Part: implement BSplineSurface.buildFromNSections based on GeomFill_NSections

src/Mod/Part/App/BSplineSurfacePy.xml

@@ -721,6 +721,13 @@
 					arguments: poles (sequence of sequence of Base.Vector), umults, vmults, [uknots, vknots, uperiodic, vperiodic, udegree, vdegree, weights (sequence of sequence of float)]
 				</UserDocu>
 			</Documentation>
-	</Methode>
+		</Methode>
+		<Methode Name="buildFromNSections">
+			<Documentation>
+				<UserDocu>
+					Builds a B-Spline from a list of control curves
+				</UserDocu>
+			</Documentation>
+		</Methode>
 	</PythonExport>
 </GenerateModel>

src/Mod/Part/App/BSplineSurfacePyImp.cpp

@@ -35,6 +35,7 @@
 # include <GeomAPI_PointsToBSplineSurface.hxx>
 # include <GeomAbs_Shape.hxx>
 #endif
+# include <GeomFill_NSections.hxx>
 
 #include <Base/GeometryPyCXX.h>
 #include <Base/VectorPy.h>
@@ -1511,6 +1512,66 @@ PyObject* BSplineSurfacePy::buildFromPolesMultsKnots(PyObject *args, PyObject *k
     }
 }
 
+/*!
+ * \code
+c = Part.Circle()
+c.Radius=50
+c = c.trim(0, math.pi)
+
+e1 = Part.Ellipse()
+e1.Center = (0, 0, 75)
+e1.MajorRadius = 30
+e1.MinorRadius = 5
+e1 = e1.trim(0, math.pi)
+
+e2 = Part.Ellipse()
+e2.Center = (0, 0, 100)
+e2.MajorRadius = 20
+e2.MinorRadius = 5
+e2 = e2.trim(0, math.pi)
+
+bs = Part.BSplineSurface()
+bs.buildFromNSections([c, e1, e2])
+ * \endcode
+ */
+PyObject* BSplineSurfacePy::buildFromNSections(PyObject *args)
+{
+    PyObject* list;
+    PyObject* refSurf = Py_False;
+    if (!PyArg_ParseTuple(args, "O|O!", &list, &PyBool_Type, &refSurf))
+        return nullptr;
+
+    try {
+        TColGeom_SequenceOfCurve curveSeq;
+        Py::Sequence curves(list);
+        for (Py::Sequence::iterator it = curves.begin(); it != curves.end(); ++it) {
+            Py::Object obj(*it);
+            if (PyObject_TypeCheck(obj.ptr(), &GeometryCurvePy::Type)) {
+                GeomCurve* geom = static_cast<GeometryCurvePy*>(obj.ptr())->getGeomCurvePtr();
+                curveSeq.Append(Handle(Geom_Curve)::DownCast(geom->handle()));
+            }
+        }
+
+        GeomFill_NSections fillOp(curveSeq);
+        if (PyObject_IsTrue(refSurf)) {
+            Handle(Geom_BSplineSurface) ref = Handle(Geom_BSplineSurface)::DownCast
+                (getGeometryPtr()->handle());
+            fillOp.SetSurface(ref);
+        }
+
+        fillOp.ComputeSurface();
+
+        Handle(Geom_BSplineSurface) aSurf = fillOp.BSplineSurface();
+        this->getGeomBSplineSurfacePtr()->setHandle(aSurf);
+        Py_Return;
+    }
+    catch (const Standard_Failure& e) {
+        Standard_CString msg = e.GetMessageString();
+        PyErr_SetString(PartExceptionOCCError, msg  ? msg : "");
+        return nullptr;
+    }
+}
+
 Py::Long BSplineSurfacePy::getUDegree(void) const
 {
     Handle(Geom_BSplineSurface) surf = Handle(Geom_BSplineSurface)::DownCast