[vtkusers] Inverse of vtkBoxWidget

[Jose Luis Pina]

Hello:
I´m trying to estract a subvolume from a volume and see the rest, i.e take 
out a bite from a volume.
I tried vtkBoxWidget with InsideOutOff but nothing draws.
The cropping is very near to the desired effect I´m looking for, but I 
don´t want to see the clipping lines along the volume caused by the 
clipping planes.
What I want to do is similar to VolumeRenderWithBoxWidget.tcl but seeing 
the outer volume, not the inside of the cube.
Anyone knows a solution?
Thanks in advance.

Jose Luis Pina Martinez
jlpina at ivo.cps.unizar.es