diff --git a/src/Gui/View3DInventor.cpp b/src/Gui/View3DInventor.cpp
index 2b378dfb2f..c03281cfab 100644
--- a/src/Gui/View3DInventor.cpp
+++ b/src/Gui/View3DInventor.cpp
@@ -224,7 +224,7 @@ View3DInventor::~View3DInventor()
     }
 
     if (_viewerPy) {
-        static_cast<View3DInventorPy*>(_viewerPy)->_view = 0;
+        Base::PyGILStateLocker lock;
         Py_DECREF(_viewerPy);
     }
 
diff --git a/src/Gui/View3DPy.cpp b/src/Gui/View3DPy.cpp
index 469a365588..23a0a68da6 100644
--- a/src/Gui/View3DPy.cpp
+++ b/src/Gui/View3DPy.cpp
@@ -52,7 +52,6 @@
 #include "View3DViewerPy.h"
 #include "ActiveObjectList.h"
 #include "PythonWrapper.h"
-#include "MDIViewPy.h"
 
 
 #include <Base/Console.h>
@@ -82,7 +81,6 @@ void View3DInventorPy::init_type()
     behaviors().supportGetattr();
     behaviors().supportSetattr();
 
-    add_varargs_method("message",&View3DInventorPy::message,"message()");
     add_varargs_method("fitAll",&View3DInventorPy::fitAll,"fitAll()");
     add_keyword_method("boxZoom",&View3DInventorPy::boxZoom,"boxZoom()");
 
@@ -213,7 +211,7 @@ void View3DInventorPy::init_type()
 }
 
 View3DInventorPy::View3DInventorPy(View3DInventor *vi)
-  : _view(vi)
+  : base(vi)
 {
 }
 
@@ -224,11 +222,16 @@ View3DInventorPy::~View3DInventorPy()
         Py_DECREF(*it);
 }
 
+View3DInventor* View3DInventorPy::getView3DIventorPtr()
+{
+    return qobject_cast<View3DInventor*>(base.getMDIViewPtr());
+}
+
 Py::Object View3DInventorPy::repr()
 {
     std::string s;
     std::ostringstream s_out;
-    if (!_view)
+    if (!getView3DIventorPtr())
         throw Py::RuntimeError("Cannot print representation of deleted object");
     s_out << "View3DInventor";
     return Py::String(s_out.str());
@@ -247,28 +250,57 @@ PyObject *View3DInventorPy::method_varargs_ext_handler(PyObject *_self_and_name_
     catch (const std::exception& e) {
         throw Py::RuntimeError(e.what());
     }
+    catch (const Py::Exception&) {
+        throw;
+    }
     catch (...) {
         throw Py::RuntimeError("Unknown C++ exception");
     }
 }
 
+// Since with PyCXX it's not possible to make a sub-class of MDIViewPy
+// a trick is to use MDIViewPy as class member and override getattr() to
+// join the attributes of both classes. This way all methods of MDIViewPy
+// appear for SheetViewPy, too.
+Py::Object View3DInventorPy::getattribute(const char * attr)
+{
+    if (!getView3DIventorPtr())
+        throw Py::RuntimeError("Cannot print representation of deleted object");
+    std::string name( attr );
+    if (name == "__dict__" || name == "__class__") {
+        Py::Dict dict_self(BaseType::getattr("__dict__"));
+        Py::Dict dict_base(base.getattr("__dict__"));
+        for (auto it : dict_base) {
+            dict_self.setItem(it.first, it.second);
+        }
+        return dict_self;
+    }
+
+    try {
+        return BaseType::getattr(attr);
+    }
+    catch (Py::AttributeError& e) {
+        e.clear();
+        return base.getattr(attr);
+    }
+}
+
 Py::Object View3DInventorPy::getattr(const char * attr)
 {
-    if (!_view) {
-        std::string s;
+    if (!getView3DIventorPtr()) {
         std::ostringstream s_out;
         s_out << "Cannot access attribute '" << attr << "' of deleted object";
         throw Py::RuntimeError(s_out.str());
     }
     else {
         // see if an active object has the same name
-        App::DocumentObject *docObj = _view->getActiveObject<App::DocumentObject*>(attr);
+        App::DocumentObject *docObj = getView3DIventorPtr()->getActiveObject<App::DocumentObject*>(attr);
         if (docObj) {
             return Py::Object(docObj->getPyObject(),true);
         }
         else {
             // else looking for a method with the name and call it
-            Py::Object obj = Py::PythonExtension<View3DInventorPy>::getattr(attr);
+            Py::Object obj = getattribute(attr);
             if (PyCFunction_Check(obj.ptr())) {
                 PyCFunctionObject* op = reinterpret_cast<PyCFunctionObject*>(obj.ptr());
                 if (op->m_ml->ml_flags == METH_VARARGS) {
@@ -284,39 +316,17 @@ Py::Object View3DInventorPy::getattr(const char * attr)
 
 int View3DInventorPy::setattr(const char * attr, const Py::Object & value)
 {
-    if (!_view) {
+    if (!getView3DIventorPtr()) {
         std::string s;
         std::ostringstream s_out;
         s_out << "Cannot access attribute '" << attr << "' of deleted object";
         throw Py::RuntimeError(s_out.str());
     }
     else {
-        return Py::PythonExtension<View3DInventorPy>::setattr(attr, value);
+        return BaseType::setattr(attr, value);
     }
 }
 
