VTK/Examples/MiscPointData

#include <vtkCellData.h>
#include <vtkDoubleArray.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPointData.h>
#include <vtkSmartPointer.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkPolyDataNormals.h>
 
int main(int argc, char *argv[])
{
  //get filename from command line
  vtkstd::string filename = argv[1]; //first command line argument
 
  //Read the file
  vtkSmartPointer<vtkXMLPolyDataReader> reader = 
    vtkSmartPointer<vtkXMLPolyDataReader>::New();
  cout << "Reading " << filename << endl;
  reader->SetFileName(filename.c_str());
  reader->Update();
 
  //extract the polydata
  vtkSmartPointer<vtkPolyData> polydata = reader->GetOutput();
 
  //get the number of points in the polydata
  vtkIdType idNumPointsInFile = polydata->GetNumberOfPoints();
 
  //add distances to each point
  vtkSmartPointer<vtkFloatArray> distances = vtkSmartPointer<vtkFloatArray>::New();
  distances->SetNumberOfComponents(1);
  distances->SetName("Distances");
 
  for(unsigned int i = 0; i < idNumPointsInFile; i++)
    {	
    distances->InsertNextValue(vtkMath::Random(0.0,1.0););
    }
 
    polydata->GetPointData()->AddArray(distances);
 
  return 0;
}