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 = [1.0, 1.0, 0.0, 0.0]
>>> axis, angle = axis_angle_from_quaternion(q)
>>> allclose(axis, [1.0, 0.0, 0.0])
True
>>> allclose([angle], [math.pi / 2], 1e-6)
True