Message_ProgressScope aPS(theRange, NULL, 1);
    if (!aPS.More())
    {
      aDFace->SetStatus(IMeshData_UserBreak);
      return;
    }
    aMeshingAlgo->Perform(aDFace, myParameters, aPS.Next());

+    if (!aPS.More())
+    {
+      return;
+    }
 
     if (this->getParameters().ControlSurfaceDeflection &&
-        this->getStructure()->ElementsOfDomain().Extent() > 0)
+        this->getStructure()->ElementsOfDomain().Extent() > 0 &&
+        aPS.More())
+    {
+      optimizeMesh(theMesher, aPS.Next());
+    }
+    else
     {
-      optimizeMesh(theMesher);
+      aPS.Next();
     }

-  virtual void postProcessMesh(BRepMesh_Delaun& theMesher) Standard_OVERRIDE
+  virtual void postProcessMesh (BRepMesh_Delaun& theMesher, 
+                                const Message_ProgressRange& theRange = Message_ProgressRange()) 
Standard_OVERRIDE
...
   //! Inserts nodes into mesh.
   Standard_Boolean insertNodes(
     const Handle(IMeshData::ListOfPnt2d)& theNodes,
-    BRepMesh_Delaun&                      theMesher)
+    BRepMesh_Delaun&                      theMesher,
+    const Message_ProgressRange&          theRange = Message_ProgressRange())
...
   Standard_EXPORT virtual Standard_Boolean performInternal (
     const Handle (IMeshData_Model)& theModel,
-    const IMeshTools_Parameters&    theParameters) Standard_OVERRIDE;
+    const IMeshTools_Parameters&    theParameters,
+    const Message_ProgressRange&    theRange = Message_ProgressRange()) Standard_OVERRIDE;

-  OSD_Parallel::For(0, myModel->FacesNb(), *this, !(myParameters.InParallel && myModel->FacesNb() 
> 1));
...
+  std::vector<FaceScope> aSF;
+  OSD_Parallel::ForEach(aSF.begin(), aSF.end(), *this, !(myParameters.InParallel && myModel->FacesNb() 
> 1));

   Standard_EXPORT virtual Standard_Boolean performInternal (
     const Handle (IMeshData_Model)& theModel,
-    const IMeshTools_Parameters&    theParameters) Standard_OVERRIDE;
+    const IMeshTools_Parameters&    theParameters,
+    const Message_ProgressRange&    theRange = Message_ProgressRange()) Standard_OVERRIDE;

+  void process(const Standard_Integer theFaceIndex, 
+               const Message_ProgressRange& theRange = Message_ProgressRange()) const;