diff --git a/src/Mod/Surface/App/AppSurface.cpp b/src/Mod/Surface/App/AppSurface.cpp
index e7a87e8f12..22ceb69343 100644
--- a/src/Mod/Surface/App/AppSurface.cpp
+++ b/src/Mod/Surface/App/AppSurface.cpp
@@ -65,7 +65,7 @@ PyMOD_INIT_FUNC(Surface)
     }
     catch(const Base::Exception& e) {
         PyErr_SetString(PyExc_ImportError, e.what());
-        PyMOD_Return(0);
+        PyMOD_Return(nullptr);
     }
 
     PyObject* mod = Surface::initModule();
diff --git a/src/Mod/Surface/App/FeatureCut.cpp b/src/Mod/Surface/App/FeatureCut.cpp
index e950d672aa..7e617e4224 100644
--- a/src/Mod/Surface/App/FeatureCut.cpp
+++ b/src/Mod/Surface/App/FeatureCut.cpp
@@ -43,7 +43,7 @@ PROPERTY_SOURCE(Surface::Cut, Part::Feature)
 
 Cut::Cut()
 {
-    ADD_PROPERTY(ShapeList,(0,"TopoDS_Shape"));
+    ADD_PROPERTY(ShapeList,(nullptr,"TopoDS_Shape"));
     ShapeList.setScope(App::LinkScope::Global);
 }
 
@@ -95,7 +95,7 @@ App::DocumentObjectExecReturn *Cut::execute(void)
         }
 
         this->Shape.setValue(aCutShape);
-        return 0;
+        return nullptr;
     }
     catch (Standard_Failure& e) {
 
diff --git a/src/Mod/Surface/App/FeatureExtend.cpp b/src/Mod/Surface/App/FeatureExtend.cpp
index 389ea9986d..67cf6c9a92 100644
--- a/src/Mod/Surface/App/FeatureExtend.cpp
+++ b/src/Mod/Surface/App/FeatureExtend.cpp
@@ -48,7 +48,7 @@ PROPERTY_SOURCE(Surface::Extend, Part::Spline)
 
 Extend::Extend() : lockOnChangeMutex(false)
 {
-    ADD_PROPERTY(Face,(0));
+    ADD_PROPERTY(Face,(nullptr));
     Face.setScope(App::LinkScope::Global);
     ADD_PROPERTY(Tolerance, (0.1));
     Tolerance.setConstraints(&ToleranceRange);
diff --git a/src/Mod/Surface/App/FeatureFilling.cpp b/src/Mod/Surface/App/FeatureFilling.cpp
index d0b17c2362..946bcaea43 100644
--- a/src/Mod/Surface/App/FeatureFilling.cpp
+++ b/src/Mod/Surface/App/FeatureFilling.cpp
@@ -47,19 +47,19 @@ PROPERTY_SOURCE(Surface::Filling, Part::Spline)
 
 Filling::Filling()
 {
-    ADD_PROPERTY_TYPE(BoundaryEdges,(0,""), "Filling", App::Prop_None, "Boundary Edges (C0 is required for edges without a corresponding face)");
+    ADD_PROPERTY_TYPE(BoundaryEdges,(nullptr,""), "Filling", App::Prop_None, "Boundary Edges (C0 is required for edges without a corresponding face)");
     ADD_PROPERTY_TYPE(BoundaryFaces,(""), "Filling", App::Prop_None, "Boundary Faces");
     ADD_PROPERTY_TYPE(BoundaryOrder,(-1), "Filling", App::Prop_None, "Order of constraint on boundary faces (C0, G1 and G2 are possible)");
 
-    ADD_PROPERTY_TYPE(UnboundEdges,(0,""), "Filling", App::Prop_None, "Unbound constraint edges (C0 is required for edges without a corresponding face)");
+    ADD_PROPERTY_TYPE(UnboundEdges,(nullptr,""), "Filling", App::Prop_None, "Unbound constraint edges (C0 is required for edges without a corresponding face)");
     ADD_PROPERTY_TYPE(UnboundFaces,(""), "Filling", App::Prop_None, "Unbound constraint faces");
     ADD_PROPERTY_TYPE(UnboundOrder,(-1), "Filling", App::Prop_None, "Order of constraint on curve faces (C0, G1 and G2 are possible)");
 
