Wow! I can't say i've ever said or thought that about PDF before. but after checking out the demo of Acrobat 3D. i'm blown away!

Embed 3d objects in PDFs that can be animated. zoomed. moved and interacted with through text links in the document...

This is a 2.8MB PDF doc with a neat little animation in it of an engine.

Click on the engine. wait for the menus to open up...then zoom. move around and change lighting. Then to animate it. click on the text links in the paragraph immediately to the left of it.

This is crazy cool. Add Flash and who knows what a PDF document would be capable of. This may very well become the best way EVER to produce a shop manual or any type of user guide for physical objects!