def from_quaternion(cls, quaternion, point=[0, 0, 0]):
"""Construct a frame from a rotation represented by quaternion coefficients.
Parameters
----------
quaternion : list of float
Four numbers that represent the four coefficient values of a quaternion.
point : list of float, optional
The point of the frame.
Defaults to [0, 0, 0].
Returns
-------
:class:`compas.geometry.Frame`
The constructed frame.
Examples
--------
>>> q1 = [0.945, -0.021, -0.125, 0.303]
>>> f = Frame.from_quaternion(q1, point=[1., 1., 1.])
>>> q2 = f.quaternion
>>> allclose(q1, q2, tol=1e-03)
True
"""
R = matrix_from_quaternion(quaternion)
xaxis, yaxis = basis_vectors_from_matrix(R)
return cls(point, xaxis, yaxis)
def test_matrix_from_quaternion():
q1 = [0.945, -0.021, -0.125, 0.303]
R = matrix_from_quaternion(q1)
r = [[0.7853252073134178, -0.5669097811969227, -0.2487521230892197, 0.0],
[0.5774003396942752, 0.8156659006893796, -0.0360275751823359, 0.0],
[0.22332300929163754, -0.11533619742231993, 0.9678968927964832, 0.0],
[0.0, 0.0, 0.0, 1.0]]
assert allclose(R, r)
def get_matrix_from_trs(self, node):
matrix = identity_matrix(4)
if 'translation' in node:
translation = matrix_from_translation(node['translation'])
matrix = multiply_matrices(matrix, translation)
if 'rotation' in node:
rotation = matrix_from_quaternion(node['rotation'])
matrix = multiply_matrices(matrix, rotation)
if 'scale' in node:
scale = matrix_from_scale_factors(node['scale'])
matrix = multiply_matrices(matrix, scale)
return matrix
def get_matrix_from_trs(self):
"""If the node's displacement from the origin is given by its translation, rotation and
scale attributes, this method returns the matrix given by the composition of these
attributes.
Returns
-------
"""
matrix = identity_matrix(4)
if self.translation:
translation = matrix_from_translation(self.translation)
matrix = multiply_matrices(matrix, translation)
if self.rotation:
rotation = matrix_from_quaternion(self.rotation)
matrix = multiply_matrices(matrix, rotation)
if self.scale:
scale = matrix_from_scale_factors(self.scale)
matrix = multiply_matrices(matrix, scale)
return matrix
def test_quaternion_from_matrix():
q1 = [0.945, -0.021, -0.125, 0.303]
R = matrix_from_quaternion(q1)
q2 = quaternion_from_matrix(R)
assert allclose(q1, q2, tol=1e-03)
