Gear.py

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#Involute Gears Generation Script
#by Marcin Wanczyk (dj_who)
#(c) 2011 LGPL


import FreeCAD, FreeCADGui, Part, Draft, math, MeshPart, Mesh
from PyQt4 import QtGui,QtCore
App=FreeCAD
Gui=FreeCADGui

def proceed():    
    QtGui.qApp.setOverrideCursor(QtCore.Qt.WaitCursor)
   
    if FreeCAD.ActiveDocument==None:
        FreeCAD.newDocument("Gear")

    oldDocumentObjects=App.ActiveDocument.Objects

    try:
        N = int(l1.text())   
        p = float(l2.text())
        alfa = int(l3.text())
        y = float(l4.text())       #standard value y<1 for gear drives y>1 for Gear pumps
        m=p/math.pi                #standard value 0.06, 0.12, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 60 (polish norm)
        c = float(l5.text())*m     #standard value 0,1*m - 0,3*m
        j = float(l6.text())*m     #standard value 0,015 - 0,04*m
        width = float(l7.text())   #gear width           
    except:
        FreeCAD.Console.PrintError("Wrong input! Only numbers allowed...\n")
    
    
    #tooth hight
    h=2*y*m+c    

    #pitch diameter
    d=N*m

    #root diameter    
    df=d - 2*y*m - 2*c              #df=d-2hf where and hf=y*m+c 

    #addendum diameter    
    da=d + 2*y*m                    #da=d+2ha where ha=y*m    

    #base diameter for involute
    db=d * math.cos(math.radians(alfa))


    #Base circle
    baseCircle=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","BaseCircle")
    Draft.Circle(baseCircle)
    Draft.ViewProviderCircle(baseCircle.ViewObject)
    baseCircle.Radius = db/2
    baseCircle.FirstAngle=0.0
    baseCircle.LastAngle=0.0
    
    #Root circle
    rootCircle=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","RootCircle")
    Draft.Circle(rootCircle)
    Draft.ViewProviderCircle(rootCircle.ViewObject)
    rootCircle.Radius = df/2
    rootCircle.FirstAngle=0.0
    rootCircle.LastAngle=0.0

    #Addendum circle
    addendumCircle=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","AddendumCircle")
    Draft.Circle(addendumCircle)
    Draft.ViewProviderCircle(addendumCircle.ViewObject)
    addendumCircle.Radius = da/2
    addendumCircle.FirstAngle=0.0
    addendumCircle.LastAngle=0.0

    #Pitch circle
    pitchCircle=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","PitchCircle")
    Draft.Circle(pitchCircle)
    Draft.ViewProviderCircle(pitchCircle.ViewObject)
    pitchCircle.Radius = d/2
    pitchCircle.FirstAngle=0.0
    pitchCircle.LastAngle=0.0

#************ Calculating right sides of teeth
    #Involute of base circle
    involute=[]
    involutee=[]
    involutesav=[]

    for t in range(0,60,1):
        x=db/2*(math.cos(math.radians(t))+math.radians(t)*math.sin(math.radians(t)))
        y=db/2*(math.sin(math.radians(t))-math.radians(t)*math.cos(math.radians(t)))    
        involute.append(Part.Vertex(x,y,0).Point)

#************ Drawing rigth sides of teeth   
    involutesav.extend(involute)
    involutee.extend(involute)

    for angle in range(1,N+1,1):
        involuteobj = FreeCAD.ActiveDocument.addObject("Part::Feature","InvoluteL"+str(angle))
        involutee.insert(0,(0,0,0))        
        involuteshape = Part.makePolygon(involutee)        
        involuteobj.Shape=involuteshape
        involutee=[]
        for num in range(0,60,1):
            point=involute.pop()
            pointt=Part.Vertex(point.x*math.cos(math.radians(angle*360/N)) - point.y*math.sin(math.radians(angle*360/N)),point.x*math.sin(math.radians(angle*360/N)) + point.y*math.cos(math.radians(angle*360/N)),0).Point
            involutee.insert(0,pointt)
        involute.extend(involutesav)
    involutee=[]
    
