PDFs can contain embedded U3D objects.
See this one for example - http://www.carare.eu/eng/content/download/2601/20492/version/1/file/Castle_of_Bouvignes_Belgium_landscape.pdf
Is there a way to extract the .U3D object from a PDF so that it can be viewed and edited in another program?
I've tried opening the PDF in Acroread - it renders the 3D object, but there's no way to export it.

PDFedit doesn't seem to have any support.
Would be very handy if it were Linux command line - but that's not essential.