[vtkusers] Opacity not correct when using vtkColorTransferFunction

[Chiang, Wen-Hsing]

Hi there,

When I use vtkColorTransferFunction to map the color to an isosurface
with opacity=0.2 for the actor, the isosurface seems to be opaque (it is
a little transparent though, something like opacity>0.9...). This
problem does not exist when I use vtkLookupTable instead of
vtkColorTransferFunction. However, the later is preferred as it gives me
more control. 

Is anyone aware of this problem? Any responses are appreciated. I am
using vtk4.0.

Wen-Hsing Chiang