#************ Calculating difference between tooth spacing on BaseCircle and PitchCircle

    pc=App.ActiveDocument.getObject("PitchCircle")
    inv=App.ActiveDocument.getObject("InvoluteL1")
    cut=inv.Shape.cut(pc.Shape)
#    FreeCAD.ActiveDocument.addObject("Part::Feature","CutInv").Shape=cut
    invPoint=cut.Vertexes[0].Point


    diff=invPoint.y*2        # instead of making axial symmetry and calculating point distance.
    anglediff=2*math.asin(diff/d)

#************ Calculating left sides of teeth

#************ Inversing Involute
    for num in range(0,60,1):
        point=involute.pop()
        pointt=Part.Vertex(point.x,point.y*-1,0).Point
        involutee.insert(0,pointt)
    involute.extend(involutee)
    involutee=[]

#Normal tooth size calculated as: 0,5*  p    -      j                         j=m * 0,1 below are calculations
#                                 0,5*  p    -      m      * 0,1
#                                 0,5*  p    -     p   /pi * 0,1
#                                 0,5*360/N  - ((360/N)/pi)* 0,1
#                                 0,5*360/N  - (360/N)*((1/pi)*0,1)           j=(p/pi)*0,1
#                                 0,5*360/N  - (360/N)*((p/pi)*0,1)/p
#                                 0,5*360/N  - (360/N)*(    j     )/p
    for num in range(0,60,1):
        point=involute.pop()
        pointt=Part.Vertex(point.x*math.cos(math.radians(180/N-(360/N)*(j/p))+anglediff) - point.y*math.sin(math.radians(180/N-(360/N)*(j/p))+anglediff),point.x*math.sin(math.radians(180/N-(360/N)*(j/p))+anglediff) + point.y*math.cos(math.radians(180/N-(360/N)*(j/p))+anglediff),0).Point
        involutee.insert(0,pointt)
    involute.extend(involutee)
    involutesav=[]
    involutesav.extend(involute)

#************ Drawing left sides of teeth
    for angle in range(1,N+1,1):
        involuteobj = FreeCAD.ActiveDocument.addObject("Part::Feature","InvoluteR"+str(angle))
        involutee.insert(0,(0,0,0))
        involuteshape = Part.makePolygon(involutee)
        involuteobj.Shape=involuteshape
        involutee=[]
        for num in range(0,60,1):
            point=involute.pop()
            pointt=Part.Vertex(point.x*math.cos(math.radians(angle*360/N)) - point.y*math.sin(math.radians(angle*360/N)),point.x*math.sin(math.radians(angle*360/N)) + point.y*math.cos(math.radians(angle*360/N)),0).Point
            involutee.insert(0,pointt)
        involute.extend(involutesav)

    Gui.SendMsgToActiveView("ViewFit")

#************ Forming teeth

    cutCircle=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","CutCircle")
    Draft.Circle(cutCircle)
    Draft.ViewProviderCircle(cutCircle.ViewObject)
    cutCircle.Radius = da    # da because must be bigger than addendumCircle and bigger than whole construction da is right for this but it not has to be.       
    cutCircle.FirstAngle=0.0
    cutCircle.LastAngle=0.0

    
    cutTool=cutCircle.Shape.cut(addendumCircle.Shape)
    #cutshape=Part.show(cutTool)
    
    gearShape=rootCircle.Shape

    for invNum in range(1,N+1,1):      
        invL=App.ActiveDocument.getObject("InvoluteL"+str(invNum))
        invR=App.ActiveDocument.getObject("InvoluteR"+str(invNum))
        cutL=invL.Shape.cut(cutTool)
        cutR=invR.Shape.cut(cutTool)
        pointL=cutL.Vertexes.pop().Point
        pointR=cutR.Vertexes.pop().Point
        faceEdge=Part.makeLine(pointL,pointR)
        
