Answered
I am using Acrobat 9.2.0 with Inventor 2009 and Word 2003. I can insert a 3D model using pdfMaker just fine. It has full 3D functionality in the Word document. When I then convert that Word document to PDF, again with pdfMaker, the 3D just comes through as an image with no 3D functionality in the PDF file. I have been able to do this in the past with Acrobat 8 3D and Inventor 10. I have spent a full day trying to correct this to no avail. Any thoughts would be greatly appreciated.
In Word, open PDFMaker's settings (menu - Adobe PDF - change conversion settings) and make sure in the settings tab:
1) enable accessibility and reflow (tags) is ticked
2) Distiller preset - click 'advanced' and make sure the PDF version is Acrobat 8 (PDF1.7)
When exporting the PDF using the toolbar button in Word, press "options" and make sure reflow/tags is checked in there too. It will remember your choice but doesn't always follow what the settings panel says.
Personally I prefer to load 3D content directly with Acrobat, leaving an empty space in the source document and drawing it on after conversion. There are more options available for optimizing the import and setting up the annotation.