[vtkusers] Example Medical3 doesnt run

[Pedro Patron]

Hello,

I'm doing an application for medical image.
I need to show the three principal planes (axial, coronal, saggital) from a 
vtkVolume16Reader.
I've executed the example Medical3.cxx and It renders only the translucent 
skin but not the planes.
I don't know what's the problem.
I'm using the 4.2.1 version of VTK over Linux Mandrake 9.0.

Thank you in advance for your help.