Fem: Implement basic python filter functionality and glyph example

src/Mod/Fem/App/PropertyPostDataObject.cpp

@@ -42,6 +42,10 @@
 #include <vtkXMLUnstructuredGridReader.h>
 #endif
 
+#ifdef BUILD_FEM_VTK_WRAPPER
+#include <vtkPythonUtil.h>
+#endif
+
 #include <App/Application.h>
 #include <App/DocumentObject.h>
 #include <Base/Console.h>
@@ -162,12 +166,26 @@ int PropertyPostDataObject::getDataType()
 
 PyObject* PropertyPostDataObject::getPyObject()
 {
-    // TODO: fetch the vtk python object from the data set and return it
-    return Py::new_reference_to(Py::None());
+#ifdef BUILD_FEM_VTK_WRAPPER
+    //create a copy first
+    auto copy = static_cast<PropertyPostDataObject*>(Copy());
+
+    // get the data python wrapper
+    PyObject* py_dataset = vtkPythonUtil::GetObjectFromPointer(copy->getValue());
+    auto result =  Py::new_reference_to(py_dataset);
+    delete copy;
+
+    return result;
+#else
+    PyErr_SetString(PyExc_NotImplementedError, "VTK python wrapper not available");
+    Py_Return;
+#endif
 }
 
 void PropertyPostDataObject::setPyObject(PyObject* /*value*/)
-{}
+{
+    throw Base::NotImplementedError();
+}
 
 App::Property* PropertyPostDataObject::Copy() const
 {