[vtkusers] help needed setting up the colormap/lookup table/mapper in C++

[David, John]

Sometime back I wrote a simple point cloud to VTK converter which had the following output structure:

  # vtk DataFile Version 2.0
  loop
  ASCII
  DATASET UNSTRUCTURED_GRID
  POINTS 1150 float
      758301.12       555277.12            6.70
      758301.50       555183.19            3.50
  ...

  CELLS 1150 2300
  1 0 
  1 1 
  ...

  CELL_TYPES 1150
  1 
  1 
  ...

  POINT_DATA 1150
  SCALARS Z_Value float 1 LOOKUP_TABLE default 
  6.700000 
  3.500000 
  ...

I have been unable to figure out how to fully implement the equivalent on the fly in C++.  The following is some test code which appears to get the point data set up correctly, but I cannot figure out how to set up the colormap/lookup table/mapper:

    vtkPoints *points = vtkPoints::New();
    vtkCellArray *polys = vtkCellArray::New();

    for (i=0; !in.eof() && in.good(); i++)
    {
      in >> x >> y >> z;
      points->InsertPoint(i, x, y, z);
    }

    polys->InsertNextCell(points->GetNumberOfPoints());
    for (i=0; i<points->GetNumberOfPoints(); i++)
    {
        polys->InsertCellPoint(i);
    }

	vtkPolyData *polyData = vtkPolyData::New();
	polyData->SetPoints(points);
	polyData->SetPolys(polys);

    polyData->Update();

        vtkPolyDataWriter* writer1 = vtkPolyDataWriter::New();

        writer1->SetInput(polyData);
        writer1->SetFileName( "test_points.vtk" );
        writer1->Update();

        writer1->Delete();


I have not found any solutions on line, and my book order has not arrived yet (originally ordered through Amazon, and placed on back oder for 6+ months).  Any pointers will be appreciated.

Thanks and best regards,

  EBo --