add method to get self-intersections of a mesh via Python

src/Mod/Mesh/App/MeshPy.xml

@@ -230,6 +230,11 @@ for c in mesh.getSeparatecomponents():
 				<UserDocu>Check if the mesh intersects itself</UserDocu>
 			</Documentation>
 		</Methode>
+        <Methode Name="getSelfIntersections" Const="true">
+            <Documentation>
+                <UserDocu>Returns a tuple of indices of intersecting triangles</UserDocu>
+            </Documentation>
+        </Methode>
         <Methode Name="fixSelfIntersections">
 			<Documentation>
 				<UserDocu>Repair self-intersections</UserDocu>

src/Mod/Mesh/App/MeshPyImp.cpp

@@ -583,7 +583,15 @@ PyObject*  MeshPy::addFacet(PyObject *args)
         Py_Return;
     }
 
-    PyErr_SetString(Base::BaseExceptionFreeCADError, "set 9 floats or three vectors");
+    PyErr_Clear();
+    PyObject *f;
+    if (PyArg_ParseTuple(args, "O!",&(Mesh::FacetPy::Type), &f)) {
+        Mesh::FacetPy* face = static_cast<Mesh::FacetPy*>(f);
+        getMeshObjectPtr()->addFacet(*face->getFacetPtr());
+        Py_Return;
+    }
+
+    PyErr_SetString(Base::BaseExceptionFreeCADError, "set 9 floats or three vectors or a facet");
     return 0;
 }
 
@@ -921,6 +929,32 @@ PyObject*  MeshPy::hasSelfIntersections(PyObject *args)
     return Py_BuildValue("O", (ok ? Py_True : Py_False)); 
 }
 
+PyObject*  MeshPy::getSelfIntersections(PyObject *args)
+{
+    if (!PyArg_ParseTuple(args, ""))
+        return NULL;
+
+    std::vector<std::pair<unsigned long, unsigned long> > selfIndices;
+    std::vector<std::pair<Base::Vector3f, Base::Vector3f> > selfPoints;
+    MeshCore::MeshEvalSelfIntersection eval(getMeshObjectPtr()->getKernel());
+    eval.GetIntersections(selfIndices);
+    eval.GetIntersections(selfIndices, selfPoints);
+
+    Py::Tuple tuple(selfIndices.size());
+    if (selfIndices.size() == selfPoints.size()) {
+        for (std::size_t i=0; i<selfIndices.size(); i++) {
+            Py::Tuple item(4);
+            item.setItem(0, Py::Long(selfIndices[i].first));
+            item.setItem(1, Py::Long(selfIndices[i].second));
+            item.setItem(2, Py::Vector(selfPoints[i].first));
+            item.setItem(3, Py::Vector(selfPoints[i].second));
+            tuple.setItem(i, item);
+        }
+    }
+
+    return Py::new_reference_to(tuple);
+}
+
 PyObject*  MeshPy::fixSelfIntersections(PyObject *args)
 {
     if (!PyArg_ParseTuple(args, ""))