-Py::Object View3DInventorPy::message(const Py::Tuple& args)
-{
-    const char **ppReturn = 0;
-    char *psMsgStr;
-    if (!PyArg_ParseTuple(args.ptr(), "s;Message string needed (string)",&psMsgStr))     // convert args: Python->C
-        throw Py::Exception();
-
-    try {
-        _view->onMsg(psMsgStr,ppReturn);
-    }
-    catch (const Base::Exception& e) {
-        throw Py::RuntimeError(e.what());
-    }
-    catch (const std::exception& e) {
-        throw Py::RuntimeError(e.what());
-    }
-    catch (...) {
-        throw Py::RuntimeError("Unknown C++ exception");
-    }
-    return Py::None();
-}
-
 Py::Object View3DInventorPy::fitAll(const Py::Tuple& args)
 {
     double factor = 1.0;
@@ -324,7 +334,7 @@ Py::Object View3DInventorPy::fitAll(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->viewAll((float)factor);
+        getView3DIventorPtr()->getViewer()->viewAll((float)factor);
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -347,7 +357,7 @@ Py::Object View3DInventorPy::boxZoom(const Py::Tuple& args, const Py::Dict& kwds
         throw Py::Exception();
 
     SbBox2s box(xmin, ymin, xmax, ymax);
-    _view->getViewer()->boxZoom(box);
+    getView3DIventorPtr()->getViewer()->boxZoom(box);
     return Py::None();
 }
 
@@ -470,7 +480,7 @@ Py::Object View3DInventorPy::viewBottom(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Bottom));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Bottom));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -491,7 +501,7 @@ Py::Object View3DInventorPy::viewFront(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Front));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Front));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -512,7 +522,7 @@ Py::Object View3DInventorPy::viewLeft(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Left));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Left));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -533,7 +543,7 @@ Py::Object View3DInventorPy::viewRear(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Rear));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Rear));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -554,7 +564,7 @@ Py::Object View3DInventorPy::viewRight(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Right));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Right));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -575,7 +585,7 @@ Py::Object View3DInventorPy::viewTop(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Top));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Top));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -596,7 +606,7 @@ Py::Object View3DInventorPy::viewIsometric(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Isometric));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Isometric));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -617,7 +627,7 @@ Py::Object View3DInventorPy::viewDimetric(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Dimetric));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Dimetric));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -638,7 +648,7 @@ Py::Object View3DInventorPy::viewTrimetric(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->setCameraOrientation(Camera::rotation(Camera::Trimetric));
+        getView3DIventorPtr()->getViewer()->setCameraOrientation(Camera::rotation(Camera::Trimetric));
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -707,7 +717,7 @@ Py::Object View3DInventorPy::viewDefaultOrientation(const Py::Tuple& args)
             rot.setValue(q0, q1, q2, q3);
         }
 
-        SoCamera* cam = _view->getViewer()->getCamera();
+        SoCamera* cam = getView3DIventorPtr()->getViewer()->getCamera();
         cam->orientation = rot;
 
