# File easy_vtk.rb, line 123
  def set_axes( x, y, z, scale=nil )
    x = get_vtkArray( x )
    y = get_vtkArray( y )
    z = get_vtkArray( z )
    if scale
      unless Array === scale
        raise "scale must be Array"
      end
      if scale.length != 3
        raise "length of scale must be 3"
      end
      @scale = scale
      for i in 0...x.GetNumberOfTuples
        x.SetValue( i, x.GetValue(i)*scale[0] )
      end
      for i in 0...y.GetNumberOfTuples
        y.SetValue( i, y.GetValue(i)*scale[1] )
      end
      for i in 0...z.GetNumberOfTuples
        z.SetValue( i, z.GetValue(i)*scale[2] )
      end
    end
    @grid = Vtk::RectilinearGrid.new
    @grid.SetDimensions( x.GetNumberOfTuples, y.GetNumberOfTuples, z.GetNumberOfTuples )
    @grid.SetXCoordinates( x )
    @grid.SetYCoordinates( y )
    @grid.SetZCoordinates( z )
    return nil
  end