        toothWhole=cutL.fuse(cutR)
        toothWhole=toothWhole.fuse(faceEdge)
        toothWire=Part.Wire(toothWhole.Edges)
        toothShape=Part.Face(toothWire)
#        tooth=App.ActiveDocument.addObject("Part::Feature","Tooth"+str(invNum))
#        tooth.Shape=toothShape
        gearShape=gearShape.fuse(toothShape)


    for o in App.ActiveDocument.Objects:
        if oldDocumentObjects.count(o)==0:
            App.ActiveDocument.removeObject(o.Name)

    gearFlat=App.ActiveDocument.addObject("Part::Feature","GearFlat")
    gearFlat.Shape=gearShape
    Gui.ActiveDocument.getObject(gearFlat.Name).Visibility=False

    gear=App.ActiveDocument.addObject("Part::Extrusion","Gear3D")
    gear.Base=gearFlat
    gear.Dir=(0,0,width)
    App.ActiveDocument.recompute()

    
    if c1.isChecked()==True:
        gearMesh=App.ActiveDocument.addObject("Mesh::Feature","Gear3D-mesh")

        faces = []
        triangles = gear.Shape.tessellate(1) # the number represents the precision of the tessellation)
        for tri in triangles[1]:
            face = []
            for i in range(3):
                vindex = tri[i]
                face.append(triangles[0][vindex])
            faces.append(face)
        mesh = Mesh.Mesh(faces)

        gearMesh.Mesh=mesh
        App.ActiveDocument.removeObject(gear.Name)
        App.ActiveDocument.removeObject(gearFlat.Name)


    App.ActiveDocument.recompute()
    Gui.SendMsgToActiveView("ViewFit")
    
    QtGui.qApp.restoreOverrideCursor()
 

    hide()

def hide():
    dialog.hide()

dialog = QtGui.QDialog()
dialog.resize(200,450)
dialog.setWindowTitle("Gear")
la = QtGui.QVBoxLayout(dialog)
t1 = QtGui.QLabel("Number of teeth (N)")
la.addWidget(t1)
l1 = QtGui.QLineEdit()
l1.setText("16")
la.addWidget(l1)
t2 = QtGui.QLabel("Circular pitch (p)")
la.addWidget(t2)
l2 = QtGui.QLineEdit()
l2.setText("1.65")
la.addWidget(l2)
t3 = QtGui.QLabel("Pressure angle (alfa)")
la.addWidget(t3)
l3 = QtGui.QLineEdit()
l3.setText("20")
la.addWidget(l3)
t4 = QtGui.QLabel("Tooth hight factor (y)")   
la.addWidget(t4)
l4 = QtGui.QLineEdit()
l4.setText("1.0")
la.addWidget(l4)
t5 = QtGui.QLabel("Tooth clearance (c)")   
la.addWidget(t5)
l5 = QtGui.QLineEdit()
l5.setText("0.1")
la.addWidget(l5)
t6 = QtGui.QLabel("Tooth lateral clearance (j)")   
la.addWidget(t6)
l6 = QtGui.QLineEdit()
l6.setText("0.04")
la.addWidget(l6)
t7 = QtGui.QLabel("Gear width")   
la.addWidget(t7)
l7 = QtGui.QLineEdit()
l7.setText("6.0")
la.addWidget(l7)
c1 = QtGui.QCheckBox("Create as a Mesh")
la.addWidget(c1)
e1 = QtGui.QLabel("(for faster rendering)")
commentFont=QtGui.QFont("Times",8,True)
e1.setFont(commentFont)
la.addWidget(e1)

okbox = QtGui.QDialogButtonBox(dialog)
okbox.setOrientation(QtCore.Qt.Horizontal)
okbox.setStandardButtons(QtGui.QDialogButtonBox.Cancel|QtGui.QDialogButtonBox.Ok)
la.addWidget(okbox)
QtCore.QObject.connect(okbox, QtCore.SIGNAL("accepted()"), proceed)
QtCore.QObject.connect(okbox, QtCore.SIGNAL("rejected()"), hide)
QtCore.QMetaObject.connectSlotsByName(dialog)
dialog.show()