-    ADD_PROPERTY_TYPE(FreeFaces,(0,""), "Filling", App::Prop_None, "Free constraint on a face");
+    ADD_PROPERTY_TYPE(FreeFaces,(nullptr,""), "Filling", App::Prop_None, "Free constraint on a face");
     ADD_PROPERTY_TYPE(FreeOrder,(0), "Filling", App::Prop_None, "Order of constraint on free faces");
 
-    ADD_PROPERTY_TYPE(Points,(0,""), "Filling", App::Prop_None, "Constraint Points (on Surface)");
-    ADD_PROPERTY_TYPE(InitialFace,(0), "Filling", App::Prop_None, "Initial surface to use");
+    ADD_PROPERTY_TYPE(Points,(nullptr,""), "Filling", App::Prop_None, "Constraint Points (on Surface)");
+    ADD_PROPERTY_TYPE(InitialFace,(nullptr), "Filling", App::Prop_None, "Initial surface to use");
 
     ADD_PROPERTY_TYPE(Degree,(3), "Filling", App::Prop_None, "Starting degree");
     ADD_PROPERTY_TYPE(PointsOnCurve,(15), "Filling", App::Prop_None, "Number of points on an edge for constraint");
diff --git a/src/Mod/Surface/App/FeatureGeomFillSurface.cpp b/src/Mod/Surface/App/FeatureGeomFillSurface.cpp
index 8bad1eba8c..4ccddc1635 100644
--- a/src/Mod/Surface/App/FeatureGeomFillSurface.cpp
+++ b/src/Mod/Surface/App/FeatureGeomFillSurface.cpp
@@ -94,7 +94,7 @@ void ShapeValidator::checkEdge(const TopoDS_Shape& shape)
 void ShapeValidator::checkAndAdd(const TopoDS_Shape &shape, Handle(ShapeExtend_WireData) *aWD)
 {
     checkEdge(shape);
-    if (aWD != NULL) {
+    if (aWD != nullptr) {
         BRepBuilderAPI_Copy copier(shape);
         // make a copy of the shape and the underlying geometry to avoid to affect the input shapes
         (*aWD)->Add(TopoDS::Edge(copier.Shape()));
@@ -104,7 +104,7 @@ void ShapeValidator::checkAndAdd(const TopoDS_Shape &shape, Handle(ShapeExtend_W
 void ShapeValidator::checkAndAdd(const Part::TopoShape &ts, const char *subName, Handle(ShapeExtend_WireData) *aWD)
 {
     try {
-        if (subName != NULL && *subName != '\0') {
+        if (subName != nullptr && *subName != '\0') {
             //we want only the subshape which is linked
             checkAndAdd(ts.getSubShape(subName), aWD);
         }
@@ -126,12 +126,12 @@ void ShapeValidator::checkAndAdd(const Part::TopoShape &ts, const char *subName,
 
 PROPERTY_SOURCE(Surface::GeomFillSurface, Part::Spline)
 
-const char* GeomFillSurface::FillTypeEnums[]    = {"Stretched", "Coons", "Curved", NULL};
+const char* GeomFillSurface::FillTypeEnums[]    = {"Stretched", "Coons", "Curved", nullptr};
 
