[vtkusers] vtkColorTransferFunction

[vtk at le.isac.cnr.it]

Hi,
I 'have a problem with tkColorTransferFunction.
I want to visualize one as an example volumetric image (heart.vtk), associating the following colors: 
0 -> Red
64 -> Jellow
128 -> green
255 - > blue
and to the intermediate values the intermediate tonalities of color. 

I have used this code:  

  colorTransferFunction AddRGBPoint    0 1 0 0
  colorTransferFunction AddRGBPoint    64 0 1 0
  colorTransferFunction AddRGBPoint   128 0 1 1
  colorTransferFunction AddRGBPoint    255 0 0 1


but therefore I visualize alone the blue color and the green. 

How I can visualize all the colors demands? 

Thanks