def weights(obj):
""" Returns Ship weights list. If weights has not been sets,
this tool creates it.
@param obj Ship object
@return Weights list. None if errors
"""
# Test if is a ship instance
props = obj.PropertiesList
try:
props.index("IsShip")
except ValueError:
return None
if not obj.IsShip:
return None
# Test if properties already exist
try:
props.index("WeightNames")
except ValueError:
obj.addProperty(
"App::PropertyStringList", "WeightNames", "Ship",
str(Translator.translate("Ship Weights names"))).WeightNames = [
Translator.translate("Lightweight").__str__()
]
try:
props.index("WeightMass")
except ValueError:
# Compute mass aproximation
from shipHydrostatics import Tools
disp = Tools.Displacement(obj, obj.Draft, 0.0)
obj.addProperty(
"App::PropertyFloatList", "WeightMass", "Ship",
str(Translator.translate("Ship Weights masses"))).WeightMass = [
1000.0 * disp[1]
]
try:
props.index("WeightPos")
except ValueError:
# Compute mass aproximation
from shipHydrostatics import Tools
disp = Tools.Displacement(obj, obj.Draft, 0.0)
obj.addProperty(
"App::PropertyVectorList", "WeightPos", "Ship",
str(Translator.translate(
"Ship Weights centers of gravity"))).WeightPos = [
Vector(disp[2], 0.0, obj.Draft)
]
# Setup list
weights = []
for i in range(0, len(obj.WeightNames)):
weights.append(
[obj.WeightNames[i], obj.WeightMass[i], obj.WeightPos[i]])
return weights
def onUpdate(self):
""" Method called when update data request.
"""
if not self.ship:
return
# Calculate drafts
angle = math.radians(self.form.trim.value())
L = self.ship.Length
draftAP = self.form.draft.value() + 0.5 * L * math.tan(angle)
if draftAP < 0.0:
draftAP = 0.0
draftFP = self.form.draft.value() - 0.5 * L * math.tan(angle)
if draftFP < 0.0:
draftFP = 0.0
# Calculate hydrostatics involved
data = Hydrostatics.Displacement(self.ship, self.form.draft.value(),
self.form.trim.value())
# Prepare the string in html format
string = 'L = %g [m]<BR>' % (self.ship.Length)
string = string + 'B = %g [m]<BR>' % (self.ship.Beam)
string = string + 'T = %g [m]<HR>' % (self.form.draft.value())
string = string + 'Trim = %g [degrees]<BR>' % (self.form.trim.value())
string = string + 'T<sub>AP</sub> = %g [m]<BR>' % (draftAP)
string = string + 'T<sub>FP</sub> = %g [m]<HR>' % (draftFP)
string = string + Translator.translate(
'Displacement') + ' = %g [ton]<BR>' % (data[1])
string = string + 'XCB = %g [m]' % (data[2])
# Set the document
self.form.output.setHtml(string)
def accept(self):
if not self.ship:
return False
self.save()
# Plot data
data = Hydrostatics.Displacement(self.ship, self.form.draft.value(),
self.form.trim.value())
x = self.ship.xSection[:]
y = data[0]
disp = data[1]
xcb = data[2]
Plot.Plot(x, y, disp, xcb, self.ship)
self.preview.clean()
return True
def computeDraft(self, disp, trim=0.0):
""" Computes ship draft.
@param disp Ship displacement.
@param trim Trim angle [degrees].
@return Ship draft, and longitudinal bouyance center position. None if errors detected.
"""
if not self.ship:
return None
# Initial condition
dens = 1025
bbox = self.ship.Shape.BoundBox
draft = bbox.ZMin
dx = bbox.XMax - bbox.XMin
dy = bbox.YMax - bbox.YMin
w = 0.0
xcb = 0.0
while(abs(disp - w)/disp > 0.01):
draft = draft + (disp - w) / (dens*dx*dy)
ww = Hydrostatics.Displacement(self.ship, draft, trim)
w = 1000.0*ww[1]
xcb = ww[2]
return [draft,xcb]
