have you adjusted any of the setting in the preference panel as shown in the screen shot above.
And you have to remember that only certain Graphics cards are capable of 3D.
Thank you for your reply, Phillip.
Yes, we have looked at the settings in this panel. As mentioned above, we have changed the settings in Preferred Renderer to Software (from OpenGL)which causes transparency to work, but without shadows.
Using the same computer but running Acrobat 8 Pro works with OpenGL, and using other machines in the office (various forms of Macbook Pros, MacPros, iMacs, etc) also show the same issue - the lack of OpenGL render quality in Acrobat X vs Acrobat 8.
Doesn't seem to be a hardware issue, but am open to ideas.
I am not sure at all, but the only thing I have seen to have similar effects is the use of per-vertex colors.
BTW, a better place to ask such questions is Acrobat 3D Features forum.
Adobe people may ignore you there, but in some cases they accepted bug reports via that forum and fixed reported bugs.