I have uncompressed a PDF and I am able to view the streams and know where the data for the 3d model is kept. I have also extracted the section that describes the PRC part of the file. I have used SumatraPDF in order to view the file as it supports PRC. But it shows an error. How can extract the 3D model from the PDF?
That I will be able to extract the 3D model from the PDF in any format so I can ultimately convert it into a format which can be viewed and edited if need be.
Currently SumatraPDF does not RUN 3D models nor other embeds nor attachments (one of the reasons its considered SAFEST PDF reader). It will accept as .PDF, Adobe ONLY supported 3D PRC / U3D, or other PRCs (Palm Reader Compressed eBook) which are runnable as plain text.
It can show any static 3D cover image (and as work in progress in some versions allow extract some types of attachment) or potentially delete attached annotations (not what you want). https://github.com/GitHubRulesOK/MyNotes/raw/master/Acrobat%203D%20test%20-%20Laughing%20Porpoise.pdf
It is possible in PDF editors to run, view and extract such contents, possibly via their API/SDK.