fix VTK format for Hexa20, Hexa27 and Tetra10

Geo/MHexahedron.h

@@ -267,6 +267,12 @@ class MHexahedron20 : public MHexahedron {
                                 19, 14, 11, 15, 13, 8, 16, 17, 10};
     return getVertex(map[num]);
   }
+  virtual MVertex *getVertexVTK(int num)
+  {
+	  static const int map[20] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 11, 13,
+		  9, 16, 18, 19, 17, 10, 12, 14, 15 };
+	  return getVertex(map[num]);
+  }
   virtual int getNumEdgeVertices() const { return 12; }
   virtual int getNumEdgesRep(bool curved);
   virtual void getEdgeRep(bool curved, int num, double *x, double *y, double *z, SVector3 *n);
@@ -372,6 +378,12 @@ class MHexahedron27 : public MHexahedron {
                                 23, 21, 1, 9, 11, 19, 16, 4, 12, 14, 22, 10, 13};
     return getVertex(map[num]);
   }
+  virtual MVertex *getVertexVTK(int num)
+  {
+	  static const int map[27] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 11, 13, 9, 16, 18, 19, 17, 10, 12, 14,15, 22, 
+									23, 21, 24, 20, 25, 26};
+	  return getVertex(map[num]);
+  }
   virtual int getNumEdgeVertices() const { return 12; }
   virtual int getNumFaceVertices() const { return 6; }
   virtual int getNumVolumeVertices() const { return 1; }

Geo/MTetrahedron.h

@@ -239,6 +239,11 @@ class MTetrahedron10 : public MTetrahedron {
     static const int map[10] = {0, 1, 2, 3, 4, 5, 6, 7, 9, 8};
     return getVertex(map[num]);
   }
+  virtual MVertex *getVertexVTK(int num)
+  {
+	  static const int map[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 9, 8};
+	  return getVertex(map[num]);
+  }
   virtual MVertex *getVertexDIFF(int num){ return getVertexBDF(num); }
   virtual MVertex *getVertexINP(int num){ return getVertexBDF(num); }
   virtual int getNumEdgeVertices() const { return 6; }