    vol = vtkStructuredPoints()
    vol.SetDimensions(26, 26, 26)
    vol.SetOrigin(-0.5, -0.5, -0.5)
    sp = 1.0 / 25.0
    vol.SetSpacing(sp, sp, sp)

--
    volume = vtkStructuredPoints()
    volume.GetPointData().SetScalars(scalars)
    volume.SetDimensions(resolution, resolution, resolution)
    volume.SetOrigin(xmin, ymin, zmin)
    volume.SetSpacing((xmax - xmin) / resolution, (ymax - ymin) / resolution, (zmax - zmin) / resolution)