 GeomFillSurface::GeomFillSurface(): Spline()
 {
     ADD_PROPERTY(FillType, ((long)0));
-    ADD_PROPERTY(BoundaryList, (0, "Dummy"));
+    ADD_PROPERTY(BoundaryList, (nullptr, "Dummy"));
     ADD_PROPERTY(ReversedList, (false));
     FillType.setEnums(FillTypeEnums);
     BoundaryList.setScope(App::LinkScope::Global);
diff --git a/src/Mod/Surface/App/FeatureGeomFillSurface.h b/src/Mod/Surface/App/FeatureGeomFillSurface.h
index 905b8e79c5..501d98e9d9 100644
--- a/src/Mod/Surface/App/FeatureGeomFillSurface.h
+++ b/src/Mod/Surface/App/FeatureGeomFillSurface.h
@@ -46,8 +46,8 @@ public:
     ShapeValidator();
     void initValidator(void);
     void checkEdge(const TopoDS_Shape& shape);
-    void checkAndAdd(const TopoDS_Shape &shape, Handle(ShapeExtend_WireData) *aWD = NULL);
-    void checkAndAdd(const Part::TopoShape &ts, const char *subName, Handle(ShapeExtend_WireData) *aWire = NULL);
+    void checkAndAdd(const TopoDS_Shape &shape, Handle(ShapeExtend_WireData) *aWD = nullptr);
+    void checkAndAdd(const Part::TopoShape &ts, const char *subName, Handle(ShapeExtend_WireData) *aWire = nullptr);
 
     bool isBezier() const {
         return willBezier;
diff --git a/src/Mod/Surface/App/FeatureSewing.cpp b/src/Mod/Surface/App/FeatureSewing.cpp
index c4f278cfba..c9971dd147 100644
--- a/src/Mod/Surface/App/FeatureSewing.cpp
+++ b/src/Mod/Surface/App/FeatureSewing.cpp
@@ -43,7 +43,7 @@ PROPERTY_SOURCE(Surface::Sewing, Part::Feature)
 
 Sewing::Sewing()
 {
-    ADD_PROPERTY_TYPE(ShapeList,(0,""), "Sewing", App::Prop_None, "Input shapes");
+    ADD_PROPERTY_TYPE(ShapeList,(nullptr,""), "Sewing", App::Prop_None, "Input shapes");
     ADD_PROPERTY_TYPE(Tolerance,(Precision::Confusion()), "Sewing", App::Prop_None, "Sewing tolerance");
     ADD_PROPERTY_TYPE(SewingOption,(true), "Sewing", App::Prop_None, "Sewing option");
     ADD_PROPERTY_TYPE(DegenerateShape,(true), "Sewing", App::Prop_None, "Analysis of degenerated shapes");
diff --git a/src/Mod/Surface/Gui/AppSurfaceGui.cpp b/src/Mod/Surface/Gui/AppSurfaceGui.cpp
index 419c8b53f8..90849781c0 100644
--- a/src/Mod/Surface/Gui/AppSurfaceGui.cpp
+++ b/src/Mod/Surface/Gui/AppSurfaceGui.cpp
@@ -65,7 +65,7 @@ PyMOD_INIT_FUNC(SurfaceGui)
 {
     if (!Gui::Application::Instance) {
         PyErr_SetString(PyExc_ImportError, "Cannot load Gui module in console application.");
-        PyMOD_Return(0);
+        PyMOD_Return(nullptr);
     }
 
     Base::Interpreter().runString("import Surface");
diff --git a/src/Mod/Surface/Gui/TaskFilling.cpp b/src/Mod/Surface/Gui/TaskFilling.cpp
index ee21ce2bd3..d45e3adba5 100644
--- a/src/Mod/Surface/Gui/TaskFilling.cpp
+++ b/src/Mod/Surface/Gui/TaskFilling.cpp
@@ -533,7 +533,7 @@ void FillingPanel::on_listBoundary_itemDoubleClicked(QListWidgetItem* item)
                 const TopTools_ListOfShape& adj_faces = edge2Face.FindFromKey(edge);
                 if (adj_faces.Extent() > 0) {
                     int n = adj_faces.Extent();
-                    ui->statusLabel->setText(tr("Edge has %n adjacent faces", 0, n));
+                    ui->statusLabel->setText(tr("Edge has %n adjacent faces", nullptr, n));
 
                     // fill up the combo boxes
                     modifyBoundary(true);
@@ -859,14 +859,14 @@ TaskFilling::TaskFilling(ViewProviderFilling* vp, Surface::Filling* obj)
     widget1 = new FillingPanel(vp, obj);
     Gui::TaskView::TaskBox* taskbox1 = new Gui::TaskView::TaskBox(
         Gui::BitmapFactory().pixmap("Surface_Filling"),
-        widget1->windowTitle(), true, 0);
+        widget1->windowTitle(), true, nullptr);
     taskbox1->groupLayout()->addWidget(widget1);
     Content.push_back(taskbox1);
 
