def from_angle_direction_plane(cls, angle, direction, plane):
"""
Parameters
----------
angle : :obj:`float`
The angle in radians.
direction : compas.geometry.Vector or :obj:`list` of :obj:`float`
The direction vector as list of 3 numbers.
It must be orthogonal to the normal vector (i.e. it must lie in the shear plane).
plane : compas.geometry.Plane or (point, normal)
The shear plane defined by a point and normal.
Raises
------
ValueError
If the shear direction does not lie in the shear plane.
Returns
-------
Shear
The shear transformation object.
Examples
--------
>>> from compas.geometry import cross_vectors
>>> angle = 0.1
>>> direction = [0.1, 0.2, 0.3]
>>> point = [4, 3, 1]
>>> normal = cross_vectors(direction, [1, 0.3, -0.1])
>>> S = Shear.from_angle_direction_plane(angle, direction, (point, normal))
"""
point, normal = plane
return cls(matrix_from_shear(angle, direction, point, normal))
def __init__(self,
angle=0.,
direction=[1, 0, 0],
point=[1, 1, 1],
normal=[0, 0, 1]):
self.matrix = matrix_from_shear(angle, direction, point, normal)
def from_angle_direction_plane(cls, angle, direction, plane):
"""Construct a shear transformation from an angle, direction and plane.
Parameters
----------
angle : float
The angle in radians.
direction : [float, float, float] | :class:`compas.geometry.Vector`
The direction vector as list of 3 numbers.
It must be orthogonal to the normal vector (i.e. it must lie in the shear plane).
plane : [point, vector] | :class:`compas.geometry.Plane`
The shear plane defined by a point and normal.
Returns
-------
:class:`compas.geometry.Shear`
The shear transformation object.
Raises
------
ValueError
If the shear direction does not lie in the shear plane.
Examples
--------
>>> from compas.geometry import cross_vectors
>>> angle = 0.1
>>> direction = [0.1, 0.2, 0.3]
>>> point = [4, 3, 1]
>>> normal = cross_vectors(direction, [1, 0.3, -0.1])
>>> S = Shear.from_angle_direction_plane(angle, direction, (point, normal))
"""
point, normal = plane
return cls(matrix_from_shear(angle, direction, point, normal))
def test_matrix_from_shear():
angle = 0.1
direction = [0.1, 0.2, 0.3]
point = [4, 3, 1]
normal = cross_vectors(direction, [1, 0.3, -0.1])
S = matrix_from_shear(angle, direction, point, normal)
s = [[0.992033620789569, 0.02245070504757821, -0.012311676961575148, -0.023174921339435575], [-0.015932758420861955, 1.0449014100951564, -0.024623353923150296, -0.04634984267887115], [-0.023899137631292932, 0.06735211514273462, 0.9630649691152746, -0.0695247640183067], [0.0, 0.0, 0.0, 1.0]]
assert np.allclose(S, s)