         if (scale < 0.0){
@@ -750,7 +760,7 @@ Py::Object View3DInventorPy::viewRotateLeft(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-      SoCamera* cam = _view->getViewer()->getSoRenderManager()->getCamera();
+      SoCamera* cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
       SbRotation rot = cam->orientation.getValue();
       SbVec3f vdir(0, 0, -1);
       rot.multVec(vdir, vdir);
@@ -776,7 +786,7 @@ Py::Object View3DInventorPy::viewRotateRight(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-      SoCamera* cam = _view->getViewer()->getSoRenderManager()->getCamera();
+      SoCamera* cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
       SbRotation rot = cam->orientation.getValue();
       SbVec3f vdir(0, 0, -1);
       rot.multVec(vdir, vdir);
@@ -802,7 +812,7 @@ Py::Object View3DInventorPy::zoomIn(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->navigationStyle()->zoomIn();
+        getView3DIventorPtr()->getViewer()->navigationStyle()->zoomIn();
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -823,7 +833,7 @@ Py::Object View3DInventorPy::zoomOut(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->getViewer()->navigationStyle()->zoomOut();
+        getView3DIventorPtr()->getViewer()->navigationStyle()->zoomOut();
     }
     catch (const Base::Exception& e) {
         throw Py::RuntimeError(e.what());
@@ -852,13 +862,13 @@ Py::Object View3DInventorPy::setCameraOrientation(const Py::Tuple& args)
             float q1 = (float)Py::Float(tuple[1]);
             float q2 = (float)Py::Float(tuple[2]);
             float q3 = (float)Py::Float(tuple[3]);
-            _view->getViewer()->setCameraOrientation(SbRotation(q0, q1, q2, q3), PyObject_IsTrue(m));
+            getView3DIventorPtr()->getViewer()->setCameraOrientation(SbRotation(q0, q1, q2, q3), PyObject_IsTrue(m));
         }
         else if (PyObject_TypeCheck(o, &Base::RotationPy::Type)) {
             Base::Rotation r = (Base::Rotation)Py::Rotation(o,false);
             double q0, q1, q2, q3;
             r.getValue(q0, q1, q2, q3);
-            _view->getViewer()->setCameraOrientation(SbRotation((float)q0, (float)q1, (float)q2, (float)q3), PyObject_IsTrue(m));
+            getView3DIventorPtr()->getViewer()->setCameraOrientation(SbRotation((float)q0, (float)q1, (float)q2, (float)q3), PyObject_IsTrue(m));
         }
         else {
             throw Py::ValueError("Neither tuple nor rotation object");
@@ -884,7 +894,7 @@ Py::Object View3DInventorPy::getCameraOrientation(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    SbRotation rot = _view->getViewer()->getCameraOrientation();
+    SbRotation rot = getView3DIventorPtr()->getViewer()->getCameraOrientation();
     float q0,q1,q2,q3;
     rot.getValue(q0,q1,q2,q3);
     return Py::Rotation(Base::Rotation(q0,q1,q2,q3));
@@ -904,12 +914,12 @@ Py::Object View3DInventorPy::viewPosition(const Py::Tuple& args)
         Base::Vector3d pos = plm->getPosition();
         double q0,q1,q2,q3;
         rot.getValue(q0,q1,q2,q3);
-        _view->getViewer()->moveCameraTo(
+        getView3DIventorPtr()->getViewer()->moveCameraTo(
             SbRotation((float)q0, (float)q1, (float)q2, (float)q3),
             SbVec3f((float)pos.x, (float)pos.y, (float)pos.z), steps, ms);
     }
 
-    SoCamera* cam = _view->getViewer()->getSoRenderManager()->getCamera();
+    SoCamera* cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
     if (!cam) return Py::None();
 
     SbRotation rot = cam->orientation.getValue();
@@ -928,7 +938,7 @@ Py::Object View3DInventorPy::startAnimating(const Py::Tuple& args)
     float velocity;
     if (!PyArg_ParseTuple(args.ptr(), "ffff", &x,&y,&z,&velocity))
         throw Py::Exception();
-    _view->getViewer()->startAnimating(SbVec3f(x,y,z),velocity);
+    getView3DIventorPtr()->getViewer()->startAnimating(SbVec3f(x,y,z),velocity);
     return Py::None();
 }
 
@@ -936,7 +946,7 @@ Py::Object View3DInventorPy::stopAnimating(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    _view->getViewer()->stopAnimating();
+    getView3DIventorPtr()->getViewer()->stopAnimating();
     return Py::None();
 }
 
@@ -945,7 +955,7 @@ Py::Object View3DInventorPy::setAnimationEnabled(const Py::Tuple& args)
     int ok;
     if (!PyArg_ParseTuple(args.ptr(), "i", &ok))
         throw Py::Exception();
-    _view->getViewer()->setAnimationEnabled(ok!=0);
+    getView3DIventorPtr()->getViewer()->setAnimationEnabled(ok!=0);
     return Py::None();
 }
 
@@ -953,7 +963,7 @@ Py::Object View3DInventorPy::isAnimationEnabled(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    SbBool ok = _view->getViewer()->isAnimationEnabled();
+    SbBool ok = getView3DIventorPtr()->getViewer()->isAnimationEnabled();
     return Py::Boolean(ok ? true : false);
 }
 
@@ -962,7 +972,7 @@ Py::Object View3DInventorPy::setPopupMenuEnabled(const Py::Tuple& args)
     int ok;
     if (!PyArg_ParseTuple(args.ptr(), "i", &ok))
         throw Py::Exception();
-    _view->getViewer()->setPopupMenuEnabled(ok!=0);
+    getView3DIventorPtr()->getViewer()->setPopupMenuEnabled(ok!=0);
     return Py::None();
 }
 
@@ -970,7 +980,7 @@ Py::Object View3DInventorPy::isPopupMenuEnabled(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    SbBool ok = _view->getViewer()->isPopupMenuEnabled();
+    SbBool ok = getView3DIventorPtr()->getViewer()->isPopupMenuEnabled();
     return Py::Boolean(ok ? true : false);
 }
 
@@ -998,10 +1008,10 @@ Py::Object View3DInventorPy::saveImage(const Py::Tuple& args)
         bg.setNamedColor(colname);
 
     QImage img;
-    _view->getViewer()->savePicture(w, h, s, bg, img);
+    getView3DIventorPtr()->getViewer()->savePicture(w, h, s, bg, img);
 
