I'm creating some PDF files that have three-dimensional images (U3D) in them. When I bring them up in Acrobat, everything is fine until I try to print the file. If I've viewed a page, it prints fine, showing the U3D image as I last saw it. If I haven't viewed a page yet, the printout is blank. (I can demonstrate this right from the Print dialog, by previewing pages.)
The only reference I've seen to printing U3D is in the PDF Standard, which says, basically, that this should work. It recommends "PV" or "PO" for the A key in the 3D activation dictionary, and I'm using libharu to build the PDFs. In that dictionary, libharu uses "PV", and when I changed that to "PO" and recompiled nothing changed with the print problem.