code: def mapCellsToPoints(self):
          
          c2p = vtk.vtkCellDataToPointData()
          c2p.SetInputData(self.polydata(False))
          c2p.Update()
          return self.updateMesh(c2p.GetOutput())
docs: Transform cell data (i.e., data specified per cell)
          into point data (i.e., data specified at cell points).
          The method of transformation is based on averaging the data values
          of all cells using a particular point.