     SoFCOffscreenRenderer& renderer = SoFCOffscreenRenderer::instance();
-    SoCamera* cam = _view->getViewer()->getSoRenderManager()->getCamera();
+    SoCamera* cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
     renderer.writeToImageFile(encodedName.c_str(), cComment, cam->getViewVolume().getMatrix(), img);
 
     return Py::None();
@@ -1042,11 +1052,11 @@ Py::Object View3DInventorPy::saveVectorGraphic(const Py::Tuple& args)
     QColor bg;
     QString colname = QString::fromLatin1(name);
     if (colname.compare(QLatin1String("Current"), Qt::CaseInsensitive) == 0)
-        bg = _view->getViewer()->backgroundColor();
+        bg = getView3DIventorPtr()->getViewer()->backgroundColor();
     else
         bg.setNamedColor(colname);
 
-    _view->getViewer()->saveGraphic(ps,bg,vo.get());
+    getView3DIventorPtr()->getViewer()->saveGraphic(ps,bg,vo.get());
     out->closeFile();
     return Py::None();
 }
@@ -1057,7 +1067,7 @@ Py::Object View3DInventorPy::getCameraNode(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        SoNode* camera = _view->getViewer()->getSoRenderManager()->getCamera();
+        SoNode* camera = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
         PyObject* proxy = 0;
         std::string type;
         type = "So"; // seems that So prefix is missing in camera node
@@ -1083,7 +1093,7 @@ Py::Object View3DInventorPy::getCamera(const Py::Tuple& args)
 
     try {
         SoWriteAction wa(&out);
-        SoCamera * cam = _view->getViewer()->getSoRenderManager()->getCamera();
+        SoCamera * cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
         if (cam) wa.apply(cam);
         else buffer[0] = '\0';
         return Py::String(buffer);
@@ -1104,7 +1114,7 @@ Py::Object View3DInventorPy::getViewDirection(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
     try {
-        SbVec3f dvec = _view->getViewer()->getViewDirection();
+        SbVec3f dvec = getView3DIventorPtr()->getViewer()->getViewDirection();
         return Py::Vector(Base::Vector3f(dvec[0], dvec[1], dvec[2]));
     }
     catch (const Base::Exception& e) {
@@ -1134,7 +1144,7 @@ Py::Object View3DInventorPy::setViewDirection(const Py::Tuple& args)
             dir.setValue((float)x, (float)y, (float)z);
             if (dir.length() < 0.001f)
                 throw Py::ValueError("Null vector cannot be used to set direction");
-            _view->getViewer()->setViewDirection(dir);
+            getView3DIventorPtr()->getViewer()->setViewDirection(dir);
             return Py::None();
         }
     }
@@ -1163,7 +1173,7 @@ Py::Object View3DInventorPy::setCamera(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->setCamera(buffer);
+        getView3DIventorPtr()->setCamera(buffer);
         return Py::None();
     }
     catch (const Base::Exception& e) {
@@ -1185,7 +1195,7 @@ Py::Object View3DInventorPy::getCameraType(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
 
-    SoCamera* cam = _view->getViewer()->getSoRenderManager()->getCamera();
+    SoCamera* cam = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera();
     if (!cam) {
         throw Py::RuntimeError("No camera set!");
     }
@@ -1226,9 +1236,9 @@ Py::Object View3DInventorPy::setCameraType(const Py::Tuple& args)
     if (cameratype < 0 || cameratype > 1)
         throw Py::IndexError("Out of range");
     if (cameratype==0)
-        _view->getViewer()->setCameraType(SoOrthographicCamera::getClassTypeId());
+        getView3DIventorPtr()->getViewer()->setCameraType(SoOrthographicCamera::getClassTypeId());
     else
-        _view->getViewer()->setCameraType(SoPerspectiveCamera::getClassTypeId());
+        getView3DIventorPtr()->getViewer()->setCameraType(SoPerspectiveCamera::getClassTypeId());
     return Py::None();
 }
 
