q)

Returns an axis and an angle of rotation from the given quaternion.

Parameters:

q[float, float, float, float]

Quaternion as a list of four real values [qw, qx, qy, qz].

Returns:

axis[float, float, float]

XYZ coordinates of the rotation axis vector.

anglefloat

Angle of rotation in radians.

Examples

>>> q = [1., 1., 0., 0.]
>>> axis, angle = axis_angle_from_quaternion(q)
>>> allclose(axis, [1., 0., 0.])
True
>>> allclose([angle], [math.pi/2], 1e-6)
True