[vtkusers] Using vtkFieldData

[John Norris]

Hi,

I've using a vtkHierarchicalDataSet to represent my multi-block data. 
I'd like to preserve certain block-specific information (e.g. the 
block's text label), but haven't figured out a good way to do this yet. 
  I tried adding a vtkCharArray to the vtkFieldData of each of the 
component datasets, but this doesn't appear to be passed down the pipe. 
  I've tried a simple example using a regular vtkStructuredPoints, and 
it doesn't seem to pass along its vtkFieldData either.  A code snippet 
follows.

Is there any way, other than converting the string to cell or point 
data, to get this data passed through filters?

Thanks,
John

   vtkStructuredGrid* pStrGrid = vtkStructuredGrid::New();
   <set the grid's points and point data>

   // Create the array to add to the field data.
   char* charData = new char[16];
   strcpy(charData, "Hello!");
   vtkCharArray* pText = vtkCharArray::New();
   pText->SetArray(charData, strlen(charData) + 1, 0);
   pText->SetName("Text Test");

   // Add to the field data.
   pStrGrid->GetFieldData()->AddArray(pText);
   pText->Delete();
   pStrGrid->GetFieldData()->CopyAllOn();

   // Pass the data through a filter.
   vtkContourFilter* pContour = vtkContourFilter::New();
   pContour->UseScalarTreeOn();
   pContour->GenerateValues(5, 0.1, 1.0);
   pContour->SetInput(pStrGrid);

   // Force an update.
   pContour->GetOutput()->Update();

   // Print info on the original grid.
   // Its Field Data will contain one array named 'Text Test'.
   std::cout << "Original Grid:\n";
   pStrGrid->Print(std::cout);

   // Print info on the contours.
   // Its Field Data will not contain any arrays.
   std::cout << "\nContours:\n";
   pContour->GetOutput()->Print(std::cout);

-- 
John Norris
Research Programmer
Center for Simulation of Advanced Rockets
http://www.uiuc.edu/ph/www/jnorris