@@ -1263,7 +1273,7 @@ Py::Object View3DInventorPy::dump(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->dump(filename, PyObject_IsTrue(onlyVisible));
+        getView3DIventorPtr()->dump(filename, PyObject_IsTrue(onlyVisible));
         return Py::None();
     }
     catch (const Base::Exception& e) {
@@ -1324,7 +1334,7 @@ Py::Object View3DInventorPy::setStereoType(const Py::Tuple& args)
         if (stereomode < 0 || stereomode > 4)
             throw Py::IndexError("Out of range");
         Quarter::SoQTQuarterAdaptor::StereoMode mode = Quarter::SoQTQuarterAdaptor::StereoMode(stereomode);
-        _view->getViewer()->setStereoMode(mode);
+        getView3DIventorPtr()->getViewer()->setStereoMode(mode);
         return Py::None();
     }
     catch (const Base::Exception& e) {
@@ -1344,7 +1354,7 @@ Py::Object View3DInventorPy::getStereoType(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        int mode = (int)(_view->getViewer()->stereoMode());
+        int mode = (int)(getView3DIventorPtr()->getViewer()->stereoMode());
         return Py::String(StereoTypeEnums[mode]);
     }
     catch (const Base::Exception& e) {
@@ -1387,10 +1397,10 @@ Py::Object View3DInventorPy::getCursorPos(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
     try {
-        QPoint pos = _view->mapFromGlobal(QCursor::pos());
+        QPoint pos = getView3DIventorPtr()->mapFromGlobal(QCursor::pos());
         Py::Tuple tuple(2);
         tuple.setItem(0, Py::Int(pos.x()));
-        tuple.setItem(1, Py::Int(_view->height()-pos.y()-1));
+        tuple.setItem(1, Py::Int(getView3DIventorPtr()->height()-pos.y()-1));
         return tuple;
     }
     catch (const Py::Exception&) {
@@ -1401,7 +1411,7 @@ Py::Object View3DInventorPy::getCursorPos(const Py::Tuple& args)
 Py::Object View3DInventorPy::getObjectInfo(const Py::Tuple& args)
 {
     PyObject* object;
-    float r = _view->getViewer()->getPickRadius();
+    float r = getView3DIventorPtr()->getViewer()->getPickRadius();
     if (!PyArg_ParseTuple(args.ptr(), "O|f", &object, &r))
         throw Py::Exception();
 
@@ -1419,10 +1429,10 @@ Py::Object View3DInventorPy::getObjectInfo(const Py::Tuple& args)
         // graph traversal we must not use a second SoHandleEventAction as
         // we will get Coin warnings because of multiple scene graph traversals
         // which is regarded as error-prone.
-        SoRayPickAction action(_view->getViewer()->getSoRenderManager()->getViewportRegion());
+        SoRayPickAction action(getView3DIventorPtr()->getViewer()->getSoRenderManager()->getViewportRegion());
         action.setPoint(SbVec2s((long)x,(long)y));
         action.setRadius(r);
-        action.apply(_view->getViewer()->getSoRenderManager()->getSceneGraph());
+        action.apply(getView3DIventorPtr()->getViewer()->getSoRenderManager()->getSceneGraph());
         SoPickedPoint *Point = action.getPickedPoint();
 
         Py::Object ret = Py::None();
@@ -1433,9 +1443,9 @@ Py::Object View3DInventorPy::getObjectInfo(const Py::Tuple& args)
             dict.setItem("y", Py::Float(pt[1]));
             dict.setItem("z", Py::Float(pt[2]));
 
-            Gui::Document* doc = _view->getViewer()->getDocument();
+            Gui::Document* doc = getView3DIventorPtr()->getViewer()->getDocument();
             ViewProvider *vp = doc ? doc->getViewProviderByPathFromHead(Point->getPath())
-                    : _view->getViewer()->getViewProviderByPath(Point->getPath());
+                    : getView3DIventorPtr()->getViewer()->getViewProviderByPath(Point->getPath());
             if (vp && vp->isDerivedFrom(ViewProviderDocumentObject::getClassTypeId())) {
                 if (!vp->isSelectable())
                     return ret;
@@ -1509,7 +1519,7 @@ Py::Object View3DInventorPy::getObjectInfo(const Py::Tuple& args)
 Py::Object View3DInventorPy::getObjectsInfo(const Py::Tuple& args)
 {
     PyObject* object;
-    float r = _view->getViewer()->getPickRadius();
+    float r = getView3DIventorPtr()->getViewer()->getPickRadius();
     if (!PyArg_ParseTuple(args.ptr(), "O|f", &object, &r))
         throw Py::Exception();
 
@@ -1527,14 +1537,14 @@ Py::Object View3DInventorPy::getObjectsInfo(const Py::Tuple& args)
         // graph traversal we must not use a second SoHandleEventAction as
         // we will get Coin warnings because of multiple scene graph traversals
         // which is regarded as error-prone.
-        SoRayPickAction action(_view->getViewer()->getSoRenderManager()->getViewportRegion());
+        SoRayPickAction action(getView3DIventorPtr()->getViewer()->getSoRenderManager()->getViewportRegion());
         action.setPickAll(true);
         action.setRadius(r);
         action.setPoint(SbVec2s((long)x,(long)y));
-        action.apply(_view->getViewer()->getSoRenderManager()->getSceneGraph());
+        action.apply(getView3DIventorPtr()->getViewer()->getSoRenderManager()->getSceneGraph());
         const SoPickedPointList& pp = action.getPickedPointList();
 
-        Gui::Document* doc = _view->getViewer()->getDocument();
+        Gui::Document* doc = getView3DIventorPtr()->getViewer()->getDocument();
         Py::Object ret = Py::None();
         if (pp.getLength() > 0) {
             Py::List list;
@@ -1547,7 +1557,7 @@ Py::Object View3DInventorPy::getObjectsInfo(const Py::Tuple& args)
                 dict.setItem("z", Py::Float(pt[2]));
 