     // second task box
     widget2 = new FillingEdgePanel(vp, obj);
     Gui::TaskView::TaskBox* taskbox2 = new Gui::TaskView::TaskBox(
-        QPixmap(), widget2->windowTitle(), true, 0);
+        QPixmap(), widget2->windowTitle(), true, nullptr);
     taskbox2->groupLayout()->addWidget(widget2);
     Content.push_back(taskbox2);
     taskbox2->hideGroupBox();
@@ -874,7 +874,7 @@ TaskFilling::TaskFilling(ViewProviderFilling* vp, Surface::Filling* obj)
     // third task box
     widget3 = new FillingVertexPanel(vp, obj);
     Gui::TaskView::TaskBox* taskbox3 = new Gui::TaskView::TaskBox(
-        QPixmap(), widget3->windowTitle(), true, 0);
+        QPixmap(), widget3->windowTitle(), true, nullptr);
     taskbox3->groupLayout()->addWidget(widget3);
     Content.push_back(taskbox3);
     taskbox3->hideGroupBox();
diff --git a/src/Mod/Surface/Gui/TaskFillingEdge.cpp b/src/Mod/Surface/Gui/TaskFillingEdge.cpp
index 1955892770..f5c34415f6 100644
--- a/src/Mod/Surface/Gui/TaskFillingEdge.cpp
+++ b/src/Mod/Surface/Gui/TaskFillingEdge.cpp
@@ -330,7 +330,7 @@ void FillingEdgePanel::on_listUnbound_itemDoubleClicked(QListWidgetItem* item)
                 const TopTools_ListOfShape& adj_faces = edge2Face.FindFromKey(edge);
                 if (adj_faces.Extent() > 0) {
                     int n = adj_faces.Extent();
-                    ui->statusLabel->setText(tr("Edge has %n adjacent face(s)", 0, n));
+                    ui->statusLabel->setText(tr("Edge has %n adjacent face(s)", nullptr, n));
 
                     // fill up the combo boxes
                     modifyBoundary(true);
diff --git a/src/Mod/Surface/Gui/TaskGeomFillSurface.cpp b/src/Mod/Surface/Gui/TaskGeomFillSurface.cpp
index d36d2d3c8c..ef3b359511 100644
--- a/src/Mod/Surface/Gui/TaskGeomFillSurface.cpp
+++ b/src/Mod/Surface/Gui/TaskGeomFillSurface.cpp
@@ -587,7 +587,7 @@ TaskGeomFillSurface::TaskGeomFillSurface(ViewProviderGeomFillSurface* vp, Surfac
     widget->setWindowTitle(QObject::tr("Surface"));
     taskbox = new Gui::TaskView::TaskBox(
         Gui::BitmapFactory().pixmap("Surface_BSplineSurface"),
-        widget->windowTitle(), true, 0);
+        widget->windowTitle(), true, nullptr);
     taskbox->groupLayout()->addWidget(widget);
     Content.push_back(taskbox);
 }
diff --git a/src/Mod/Surface/Gui/TaskSections.cpp b/src/Mod/Surface/Gui/TaskSections.cpp
index 6eef1858fd..d1ee741d54 100644
--- a/src/Mod/Surface/Gui/TaskSections.cpp
+++ b/src/Mod/Surface/Gui/TaskSections.cpp
@@ -555,7 +555,7 @@ TaskSections::TaskSections(ViewProviderSections* vp, Surface::Sections* obj)
     widget1 = new SectionsPanel(vp, obj);
     Gui::TaskView::TaskBox* taskbox1 = new Gui::TaskView::TaskBox(
         Gui::BitmapFactory().pixmap("Surface_Sections"),
-        widget1->windowTitle(), true, 0);
+        widget1->windowTitle(), true, nullptr);
     taskbox1->groupLayout()->addWidget(widget1);
     Content.push_back(taskbox1);
 }