def test_surfacic_weight():
shell = BRepPrimAPI_MakeBox(10, 10, 10).Shell()
# Cad is defined in m
w = Mass.from_surface_surfacic(surfacic_mass_kg_per_m2=1, surface=shell, cad_unit='m').mass_kg
assert 600 - 1e-6 <= w <= 600 + 1e-6
# Cad is defined in mm
w = Mass.from_surface_surfacic(surfacic_mass_kg_per_m2=1, surface=shell, cad_unit='mm').mass_kg
assert 600*1e-6 - 1e-12 <= w <= 600*1e-6 + 1e-12
def test_total_mass():
w1 = Mass.from_position_m(10, PositionM(2, 3, 4))
w2 = Mass.from_position_m(10, PositionM(2, 3, 4))
w3 = Mass.from_position_m(15, PositionM(2, 3, 4))
masses = MassesCollection()
masses.add_mass(w1)
masses.add_mass(w2)
masses.add_mass(w3)
assert masses.mass_kg == 35
def test_cg():
w1 = Mass.from_position_m(10, PositionM(2, 5, 20))
w2 = Mass.from_position_m(10, PositionM(10, 5, 30))
masses = MassesCollection()
masses.add_mass(w1)
masses.add_mass(w2)
assert masses.mass_kg == 20
assert masses.cg_m.x == 6
assert masses.cg_m.y == 5
assert masses.cg_m.z == 25
def test_total_weight():
w1 = Mass.from_position_m(10, PositionM(2, 3, 4))
w2 = Mass.from_position_m(10, PositionM(2, 3, 4))
w3 = Mass.from_position_m(15, PositionM(2, 3, 4))
masses = MassesCollection()
masses.add_mass(w1)
masses.add_mass(w2)
masses.add_mass(w3)
expected_value = 343.23274999999995
tol = 1e-9
assert expected_value - tol <= masses.weight_N <= expected_value + tol
def test_find_corrector():
w1 = Mass.from_position_m(10, PositionM(10, 0, -10))
masses = MassesCollection()
masses.add_mass(w1)
corrector = find_corrector(masses,
target_mass_kg=20,
target_x_m=50,
target_y_m=0,
target_z_m=0)
assert corrector.mass_kg == 10
assert corrector.cg_m.x == 90
assert corrector.cg_m.y == 0
assert corrector.cg_m.z == 10
# should work with the weight instead of the collection
corrector = find_corrector(w1,
target_mass_kg=20,
target_x_m=50,
target_y_m=0,
target_z_m=0)
assert corrector.mass_kg == 10
assert corrector.cg_m.x == 90
assert corrector.cg_m.y == 0
assert corrector.cg_m.z == 10
w1 = Mass.from_position_m(10, PositionM(10, 0, 0))
masses = MassesCollection()
masses.add_mass(w1)
corrector = find_corrector(masses,
target_mass_kg=20,
target_x_m=0,
target_y_m=0,
target_z_m=0)
assert corrector.mass_kg == 10
assert corrector.cg_m.x == -10
assert corrector.cg_m.y == 0
assert corrector.cg_m.z == 0
w1 = Mass.from_position_m(10, PositionM(0, 0, 0))
masses = MassesCollection()
masses.add_mass(w1)
corrector = find_corrector(masses,
target_mass_kg=20,
target_x_m=0,
target_y_m=0,
target_z_m=0)
assert corrector.mass_kg == 10
assert corrector.cg_m.x == 0
assert corrector.cg_m.y == 0
assert corrector.cg_m.z == 0
def test_total_force():
w1 = Mass.from_position_m(10, PositionM(2, 3, 4))
w2 = Mass.from_position_m(10, PositionM(2, 3, 4))
w3 = Mass.from_position_m(15, PositionM(2, 3, 4))
masses = MassesCollection()
masses.add_mass(w1)
masses.add_mass(w2)
masses.add_mass(w3)
expected_value = -343.23274999999995
tol = 1e-9
assert masses.force_N_m.fx == 0
assert masses.force_N_m.fy == 0
assert expected_value - tol <= masses.force_N_m.fz <= expected_value + tol
def test_find_corrector():
w1 = Mass.from_position_m(10, PositionM(10, 0, -10))
masses = MassesCollection()
masses.add_mass(w1)
corrector = find_corrector(masses,
target_mass_kg=20,
target_x_m=50,
target_y_m=0,
target_z_m=0)
expected_value = 98.06649999999999
tol = 1e-9
assert expected_value - tol <= corrector.weight_N <= expected_value + tol
def test_corrector_force():
w1 = Mass.from_position_m(10, PositionM(10, 0, -10))
masses = MassesCollection()
masses.add_mass(w1)
corrector = find_corrector(masses,
target_mass_kg=20,
target_x_m=50,
target_y_m=0,
target_z_m=0)
expected_value = -98.06649999999999
tol = 1e-9
assert corrector.force_N_m.fx == 0
assert corrector.force_N_m.fy == 0
assert expected_value - tol <= corrector.force_N_m.fz <= expected_value + tol
assert corrector.force_N_m.px == 90
assert corrector.force_N_m.py == 0
assert corrector.force_N_m.pz == 10
def test_negative_weight():
r"""Weight with a negative value (here -10)."""
with pytest.raises(ValueError):
_ = Mass.from_position_m(-10, PositionM(2, 3, 4), allow_negative_mass=False)
def load_masses_from_file(
filename: str) -> Tuple[MassesCollection, str, str, int]:
r"""Load the mass collection from a weights file.
Parameters
----------
filename : Path to the file
The file has the following format:
# comment
mass_unit, position_unit
mass_1, x_coordinate_1, y_coordinate_1, z_coordinate_1, name
mass_2, x_coordinate_2, y_coordinate_2, z_coordinate_2, name
...
mass_n, x_coordinate_n, y_coordinate_n, z_coordinate_n, name
Returns
-------
masses collection, initial_mass_unit, initial_position_unit
"""
masses = MassesCollection()
with open(filename) as f:
# Do not consider comment lines and empty lines
lines = list(
filter(lambda l: not l.startswith("#") and len(l) > 0,
f.readlines()))
# units
units_data = (lines[0].strip()).split(",")
initial_mass_unit = units_data[0].strip()
initial_position_unit = units_data[1].strip()
# Counter for templated lines
nb_templated_lines = 0
# data
for line in lines[1:]:
if "{{" not in line:
# The line is a plain line (i.e. not a templated line)
parts = (line.strip()).split(",")
w = float(parts[0])
x = float(parts[1])
y = float(parts[2])
z = float(parts[3])
try:
name = parts[4].strip()
except IndexError:
name = ""
kwargs_weight = {initial_mass_unit: w}
mass_kg = kg(**kwargs_weight)
position = Position(x, y, z, initial_position_unit)
position_m = position2positionm(position)
mass = Mass.from_position_m(mass_kg, position_m, name)
masses.add_mass(mass)
else:
# This is a templated line, do not use it to compute the weights collection
nb_templated_lines += 1
return masses, initial_mass_unit, initial_position_unit, nb_templated_lines