                 ViewProvider *vp = doc ? doc->getViewProviderByPathFromHead(point->getPath())
-                        : _view->getViewer()->getViewProviderByPath(point->getPath());
+                        : getView3DIventorPtr()->getViewer()->getViewProviderByPath(point->getPath());
                 if(vp && vp->isDerivedFrom(ViewProviderDocumentObject::getClassTypeId())) {
                     if(!vp->isSelectable())
                         continue;
@@ -1625,7 +1635,7 @@ Py::Object View3DInventorPy::getSize(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
     try {
-        SbVec2s size = _view->getViewer()->getSoRenderManager()->getSize();
+        SbVec2s size = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getSize();
         Py::Tuple tuple(2);
         tuple.setItem(0, Py::Int(size[0]));
         tuple.setItem(1, Py::Int(size[1]));
@@ -1646,7 +1656,7 @@ Py::Object View3DInventorPy::getPoint(const Py::Tuple& args)
         y = (int)Py::Int(t[1]);
     }
     try {
-        SbVec3f pt = _view->getViewer()->getPointOnScreen(SbVec2s(x,y));
+        SbVec3f pt = getView3DIventorPtr()->getViewer()->getPointOnScreen(SbVec2s(x,y));
         return Py::Vector(Base::Vector3f(pt[0], pt[1], pt[2]));
     }
     catch (const Base::Exception& e) {
@@ -1675,11 +1685,11 @@ Py::Object View3DInventorPy::getPointOnScreen(const Py::Tuple& args)
     }
 
     try {
-        const SbViewportRegion& vp = _view->getViewer()->getSoRenderManager()->getViewportRegion();
+        const SbViewportRegion& vp = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getViewportRegion();
         float fRatio = vp.getViewportAspectRatio();
         const SbVec2s& sp = vp.getViewportSizePixels();
         //float dX, dY; vp.getViewportSize().getValue(dX, dY);
-        SbViewVolume vv = _view->getViewer()->getSoRenderManager()->getCamera()->getViewVolume(fRatio);
+        SbViewVolume vv = getView3DIventorPtr()->getViewer()->getSoRenderManager()->getCamera()->getViewVolume(fRatio);
 
         SbVec3f pt(vx,vy,vz);
         vv.projectToScreen(pt, pt);
@@ -1720,7 +1730,7 @@ Py::Object View3DInventorPy::listNavigationTypes(const Py::Tuple&)
 
 Py::Object View3DInventorPy::getNavigationType(const Py::Tuple&)
 {
-    std::string name = _view->getViewer()->navigationStyle()->getTypeId().getName();
+    std::string name = getView3DIventorPtr()->getViewer()->navigationStyle()->getTypeId().getName();
     return Py::String(name);
 }
 
@@ -1730,7 +1740,7 @@ Py::Object View3DInventorPy::setNavigationType(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), "s", &style))
         throw Py::Exception();
     Base::Type type = Base::Type::fromName(style);
-    _view->getViewer()->setNavigationType(type);
+    getView3DIventorPtr()->getViewer()->setNavigationType(type);
     return Py::None();
 }
 
@@ -2111,7 +2121,7 @@ Py::Object View3DInventorPy::addEventCallback(const Py::Tuple& args)
             throw Py::TypeError(s_out.str());
         }
 
-        _view->getViewer()->addEventCallback(eventId, View3DInventorPy::eventCallback, method);
+        getView3DIventorPtr()->getViewer()->addEventCallback(eventId, View3DInventorPy::eventCallback, method);
         callbacks.push_back(method);
         Py_INCREF(method);
         return Py::Callable(method, false);
@@ -2139,7 +2149,7 @@ Py::Object View3DInventorPy::removeEventCallback(const Py::Tuple& args)
             throw Py::TypeError(s_out.str());
         }
 
-        _view->getViewer()->removeEventCallback(eventId, View3DInventorPy::eventCallback, method);
+        getView3DIventorPtr()->getViewer()->removeEventCallback(eventId, View3DInventorPy::eventCallback, method);
         callbacks.remove(method);
         Py_DECREF(method);
         return Py::None();
@@ -2164,7 +2174,7 @@ Py::Object View3DInventorPy::setAnnotation(const Py::Tuple& args)
         throw Py::RuntimeError(e.what());
     }
 
-    _view->getGuiDocument()->setAnnotationViewProvider(psAnnoName, view);
+    getView3DIventorPtr()->getGuiDocument()->setAnnotationViewProvider(psAnnoName, view);
     return Py::None();
 }
 
