diff --git a/src/Mod/Part/App/TopoShape.cpp b/src/Mod/Part/App/TopoShape.cpp
index 6ef33e341..31d8a3d49 100644
--- a/src/Mod/Part/App/TopoShape.cpp
+++ b/src/Mod/Part/App/TopoShape.cpp
@@ -678,7 +678,7 @@ void TopoShape::write(const char *FileName) const
     }
     else if (File.hasExtension("stl")) {
         // read brep-file
-        exportStl(File.filePath().c_str());
+        exportStl(File.filePath().c_str(),0);
     }
     else{
         throw Base::Exception("Unknown extension");
@@ -754,11 +754,13 @@ void TopoShape::dump(std::ostream& out) const
     BRepTools::Dump(this->_Shape, out);
 }
 
-void TopoShape::exportStl(const char *filename) const
+void TopoShape::exportStl(const char *filename, double deflection) const
 {
     StlAPI_Writer writer;
-    //writer.RelativeMode() = false;
-    //writer.SetDeflection(0.1);
+    if (deflection > 0) {
+        writer.RelativeMode() = false;
+        writer.SetDeflection(deflection);
+    }
     QString fn = QString::fromUtf8(filename);
     writer.Write(this->_Shape,(const Standard_CString)fn.toLocal8Bit());
 }
diff --git a/src/Mod/Part/App/TopoShape.h b/src/Mod/Part/App/TopoShape.h
index 30a10ce82..2f9067b04 100644
--- a/src/Mod/Part/App/TopoShape.h
+++ b/src/Mod/Part/App/TopoShape.h
@@ -128,7 +128,7 @@ public:
     void exportStep(const char *FileName) const;
     void exportBrep(const char *FileName) const;
     void exportBrep(std::ostream&) const;
-    void exportStl (const char *FileName) const;
+    void exportStl (const char *FileName, double deflection) const;
     void exportFaceSet(double, double, std::ostream&) const;
     void exportLineSet(std::ostream&) const;
     //@}
diff --git a/src/Mod/Part/App/TopoShapePyImp.cpp b/src/Mod/Part/App/TopoShapePyImp.cpp
index b146180ac..8c70c5009 100644
--- a/src/Mod/Part/App/TopoShapePyImp.cpp
+++ b/src/Mod/Part/App/TopoShapePyImp.cpp
@@ -424,12 +424,13 @@ PyObject*  TopoShapePy::importBrepFromString(PyObject *args)
 PyObject*  TopoShapePy::exportStl(PyObject *args)
 {
     char* filename;
-    if (!PyArg_ParseTuple(args, "s", &filename))
+    double deflection = 0;
+    if (!PyArg_ParseTuple(args, "s|d", &filename, &deflection))
         return NULL;
 
     try {
         // write stl file
-        getTopoShapePtr()->exportStl(filename);
+        getTopoShapePtr()->exportStl(filename, deflection);
     }
     catch (const Base::Exception& e) {
         PyErr_SetString(PyExc_Exception,e.what());