[vtkusers] questions for overlay two volumes

[Quan Xue]

Hi, VTKUsers:
      I am writing a program by vtk to put two 3D volumes (original 
volume and segmented volume) together and see the results by controling 
opacity. I have tried vtkImageBlend and vtkAssembly but both of them can 
not work yet. To me, I think vtkImageBlend is a way but I am not sure.
      How to render two volumes at the same time?   Would you give me 
some advices about this question? Are there other classes or examples in 
VTK?
Quan