@@ -2174,9 +2184,9 @@ Py::Object View3DInventorPy::removeAnnotation(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), "s", &psAnnoName))
         throw Py::Exception();
     ViewProvider* view = 0;
-    view = _view->getGuiDocument()->getAnnotationViewProvider(psAnnoName);
+    view = getView3DIventorPtr()->getGuiDocument()->getAnnotationViewProvider(psAnnoName);
     if (view) {
-        _view->getGuiDocument()->removeAnnotationViewProvider(psAnnoName);
+        getView3DIventorPtr()->getGuiDocument()->removeAnnotationViewProvider(psAnnoName);
         return Py::None();
     }
     else {
@@ -2193,7 +2203,7 @@ Py::Object View3DInventorPy::getSceneGraph(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        SoNode* scene = _view->getViewer()->getSceneGraph();
+        SoNode* scene = getView3DIventorPtr()->getViewer()->getSceneGraph();
         PyObject* proxy = 0;
         proxy = Base::Interpreter().createSWIGPointerObj("pivy.coin", "SoSeparator *", (void*)scene, 1);
         scene->ref();
@@ -2209,7 +2219,7 @@ Py::Object View3DInventorPy::getViewer(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
 
-    View3DInventorViewer* viewer = _view->getViewer();
+    View3DInventorViewer* viewer = getView3DIventorPtr()->getViewer();
     return Py::Object(viewer->getPyObject(), true);
 }
 
@@ -2313,7 +2323,7 @@ Py::Object View3DInventorPy::addEventCallbackPivy(const Py::Tuple& args)
         SoEventCallbackCB* callback = (ex == 1 ?
             View3DInventorPy::eventCallbackPivyEx :
             View3DInventorPy::eventCallbackPivy);
-        _view->getViewer()->addEventCallback(*eventId, callback, method);
+        getView3DIventorPtr()->getViewer()->addEventCallback(*eventId, callback, method);
         callbacks.push_back(method);
         Py_INCREF(method);
         return Py::Callable(method, false);
@@ -2355,7 +2365,7 @@ Py::Object View3DInventorPy::removeEventCallbackPivy(const Py::Tuple& args)
         SoEventCallbackCB* callback = (ex == 1 ?
             View3DInventorPy::eventCallbackPivyEx :
             View3DInventorPy::eventCallbackPivy);
-        _view->getViewer()->removeEventCallback(*eventId, callback, method);
+        getView3DIventorPtr()->getViewer()->removeEventCallback(*eventId, callback, method);
         callbacks.remove(method);
         Py_DECREF(method);
         return Py::Callable(method, false);
@@ -2370,7 +2380,7 @@ Py::Object View3DInventorPy::setAxisCross(const Py::Tuple& args)
     int ok;
     if (!PyArg_ParseTuple(args.ptr(), "i", &ok))
         throw Py::Exception();
-    _view->getViewer()->setAxisCross(ok!=0);
+    getView3DIventorPtr()->getViewer()->setAxisCross(ok!=0);
     return Py::None();
 }
 
@@ -2378,7 +2388,7 @@ Py::Object View3DInventorPy::hasAxisCross(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    SbBool ok = _view->getViewer()->hasAxisCross();
+    SbBool ok = getView3DIventorPtr()->getViewer()->hasAxisCross();
     return Py::Boolean(ok ? true : false);
 }
 
@@ -2522,13 +2532,13 @@ Py::Object View3DInventorPy::setActiveObject(const Py::Tuple& args)
         throw Py::Exception();
 
     if (docObject == Py_None) {
-        _view->setActiveObject(0, name);
+        getView3DIventorPtr()->setActiveObject(0, name);
     }
     else {
         if (!PyObject_TypeCheck(docObject, &App::DocumentObjectPy::Type))
             throw Py::TypeError("Expect the second argument to be a document object or None");
         App::DocumentObject* obj = static_cast<App::DocumentObjectPy*>(docObject)->getDocumentObjectPtr();
-        _view->setActiveObject(obj, name, subname);
+        getView3DIventorPtr()->setActiveObject(obj, name, subname);
     }
 
     return Py::None();
@@ -2543,7 +2553,7 @@ Py::Object View3DInventorPy::getActiveObject(const Py::Tuple& args)
 
     App::DocumentObject *parent = 0;
     std::string subname;
-    App::DocumentObject* obj = _view->getActiveObject<App::DocumentObject*>(name,&parent,&subname);
+    App::DocumentObject* obj = getView3DIventorPtr()->getActiveObject<App::DocumentObject*>(name,&parent,&subname);
     if (!obj)
         return Py::None();
 
@@ -2562,7 +2572,7 @@ Py::Object View3DInventorPy::getViewProvidersOfType(const Py::Tuple& args)
     if (!PyArg_ParseTuple(args.ptr(), "s", &name))
         throw Py::Exception();
 
