Index: vtkTriQuadraticHexahedron.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/Filtering/vtkTriQuadraticHexahedron.cxx,v
retrieving revision 1.8
diff -u -r1.8 vtkTriQuadraticHexahedron.cxx
--- vtkTriQuadraticHexahedron.cxx	31 Jul 2006 22:18:17 -0000	1.8
+++ vtkTriQuadraticHexahedron.cxx	10 Aug 2007 14:19:18 -0000
@@ -46,7 +46,8 @@
   this->Hex = vtkHexahedron::New ();
 
   this->Scalars = vtkDoubleArray::New ();
-  this->Scalars->SetNumberOfTuples (8);
+  this->Scalars->SetNumberOfTuples (8); // vertices of a linear hexahedron
+
 }
 
 //----------------------------------------------------------------------------
@@ -138,10 +139,23 @@
   int i, j;
   double d, pt[3];
   double derivs[81];
+  double hexweights[8];
 
   //  set initial position for Newton's method
-  subId = 0;
   pcoords[0] = pcoords[1] = pcoords[2] = params[0] = params[1] = params[2] = 0.5;
+  subId = 0;
+
+  // Use a tri-linear hexahederon to get good starting values
+  vtkHexahedron *hex = vtkHexahedron::New();
+  for(i = 0; i < 8; i++)
+  	hex->GetPoints()->SetPoint(i, this->Points->GetPoint(i));
+
+  hex->EvaluatePosition(x, closestPoint, subId, pcoords, dist2, hexweights);
+  hex->Delete();
+
+  params[0]  = pcoords[0];
+  params[1]  = pcoords[1];
+  params[2]  = pcoords[2];
 
   //  enter iteration loop
   for (iteration = converged = 0; !converged && (iteration < VTK_HEX_MAX_ITERATION); iteration++)
@@ -176,6 +190,7 @@
     d = vtkMath::Determinant3x3 (rcol, scol, tcol);
     if (fabs (d) < 1.e-20)
       {
+      vtkErrorMacro (<<"Determinant incorrect, iteration " << iteration);
       return -1;
       }
 
@@ -195,6 +210,7 @@
     else if ((fabs (pcoords[0]) > VTK_DIVERGED) ||
       (fabs (pcoords[1]) > VTK_DIVERGED) || (fabs (pcoords[2]) > VTK_DIVERGED))
       {
+      vtkErrorMacro (<<"Newton did not converged, iteration " << iteration << " det " << d);
       return -1;
       }
 
@@ -207,10 +223,12 @@
       }
     }
 
+
   //  if not converged, set the parametric coordinates to arbitrary values
   //  outside of element
   if (!converged)
     {
+      vtkErrorMacro (<<"Newton did not converged, iteration " << iteration << " det " << d);
     return -1;
     }
 
@@ -299,7 +317,7 @@
     for (int j = 0; j < 8; j++)
       {
       this->Hex->Points->SetPoint (j, this->Points->GetPoint (LinearHexs[i][j]));
-      this->Hex->PointIds->SetId (j, LinearHexs[i][j]);
+      this->Hex->PointIds->SetId (j, this->PointIds->GetId(LinearHexs[i][j]));
       this->Scalars->SetValue (j, cellScalars->GetTuple1 (LinearHexs[i][j]));
       }
     this->Hex->Contour (value, this->Scalars, locator, verts, lines, polys,
@@ -325,7 +343,7 @@
     for (int j = 0; j < 8; j++)
       {
       this->Hex->Points->SetPoint (j, this->Points->GetPoint (LinearHexs[i][j]));
-      this->Hex->PointIds->SetId (j, LinearHexs[i][j]);
+      this->Hex->PointIds->SetId (j, this->PointIds->GetId(LinearHexs[i][j]));
       this->Scalars->SetValue (j, cellScalars->GetTuple1 (LinearHexs[i][j]));
       }
     this->Hex->Clip (value, this->Scalars, locator, tets, inPd, outPd, inCd, cellId, outCd, insideOut);
@@ -613,10 +631,10 @@
   derivs[17]= g3r_r * g1s * g2t;
   derivs[18]= g3r_r * g3s * g2t;
   derivs[19]= g1r_r * g3s * g2t;
-  derivs[20]= g2r_r * g1s * g2t;
+  derivs[20]= g1r_r * g2s * g2t;
   derivs[21]= g3r_r * g2s * g2t;
-  derivs[22]= g2r_r * g3s * g2t;
-  derivs[23]= g1r_r * g2s * g2t;
+  derivs[22]= g2r_r * g1s * g2t;
+  derivs[23]= g2r_r * g3s * g2t;
   derivs[24]= g2r_r * g2s * g1t;
   derivs[25]= g2r_r * g2s * g3t;
   derivs[26]= g2r_r * g2s * g2t;
@@ -642,10 +660,10 @@
   derivs[44] = g3r * g1s_s * g2t;
   derivs[45] = g3r * g3s_s * g2t;
   derivs[46] = g1r * g3s_s * g2t;
-  derivs[47] = g2r * g1s_s * g2t;
+  derivs[47] = g1r * g2s_s * g2t;
   derivs[48] = g3r * g2s_s * g2t;
-  derivs[49] = g2r * g3s_s * g2t;
-  derivs[50] = g1r * g2s_s * g2t;
+  derivs[49] = g2r * g1s_s * g2t;
+  derivs[50] = g2r * g3s_s * g2t;
   derivs[51] = g2r * g2s_s * g1t;
   derivs[52] = g2r * g2s_s * g3t;
   derivs[53] = g2r * g2s_s * g2t;
@@ -671,13 +689,18 @@
   derivs[71] = g3r * g1s * g2t_t;
   derivs[72] = g3r * g3s * g2t_t;
   derivs[73] = g1r * g3s * g2t_t;
-  derivs[74] = g2r * g1s * g2t_t;
+  derivs[74] = g1r * g2s * g2t_t;
   derivs[75] = g3r * g2s * g2t_t;
-  derivs[76] = g2r * g3s * g2t_t;
-  derivs[77] = g1r * g2s * g2t_t;
+  derivs[76] = g2r * g1s * g2t_t;
+  derivs[77] = g2r * g3s * g2t_t;
   derivs[78] = g2r * g2s * g1t_t;
   derivs[79] = g2r * g2s * g3t_t;
   derivs[80] = g2r * g2s * g2t_t;
+
+  // we compute derivatives in in [-1; 1] but we need them in [ 0; 1]  
+  for(int i = 0; i < 81; i++)
+  	derivs[i] *= 2;
+
 }
 
