diff --git a/src/Mod/Path/App/Voronoi.cpp b/src/Mod/Path/App/Voronoi.cpp
index b24191d401..96442ede5e 100644
--- a/src/Mod/Path/App/Voronoi.cpp
+++ b/src/Mod/Path/App/Voronoi.cpp
@@ -43,28 +43,24 @@ TYPESYSTEM_SOURCE(Path::Voronoi , Base::BaseClass);
 
 // Helpers
 
-#if 0
-static const std::size_t EXTERNAL_COLOR = 1;
-
-static void color_exterior(const Voronoi::diagram_type::edge_type *edge) {
-  if (edge->color() == EXTERNAL_COLOR) {
+static void colorExterior(const Voronoi::diagram_type::edge_type *edge, std::size_t colorValue) {
+  if (edge->color() == colorValue) {
     // end recursion
     return;
   }
-  edge->color(EXTERNAL_COLOR);
-  edge->twin()->color(EXTERNAL_COLOR);
+  edge->color(colorValue);
+  edge->twin()->color(colorValue);
   auto v = edge->vertex1();
   if (v == NULL || !edge->is_primary()) {
     return;
   }
-  v->color(EXTERNAL_COLOR);
+  v->color(colorValue);
   auto e = v->incident_edge();
   do {
-    color_exterior(e);
+    colorExterior(e, colorValue);
     e = e->rot_next();
   } while (e != v->incident_edge());
 }
-#endif
 
 // Constructors & destructors
 
@@ -147,3 +143,22 @@ void Voronoi::construct()
   construct_voronoi(vd->points.begin(), vd->points.end(), vd->segments.begin(), vd->segments.end(), (voronoi_diagram_type*)vd);
   vd->reIndex();
 }
+
+void Voronoi::colorExterior(int color) {
+  for (diagram_type::const_edge_iterator it = vd->edges().begin(); it != vd->edges().end(); ++it) {
+    if (!it->is_finite()) {
+      ::colorExterior(&(*it), color);
+    }
+  }
+}
+
+void Voronoi::colorTwins(int color) {
+  for (diagram_type::const_edge_iterator it = vd->edges().begin(); it != vd->edges().end(); ++it) {
+    if (!it->color()) {
+      auto twin = it->twin();
+      if (!twin->color()) {
+        twin->color(color);
+      }
+    }
+  }
+}
diff --git a/src/Mod/Path/App/Voronoi.h b/src/Mod/Path/App/Voronoi.h
index 5be8018170..586d8e0b23 100644
--- a/src/Mod/Path/App/Voronoi.h
+++ b/src/Mod/Path/App/Voronoi.h
@@ -89,8 +89,13 @@ namespace Path
     long numEdges() const;
     long numVertices() const;
 
+    void colorExterior(int color);
+    void colorTwins(int color);
+
+  private:
     // attributes
     Base::Reference<diagram_type> vd;
+    friend class VoronoiPy;
   };
 
 } //namespace Path
diff --git a/src/Mod/Path/App/VoronoiPy.xml b/src/Mod/Path/App/VoronoiPy.xml
index b38bf6872b..b6227aaf01 100644
--- a/src/Mod/Path/App/VoronoiPy.xml
+++ b/src/Mod/Path/App/VoronoiPy.xml
@@ -63,5 +63,15 @@
                 <UserDocu>constructs the voronoi diagram from the input collections</UserDocu>
             </Documentation>
         </Methode>
+        <Methode Name="colorExterior">
+            <Documentation>
+                <UserDocu>assign given color to all exterior edges and vertices</UserDocu>
+            </Documentation>
+        </Methode>
+        <Methode Name="colorTwins">
+            <Documentation>
+                <UserDocu>assign given color to all twins of edges (which one is considered a twin is arbitrary)</UserDocu>
+            </Documentation>
+        </Methode>
     </PythonExport>
 </GenerateModel>
diff --git a/src/Mod/Path/App/VoronoiPyImp.cpp b/src/Mod/Path/App/VoronoiPyImp.cpp
index 403961fc2e..6c0bd9eafd 100644
--- a/src/Mod/Path/App/VoronoiPyImp.cpp
+++ b/src/Mod/Path/App/VoronoiPyImp.cpp
@@ -169,6 +169,28 @@ Py::List VoronoiPy::getCells(void) const {
   return list;
 }
 
+PyObject* VoronoiPy::colorExterior(PyObject *args) {
+  int color = 0;
+  if (!PyArg_ParseTuple(args, "i", &color)) {
+    throw  Py::RuntimeError("colorExterior requires an integer (color) argument");
+  }
+  getVoronoiPtr()->colorExterior(color);
+
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
+PyObject* VoronoiPy::colorTwins(PyObject *args) {
+  int color = 0;
+  if (!PyArg_ParseTuple(args, "i", &color)) {
+    throw  Py::RuntimeError("colorTwins requires an integer (color) argument");
+  }
+  getVoronoiPtr()->colorTwins(color);
+
+  Py_INCREF(Py_None);
+  return Py_None;
+}
+
 // custom attributes get/set
 
 PyObject *VoronoiPy::getCustomAttributes(const char* /*attr*/) const