-    std::vector<ViewProvider*> vps = _view->getViewer()->getViewProvidersOfType(Base::Type::fromName(name));
+    std::vector<ViewProvider*> vps = getView3DIventorPtr()->getViewer()->getViewProvidersOfType(Base::Type::fromName(name));
     Py::List list;
     for (std::vector<ViewProvider*>::iterator it = vps.begin(); it != vps.end(); ++it) {
         list.append(Py::asObject((*it)->getPyObject()));
@@ -2575,7 +2585,7 @@ Py::Object View3DInventorPy::redraw(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    _view->getViewer()->redraw();
+    getView3DIventorPtr()->getViewer()->redraw();
     return Py::None();
 }
 
@@ -2586,7 +2596,7 @@ Py::Object View3DInventorPy::setName(const Py::Tuple& args)
         throw Py::Exception();
 
     try {
-        _view->setWindowTitle(QString::fromUtf8(buffer));
+        getView3DIventorPtr()->setWindowTitle(QString::fromUtf8(buffer));
         return Py::None();
     }
     catch (const Base::Exception& e) {
@@ -2614,7 +2624,7 @@ Py::Object View3DInventorPy::toggleClippingPlane(const Py::Tuple& args, const Py
     Base::Placement pla;
     if(pyPla!=Py_None)
         pla = *static_cast<Base::PlacementPy*>(pyPla)->getPlacementPtr();
-    _view->getViewer()->toggleClippingPlane(toggle,PyObject_IsTrue(beforeEditing),
+    getView3DIventorPtr()->getViewer()->toggleClippingPlane(toggle,PyObject_IsTrue(beforeEditing),
             PyObject_IsTrue(noManip),pla);
     return Py::None();
 }
@@ -2623,7 +2633,7 @@ Py::Object View3DInventorPy::hasClippingPlane(const Py::Tuple& args)
 {
     if (!PyArg_ParseTuple(args.ptr(), ""))
         throw Py::Exception();
-    return Py::Boolean(_view->getViewer()->hasClippingPlane());
+    return Py::Boolean(getView3DIventorPtr()->getViewer()->hasClippingPlane());
 }
 
 Py::Object View3DInventorPy::graphicsView(const Py::Tuple& args)
@@ -2633,10 +2643,10 @@ Py::Object View3DInventorPy::graphicsView(const Py::Tuple& args)
 
     PythonWrapper wrap;
     wrap.loadWidgetsModule();
-    return wrap.fromQWidget(_view->getViewer(), "QGraphicsView");
+    return wrap.fromQWidget(getView3DIventorPtr()->getViewer(), "QGraphicsView");
 }
 
 Py::Object View3DInventorPy::cast_to_base(const Py::Tuple&)
 {
-    return Gui::MDIViewPy::create(_view);
+    return Gui::MDIViewPy::create(getView3DIventorPtr());
 }
diff --git a/src/Gui/View3DPy.h b/src/Gui/View3DPy.h
index 9bc057bfb4..9a7bf17148 100644
--- a/src/Gui/View3DPy.h
+++ b/src/Gui/View3DPy.h
@@ -26,6 +26,8 @@
 
 #include <Base/PyObjectBase.h>
 #include <CXX/Extensions.hxx>
+#include <Gui/MDIView.h>
+#include <Gui/MDIViewPy.h>
 
 class SoEventCallback;
 class SoDragger;
@@ -56,16 +58,18 @@ public:
 class View3DInventorPy : public Py::PythonExtension<View3DInventorPy>
 {
 public:
-    static void init_type(void);    // announce properties and methods
+    using BaseType = Py::PythonExtension<View3DInventorPy>;
+    static void init_type();    // announce properties and methods
 
     View3DInventorPy(View3DInventor *vi);
     ~View3DInventorPy();
 
+    View3DInventor* getView3DIventorPtr();
     Py::Object repr();
     Py::Object getattr(const char *);
     int setattr(const char *, const Py::Object &);
+    Py::Object cast_to_base(const Py::Tuple&);
 
-    Py::Object message(const Py::Tuple&);
     Py::Object fitAll(const Py::Tuple&);
     Py::Object boxZoom(const Py::Tuple&, const Py::Dict&);
     Py::Object viewBottom(const Py::Tuple&);
@@ -135,9 +139,6 @@ public:
     Py::Object toggleClippingPlane(const Py::Tuple& args, const Py::Dict &);
     Py::Object hasClippingPlane(const Py::Tuple& args);
     Py::Object graphicsView(const Py::Tuple& args);
-    Py::Object cast_to_base(const Py::Tuple&);
-
-    View3DInventor* getView3DIventorPtr() {return _view;}
 
 private:
     static void eventCallback(void * ud, SoEventCallback * n);
@@ -149,11 +150,11 @@ private:
     typedef PyObject* (*method_varargs_handler)(PyObject *_self, PyObject *_args);
     static method_varargs_handler pycxx_handler;
     static PyObject *method_varargs_ext_handler(PyObject *_self, PyObject *_args);
+    Py::Object getattribute(const char *);
 
 private:
+    Gui::MDIViewPy base;
     std::list<PyObject*> callbacks;
-    View3DInventor* _view;
-    friend class View3DInventor;
 };
 
 } // namespace Gui