One of my favorite areas in Berlin is the Museum Island. It includes the Egyptian Museum, which is part of the Neues Museum. Among its most famous possessions is a bust of Nefertiti which dates from about 1340 BCE. The museum has an entire room dedicated to Nefertiti.
More relevant to this blog, it has made a detailed 3D scan of the bust. The museum belongs to the Prussian Cultural Heritage Foundation, which is funded by the federal government and the 16 state governments. Supposedly it has an obligation to make its information public, but for reasons that aren’t clear, it held tight to that scan for a long time. It’s now available as a free download, ten years after it was made, thanks to the persistent efforts of Cosmo Wenman. He tells the story on Reason.com.
It must be a surprise to most people, but you can represent three-dimensional objects in PDF, in spite of its strictly 2-dimensional imaging model. It turns out there are two ways to do it, with the older U3D and the more modern PRC. What makes them possible is PDF’s annotation feature, which allows capabilities to be added to PDF, and the Acrobat 3D API. Full support of these features requires implementation of at least PDF 1.7 Extension Level 1, or to put it in application terms, Acrobat 8.1.
The PDF/E standard for engineering documents, aka ISO 24517, includes U3D but not PRC. A PDF/E-2 standard is currently in development and is expected to include PRC. PDF/E, like the other slashes of PDF, is a subset of the PDF standard (version 1.6), so obviously it’s possible to do 3D work without reference to it. It’s intended for cases where long-term retention or archiving is important. This suggests some affinity with PDF/A, which is specifically aimed at archive-quality documents, and the PDF Association, which is heavily involved in PDF/A, has recently started a PDF/E Competence Center. Oddly, the competence center says that PDF/E-1 “does not address 3D,” though other sources say PDF/E does reference U3D. Perhaps this is a matter of what really constitutes “addressing” 3D as opposed to just acknowledging it.
The 3-D printing industry has been moving toward 3MF as a standard file format. It’s an XML-based format that claims to offer extensibility, interoperability, and freedom from the problems of other formats. The specification includes an XSD schema. I’m no judge of how suitable it is for 3D modeling, but yes, it is extensible. In fact, it’s designed with a relatively lean core model, so additional features can be added as extensions.
A recent Fortune article, “Why These Big Companies Want a New 3D File Format”, discusses 3MF from a business standpoint.
The old STL format, based on tessellation, is widely used, but it’s been criticized for generating huge files and lacking features.
Posted in News
Tagged 3D, printing, XML
3D printing is an exciting new technology, but the formats to choose from are an alphabet soup.
A call for “PDF 2.0” or an “Analytical File Format.” The description is vague, but it sounds like something analogous to the Semantic Web for documents.
BW64, a new RIFF-based audio format. The article describes it as a “3D” format, but more significantly it’s a metadata-rich interchange format that supports really big files.
And just for bitter laughs: I need a ‘file’ format.”
Posted in Links
Tagged 3D, audio, PDF