Volume visualization strangeness

[John Osborne <oz@xxxxxxxxxxxxx>]

I have been sucessful in creating a volume rendering with alpha 
transparency. However, I find when roating the volume (either manually 
or programatically) that there are certain orientations of the cube when 
the volume rendering disappears and all you see are some color splotches 
on the faces of the cube. What's going on?

John Osborne
NOAA/PMEL