Added Draft, displacement and XCB widget indicator

src/Mod/Ship/Instance.py

@@ -98,7 +98,6 @@ class Ship:
         @param nS Number of sections
         @param nP Number of points per section
         """
-        print(nS,nP)
         self.obj.addProperty("App::PropertyInteger","nSections","Ship", str(Translator.translate("Number of sections"))).nSections=nS
         self.obj.addProperty("App::PropertyIntegerList","nPoints","Ship", str(Translator.translate("List of number of points per sections (accumulated histogram)"))).nPoints=[0]
         self.obj.addProperty("App::PropertyFloatList","xSection","Ship", str(Translator.translate("List of sections x coordinate"))).xSection=[]
@@ -168,6 +167,8 @@ class Ship:
             for j in range(0,len(section)):
                 mSections.append(section[j])
         # Save data
+        for i in range(1,len(nPoints)):
+            nPoints[i] = nPoints[i] + nPoints[i-1]
         self.obj.nPoints   = nPoints[:]
         self.obj.xSection  = xSection[:]
         self.obj.mSections = mSections[:]
@@ -661,10 +662,8 @@ def sections(obj):
     histogram = obj.nPoints[:]
     points    = obj.mSections[:]
     sections  = []
-    print(histogram)
     for i in range(0, len(histogram) - 1):
         sections.append([])
-        print(histogram[i],histogram[i+1])
         for j in range(histogram[i],histogram[i+1]):
             sections[i].append(points[j])
     return sections

src/Mod/Ship/shipAreasCurve/TaskPanel.py

@@ -181,14 +181,14 @@ class TaskPanel:
         # Calculate drafts
         angle = math.radians(self.form.trim.value())
         L = self.ship.Length
-        draftAP = self.form.trim.value() + 0.5*L*math.tan(angle)
+        draftAP = self.form.draft.value() + 0.5*L*math.tan(angle)
         if draftAP < 0.0:
             draftAP = 0.0
-        draftFP = self.form.trim.value() - 0.5*L*math.tan(angle)
+        draftFP = self.form.draft.value() - 0.5*L*math.tan(angle)
         if draftFP < 0.0:
             draftFP = 0.0
         # Calculate hydrostatics involved
-        disp = Hydrostatics.Displacement(self.ship,self.form.draft.value(),self.form.trim.value())
+        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)
@@ -196,8 +196,8 @@ class TaskPanel:
         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>' % (disp[0])
-        string = string + 'XCB = %g [m]' % (disp[0])
+        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)
 

src/Mod/Ship/shipHydrostatics/Tools.py

@@ -25,12 +25,80 @@ import math
 # FreeCAD modules
 import FreeCAD as App
 import FreeCADGui as Gui
+# Module
+import Instance
 
 def Displacement(ship, draft, trim):
     """ Calculate ship displacement.
     @param ship Selected ship instance
     @param traft Draft.
     @param trim Trim in degrees.
-    @return Ship displacement, also X bouyance center coordinate is provided.
+    @return [areas,disp,xcb]: \n
+    areas : Area of each section \n
+    disp: Ship displacement \n
+    xcb: X bouyance center coordinate
     """
-    return [0.0, 0.0]
+    angle    = math.radians(trim)
+    sections = Instance.sections(ship)
+    xCoord   = ship.xSection[:]
+    areas    = []
+    vol      = 0.0
+    moment   = 0.0
+    if not sections:
+        return [[],0.0,0.0]
+    for i in range(0, len(sections)):
+        # Get the section
+        section = sections[i]
+        if len(section) < 2:    # Empty section
+            areas.append(0.0)
+            continue
+        # Get the position of the section
+        x = xCoord[i]
+        # Get the maximum Z value
+        Z = draft - x*math.tan(angle)
+        # Count the number of valid points
+        n = 0
+        for j in range(0,len(section)):
+            z = section[j].z
+            if z > Z:
+                break
+            n = n+1
+        # Discard invalid sections
+        if n == 0:
+            areas.append(0.0)
+            continue
+        # Truncate only valid points
+        points = section[0:n]
+        # Study if additional point is needed
+        if n < len(section):
+            y0 = section[n-1].y
+            z0 = section[n-1].z
+            y1 = section[n].y
+            z1 = section[n].z
+            factor = (Z - z0) / (z1 - z0)
+            y = y0 + factor*(y1 - y0)
+            points.append(App.Base.Vector(x,y,Z))
+        # Integrate area
+        area = 0.0
+        for j in range(0, len(points)-1):
+            y0 = abs(points[j].y)
+            z0 = points[j].z
+            y1 = abs(points[j+1].y)
+            z1 = points[j+1].z
+            y  = 0.5 * (y0 + y1)
+            dz = z1 - z0
+            area = area + 2.0*y*dz	# 2x because only half ship is represented
+        areas.append(area)
+        # Add volume & moment if proceed
+        if i > 0:
+            dx     = xCoord[i] - xCoord[i-1]
+            x      = 0.5*(xCoord[i] + xCoord[i-1])
+            area   = 0.5*(areas[i] + areas[i-1])
+            vol    = vol + area*dx
+            moment = moment + area*dx*x
+    # Compute displacement and xcb
+    disp = vol / 1.025  # rho = 1.025 ton/m3 (salt water density)
+    xcb  = 0.0
+    if vol > 0.0:
+        xcb  = moment / vol
+    return [areas,disp,xcb]