 //----------------------------------------------------------------------------
Index: vtkTriQuadraticHexahedron.h
===================================================================
RCS file: /cvsroot/VTK/VTK/Filtering/vtkTriQuadraticHexahedron.h,v
retrieving revision 1.8
diff -u -r1.8 vtkTriQuadraticHexahedron.h
--- vtkTriQuadraticHexahedron.h	27 Feb 2007 23:34:50 -0000	1.8
+++ vtkTriQuadraticHexahedron.h	10 Aug 2007 14:19:19 -0000
@@ -30,6 +30,32 @@
 // (3,0,4,7;11,16,15,19), (0,1,2,3;8,9,10,11), (4,5,6,7;12,13,14,15).
 // The last point lies in the center of the cell (0,1,2,3,4,5,6,7).
 //
+// \verbatim
+//
+// top 
+//  7--14--6
+//  |      |
+// 15  25  13
+//  |      |
+//  4--12--5
+//
+//  middle
+// 19--23--18
+//  |      |
+// 20  26  21
+//  |      |
+// 16--22--17
+//
+// bottom
+//  3--10--2
+//  |      |
+// 11  24  9 
+//  |      |
+//  0-- 8--1
+//  
+// \endverbatim
+//
+
 // .SECTION See Also
 // vtkQuadraticEdge vtkQuadraticTriangle vtkQuadraticTetra
 // vtkQuadraticQuad vtkQuadraticPyramid vtkQuadraticWedge
@@ -99,7 +125,7 @@
   static void InterpolationFunctions (double pcoords[3], double weights[27]);
   // Description:
   // @deprecated Replaced by vtkTriQuadraticHexahedron::InterpolateDerivs as of VTK 5.2
-  static void InterpolationDerivs (double pcoords[3], double derivs[71]);
+  static void InterpolationDerivs (double pcoords[3], double derivs[81]);
   // Description:
   // Compute the interpolation functions/derivatives
   // (aka shape functions/derivatives)
@@ -107,7 +133,7 @@
     {
     vtkTriQuadraticHexahedron::InterpolationFunctions(pcoords,weights);
     }
-  virtual void InterpolateDerivs (double pcoords[3], double derivs[71])
+  virtual void InterpolateDerivs (double pcoords[3], double derivs[81])
     {
     vtkTriQuadraticHexahedron::InterpolationDerivs(pcoords,derivs);
     }
@@ -121,7 +147,7 @@
   // Given parametric coordinates compute inverse Jacobian transformation
   // matrix. Returns 9 elements of 3x3 inverse Jacobian plus interpolation
   // function derivatives.
-  void JacobianInverse (double pcoords[3], double **inverse, double derivs[71]);
+  void JacobianInverse (double pcoords[3], double **inverse, double derivs[81]);
 
 protected:
   vtkTriQuadraticHexahedron ();