-void StdPrs_ShadedShape::Tessellate (const TopoDS_Shape&          theShape,
-                                     const Handle (Prs3d_Drawer)& theDrawer)
-{
-  // Check if it is possible to avoid unnecessary recomputation of shape triangulation
-  Standard_Real aDeflection = Prs3d::GetDeflection (theShape, theDrawer);
-  if (BRepTools::Triangulation (theShape, aDeflection))
-  {
-    return;
-  }
-
-  // retrieve meshing tool from Factory
-  Handle(BRepMesh_DiscretRoot) aMeshAlgo = BRepMesh_DiscretFactory::Get().Discret (theShape,
-                                                                                   aDeflection,
-                                                                                   theDrawer->HLRAngle());
-  if (!aMeshAlgo.IsNull())
-  {
-    aMeshAlgo->Perform();
-  }
+void StdPrs_ToolTriangulatedShape::Tessellate (const TopoDS_Shape&         theShape,
+                                               const Handle(Prs3d_Drawer)& theDrawer)
+{
+  // Check if it is possible to avoid unnecessary recomputation of shape triangulation
+  if (IsTessellated (theShape, theDrawer))
+  {
+    return;
+  }
+
+  Standard_Real aDeflection = Prs3d::GetDeflection (theShape, theDrawer);
+
+  // retrieve meshing tool from Factory
+  BRepTools::Clean (theShape); <<<
+  Handle(BRepMesh_DiscretRoot) aMeshAlgo = BRepMesh_DiscretFactory::Get().Discret (theShape,
+                                                                                   aDeflection,
+                                                                                   theDrawer->HLRAngle());
+  if (!aMeshAlgo.IsNull())
+  {
+    aMeshAlgo->Perform();
+  }
+}

@@ -320,7 +320,17 @@ void AIS_ColoredShape::Compute (const Handle(PrsMgr_PresentationManager3d)& ,
       }
       // After this call if type of deflection is relative
       // computed deflection coefficient is stored as absolute.
-      StdPrs_ShadedShape::Tessellate (myshape, myDrawer);
+      StdPrs_ToolTriangulatedShape::Tessellate (myshape, myDrawer);
+    }
+    if (!StdPrs_ToolTriangulatedShape::IsTessellated (myshape, myDrawer))
+    {
+      StdPrs_ToolTriangulatedShape::Tessellate (myshape, myDrawer);
+
+      // Set to update wireframe presentation on triangulation.
+      if (myDrawer->IsoOnTriangulation())
+      {
+        SetToUpdate (AIS_WireFrame);
+      }

@@ -176,42 +188,68 @@ void AIS_Shape::Compute(const Handle(PrsMgr_PresentationManager3d)& /*aPresentat
           BRepTools::Clean (myshape);
         }
       }
+      if (!StdPrs_ToolTriangulatedShape::IsTessellated (myshape, myDrawer))
+      {
+        StdPrs_ToolTriangulatedShape::Tessellate (myshape, myDrawer);
+
+        // Set to update wireframe presentation on triangulation.
+        if (myDrawer->IsoOnTriangulation())
+        {
+          SetToUpdate (AIS_WireFrame);
+        }
+      }

@@ -444,17 +444,27 @@ void AIS_TexturedShape::Compute (const Handle(PrsMgr_PresentationManager3d)& /*t
           BRepTools::Clean (myshape);
         }
       }
+      if (!StdPrs_ToolTriangulatedShape::IsTessellated (myshape, myDrawer))
+      {
+        StdPrs_ToolTriangulatedShape::Tessellate (myshape, myDrawer);
+
+        // Set to update wireframe presentation on triangulation.
+        if (myDrawer->IsoOnTriangulation())
+        {
+          SetToUpdate (AIS_WireFrame);
+        }
+      }

+void AIS_InteractiveContext::SetIsoOnTriangulation (const Standard_Boolean theIsEnabled,
+                                                    const Handle(AIS_InteractiveObject)& theObject)
+{
+  if (theObject.IsNull())
+  {
+    myDefaultDrawer->SetIsoOnTriangulation (theIsEnabled);
+    return;
+  }

