+ fixes #0001247

src/Mod/Part/App/PrimitiveFeature.cpp

@@ -647,6 +647,7 @@ App::DocumentObjectExecReturn *Torus::execute(void)
 PROPERTY_SOURCE(Part::Helix, Part::Primitive)
 
 const char* Part::Helix::LocalCSEnums[]= {"Right-handed","Left-handed",NULL};
+const char* Part::Helix::StyleEnums  []= {"Old style","New style",NULL};
 
 Helix::Helix(void)
 {
@@ -660,13 +661,15 @@ Helix::Helix(void)
     Angle.setConstraints(&apexRange);
     ADD_PROPERTY_TYPE(LocalCoord,(long(0)),"Coordinate System",App::Prop_None,"Orientation of the local coordinate system of the helix");
     LocalCoord.setEnums(LocalCSEnums);
+    ADD_PROPERTY_TYPE(Style,(long(0)),"Helix style",App::Prop_Hidden,"Old style creates incorrect and new style create correct helices");
+    Style.setEnums(StyleEnums);
 }
 
 void Helix::onChanged(const App::Property* prop)
 {
     if (!isRestoring()) {
         if (prop == &Pitch || prop == &Height || prop == &Radius ||
-            prop == &Angle || prop == &LocalCoord) {
+            prop == &Angle || prop == &LocalCoord || prop == &Style) {
             try {
                 App::DocumentObjectExecReturn *ret = recompute();
                 delete ret;
@@ -690,6 +693,8 @@ short Helix::mustExecute() const
         return 1;
     if (LocalCoord.isTouched())
         return 1;
+    if (Style.isTouched())
+        return 1;
     return Primitive::mustExecute();
 }
 
@@ -701,8 +706,9 @@ App::DocumentObjectExecReturn *Helix::execute(void)
         Standard_Real myRadius = Radius.getValue();
         Standard_Real myAngle  = Angle.getValue();
         Standard_Boolean myLocalCS = LocalCoord.getValue() ? Standard_True : Standard_False;
+        Standard_Boolean myStyle = Style.getValue() ? Standard_True : Standard_False;
         TopoShape helix;
-        this->Shape.setValue(helix.makeHelix(myPitch, myHeight, myRadius, myAngle, myLocalCS));
+        this->Shape.setValue(helix.makeHelix(myPitch, myHeight, myRadius, myAngle, myLocalCS, myStyle));
     }
     catch (Standard_Failure) {
         Handle_Standard_Failure e = Standard_Failure::Caught();

src/Mod/Part/App/PrimitiveFeature.h

@@ -281,6 +281,7 @@ public:
     App::PropertyFloatConstraint Radius;
     App::PropertyFloatConstraint Angle;
     App::PropertyEnumeration     LocalCoord;
+    App::PropertyEnumeration     Style;
 
     /** @name methods override feature */
     //@{
@@ -298,6 +299,7 @@ protected:
 
 private:
     static const char* LocalCSEnums[];
+    static const char* StyleEnums[];
 };
 
 class PartExport Spiral : public Primitive

src/Mod/Part/App/TopoShape.cpp

@@ -1543,7 +1543,8 @@ TopoDS_Shape TopoShape::makeSweep(const TopoDS_Shape& profile, double tol, int f
 
 TopoDS_Shape TopoShape::makeHelix(Standard_Real pitch, Standard_Real height,
                                   Standard_Real radius, Standard_Real angle,
-                                  Standard_Boolean leftHanded) const
+                                  Standard_Boolean leftHanded,
+                                  Standard_Boolean newStyle) const
 {
     if (pitch < Precision::Confusion())
         Standard_Failure::Raise("Pitch of helix too small");
@@ -1578,15 +1579,18 @@ TopoDS_Shape TopoShape::makeHelix(Standard_Real pitch, Standard_Real height,
     Handle(Geom2d_Line) line = new Geom2d_Line(aAx2d);
     gp_Pnt2d beg = line->Value(0);
     gp_Pnt2d end = line->Value(sqrt(4.0*M_PI*M_PI+pitch*pitch)*(height/pitch));
-#if 0 // See discussion at 0001247: Part Conical Helix Height/Pitch Incorrect
-    if (angle >= Precision::Confusion()) {
-        // calculate end point for conical helix
-        Standard_Real v = height / cos(angle);
-        Standard_Real u = (height/pitch) * 2.0 * M_PI;
-        gp_Pnt2d cend(u, v);
-        end = cend;
+
+    if (newStyle) {
+        // See discussion at 0001247: Part Conical Helix Height/Pitch Incorrect
+        if (angle >= Precision::Confusion()) {
+            // calculate end point for conical helix
+            Standard_Real v = height / cos(angle);
+            Standard_Real u = (height/pitch) * 2.0 * M_PI;
+            gp_Pnt2d cend(u, v);
+            end = cend;
+        }
     }
-#endif
+
     Handle(Geom2d_TrimmedCurve) segm = GCE2d_MakeSegment(beg , end);
 
     TopoDS_Edge edgeOnSurf = BRepBuilderAPI_MakeEdge(segm , surf);

src/Mod/Part/App/TopoShape.h

@@ -161,7 +161,8 @@ public:
     TopoDS_Shape makeSweep(const TopoDS_Shape& profile, double, int) const;
     TopoDS_Shape makeTube(double radius, double tol, int cont, int maxdeg, int maxsegm) const;
     TopoDS_Shape makeHelix(Standard_Real pitch, Standard_Real height,
-        Standard_Real radius, Standard_Real angle=0, Standard_Boolean left=Standard_False) const;
+        Standard_Real radius, Standard_Real angle=0,
+        Standard_Boolean left=Standard_False, Standard_Boolean style=Standard_False) const;
     TopoDS_Shape makeThread(Standard_Real pitch, Standard_Real depth,
         Standard_Real height, Standard_Real radius) const;
     TopoDS_Shape makeLoft(const TopTools_ListOfShape& profiles, Standard_Boolean isSolid,

src/Mod/Part/Gui/DlgPrimitives.cpp

@@ -505,6 +505,7 @@ void DlgPrimitives::createPrimitive(const QString& placement)
                 "App.ActiveDocument.%1.Radius=%4\n"
                 "App.ActiveDocument.%1.Angle=%5\n"
                 "App.ActiveDocument.%1.LocalCoord=%6\n"
+                "App.ActiveDocument.%1.Style=1\n"
                 "App.ActiveDocument.%1.Placement=%7\n")
                 .arg(name)
                 .arg(ui.helixPitch->value(),0,'f',2)