class ShapeProps(object):
"""
Base class for shape properties.
"""
def __init__(self):
self._props = GProp_GProps()
@property
def mass(self):
"""
:return: The mass of the shape. This corresponds to total length for
linear properties, total area for surface properties, or total
volume for volume properties.
:rtype: float
"""
return self._props.Mass()
@property
def cg(self):
"""
:return: The center of gravity.
:rtype: afem.geometry.entities.Point
"""
gp_pnt = self._props.CentreOfMass()
return Point(gp_pnt.X(), gp_pnt.Y(), gp_pnt.Z())
@property
def static_moments(self):
"""
:return: The static moments of inertia Ix, Iy, and Iz.
:rtype: tuple(float)
"""
return self._props.StaticMoments(0., 0., 0.)
@property
def matrix_of_inertia(self):
"""
:return: The 3 x 3 matrix of inertia.
:rtype: numpy.ndarray
"""
gp_mat = self._props.MatrixOfInertia()
matrix = []
for j in range(1, 4):
row = []
for i in range(1, 4):
row.append(gp_mat.Value(i, j))
matrix.append(row)
return array(matrix, dtype=float)
def moment_of_inertia(self, axis):
"""
Compute the moment of inertia about the axis.
:param afem.geometry.entities.Axis1 axis: The axis.
:return: The moment of inertia.
:rtype: float
"""
return self._props.MomentOfInertia(axis)
def on_select(shapes):
"""
Parameters
----------
shape : TopoDS_Shape
"""
g1 = GProp_GProps()
for shape in shapes:
brepgprop_LinearProperties(shape, g1)
mass = g1.Mass()
centre_of_mass = g1.CentreOfMass()
com_x = centre_of_mass.X()
com_y = centre_of_mass.Y()
com_z = centre_of_mass.Z()
static_moments = g1.StaticMoments()
print("shape {shape}: \n mass: {mass}"
"\n center of mass: {com_x}, {com_y}, {com_z}"
"\n static moments: {static_moments}".format(**vars()))