[vtkusers] vtkDataSetMapper and lookuptable ?

[Maurice van de Rijzen]

Dear all,
I 've a problem.
I'm using tetraeders to generate a velocity model of the earth.
Using

vtkUnstructuredGridReader reader
    reader SetFileName "model.vtk"
    reader SetLookupTableName "my_table"
    reader SetScalarsName "my_scalar"
    reader SetVectorsName "my_vector"

vtkShrinkFilter shrink
    shrink SetInput [reader GetOutput]
    shrink SetShrinkFactor 0.9

vtkDataSetMapper map
  map SetInput [shrink GetOutput]

I know for this example that the scalars are in between 0.2 and 0.3.
I can visualize the dataset on screen and I can disrimate the difderence 
between 0.2 and 0.3.
However, when I add the following command:

 map SetScalarRange 0.2 0.3

I can no longer discrimate the different points and all the point have 
the same color.
In both cases I've not created an instance of vtkLookupTable, I assumed 
the mapper would take care of it.
I'm obviously forgetting something but I don't know what.

Maurice