[vtkusers] Question using vtkHedgeHog

[Vidya Raghavan]

Dear VTK Users,

I am having trouble displaying surface normals on a 3D model. Basically, 
when I use vtkHedgeHog in my code, I see only the 3D model being displayed 
but not the normals. The code snippet below shows where I'm calling 
vtkHedgeHog and adding the actor to the renderer. Am I doing something 
wrong? I realized in the HedgeHog example from the textbook, the code 
example uses the reader vtkStructuredPointsReader, but I get an error using 
that and I need to use vtkXMLPolyDataReader to read my model data.

Please help!

Thanks,
-vidya
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foreach tissue {1} {

    # write the models to file
     selectTissue ThresholdBetween $tissue $tissue
     writer SetFileName model$tissue.vtk
     writer Write

     #create readers, mappers, and actors
     vtkXMLPolyDataReader reader$tissue
        reader$tissue SetFileName model$tissue.vtk

	vtkHedgeHog hhog
	    hhog SetInput [reader$tissue GetOutput]
	    hhog SetScaleFactor 0.3
	vtkLookupTable lut
	    lut Build
	vtkPolyDataMapper hhogMapper
	    hhogMapper SetInput [hhog GetOutput]
	    hhogMapper SetScalarRange 50 550
	    hhogMapper SetLookupTable lut
	    hhogMapper ImmediateModeRenderingOn
	vtkActor hhogActor
	    hhogActor SetMapper hhogMapper



     vtkPolyDataMapper mapper$tissue
        mapper$tissue SetInput [reader$tissue GetOutput]

    vtkProperty prop$tissue
       prop$tissue SetDiffuseColor [math Random] [math Random] [math Random]
	 prop$tissue SetSpecularPower 50
       prop$tissue SetSpecular .5
       prop$tissue SetDiffuse .8

     vtkActor actor$tissue
        actor$tissue SetMapper mapper$tissue
        actor$tissue SetProperty prop$tissue

        ren AddActor actor$tissue
	  ren AddActor hhogActor
}

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