+++ b/src/StdPrs/StdPrs_Isolines.cxx
+#include <Adaptor3d_IsoCurve.hxx>
+#include <BRepTools.hxx>
+#include <BRep_Tool.hxx>
+#include <ElCLib.hxx>
+#include <ElSLib.hxx>
+#include <GCPnts_AbscissaPoint.hxx>
+#include <GeomLib_Tool.hxx>
+#include <TColgp_Array1OfPnt.hxx>
+#include <TColgp_Array1OfPnt2d.hxx>
+#include <TColStd_Array1OfInteger.hxx>
+#include <TColStd_SequenceOfReal.hxx>
+#include <TColgp_SequenceOfPnt2d.hxx>
+#include <NCollection_List.hxx>
+#include <NCollection_QuickSort.

+  inline Handle(Graphic3d_ArrayOfSegments) PrimitivesForPolyline (const Prs3d_NSequenceOfSequenceOfPnt& thePoints)
+  {
+    if (thePoints.IsEmpty())
+    {
+      return NULL;
+    }

+    Prs3d_NListIteratorOfListOfSequenceOfPnt anIt;
+    for (Prs3d_NSequenceOfSequenceOfPnt::Iterator anIt (thePoints); anIt.More(); anIt.Next())
+    {

+++ b/src/StdPrs/StdPrs_Isolines.cxx
+    Standard_Real aDelta = 1;

+  inline Standard_Boolean Project (const gp_Pln& thePlane,

+      Handle(TColgp_HSequenceOfPnt) anIsoPnts = aUPolylines.ChangeValue (aUIsoIndexes.Value (anIsoIdx));

+    if (Abs (aDistanceUV2) < Precision::PConfusion())
+    {
+     theSegment[aNPoints++] = aNode2;
+      aLinkIter++;

+    // Isoline crosses degenerated link.
+    if (aNode1.Distance (aNode2) < Precision::PConfusion())
+    {

+//! Tool for computing isoline presentation for a triangulated face and or surface.
+class StdPrs_Isolines : public Prs3d_Root

+namespace
+{
+  typedef NCollection_List<Handle(TColgp_HSequenceOfPnt)> ListOfSequenceOfPnt;
+};

+  Standard_Integer aNbVertices = aSurfPoints.Length();
+  Standard_Integer aNbBounds   = (Standard_Integer)aNbVertices / 2;

+  Handle(Graphic3d_ArrayOfPolylines) aSurfArray = new Graphic3d_ArrayOfPolylines (aNbVertices, aNbBounds);
+  for (Standard_Integer anI = 1; anI <= aNbVertices; anI += 2)
+  {
+    aSurfArray->AddBound (2);
+    aSurfArray->AddVertex (aSurfPoints.Value (anI));
+    aSurfArray->AddVertex (aSurfPoints.Value (anI + 1));
+  }

+  else if (aCmdName == "visoontriangulation")
...
+  theCommands.Add ("visoontriangulation",
+                    "visoontriangulation [name] [0|1]"
+                    "\n\t\t: Alias for vaspects -isoontirangulation [name] [0|1].",
+                    __FILE__, VAspects, group);

+      aDrawer->SetIsoOnTriangulation (aChangeSet->ToEnableIsoOnTriangulation);

+vinit

+vviewparams -scale 9787.9970467038638 -proj -0.011455629713785871 -0.99982938298007373 0.014490461605680582
+vviewparams -up -0.015526407227439337 0.014667523215136941 0.99977187119929578 -at 0.050299998372793191 8.8835102362048592e-020 -1.5178830414797062e-018

+# Visualization - Build wireframe representation consistent with the shape's triangulation
+#

-      StdPrs_ShadedShape::Tessellate (myshape, myDrawer);
+      StdPrs_ToolTriangulatedShape::Tessellate (myshape, myDrawer);
+
+      // Set to update wireframe presentation on triangulation.
+      if (myDrawer->IsoOnTriangulation())
+      {
+        SetToUpdate (AIS_WireFrame);
+      }

+---Purpose: Enables or disables on-triangulation build for isolines.

+  //! Returns True if the drawing of isos on triangulation is enabled.
+  Standard_Boolean IsoOnTriangulation() const { return myIsoOnTriangulation; }