[vtkusers] Doubts about ray casting class...

[Isabels Siqueira]

Hi,

I am using the class(*) related with ray casting algoritm and I have 
some doubts:
- Which the shading model that the method ShadeOn(), of the class 
volumeProperty, does it use?
- In the same class volumeProperty (SetGradientOpacity), which is the 
method used for the calculation of the gradient?

Thanks,
Isabel

(*)
"vtkPiecewiseFunction"
"vtkVolumeProperty"
"vtkVolumeRayCastCompositeFunction"
"vtkVolumeRayCastMapper"