Researching file formats 26: 3DM

This blog post is part of a series on file formats research. See this introduction post for more information.

Update: The official format definition is now online here: 3D Model File Format Family. Comments welcome directly to the Library of Congress.

The next six formats are part of Set 3: 3D, VR and Animation! All of these formats are quite different from each other (except two closely related, which will be obvious).

First up: 3DM. Rhino 3D Model file format family. Or the openNURBS 3D model?

Something important to note off the top is that openNURBS is an initiative, a toolkit, and the name of a file format. There’s some mixing of definitions across descriptions, which can be a little hard to keep track of, but I did my best.

I’m having to learn a lot about NURBS as I work through this set. 3D stuff has always been not my jam; I find it unnerving. This format led me down some paths related to Blender plug-ins, and the websites all creeped me out with their representations of Sim-like bodies in questionable default poses, or featuring oozing shapes that are way too pristine.

Between this and another format, I was really questioning what “open” meant, because according to some companies, it doesn’t seem to mean transparent nor available.

Here’s a post on the web forum asking “I am trying to find a specification or documentation for the 3DM file format. However, I have not been able to find any relevant documents on the official website, the internet, or forums.” The first reply is “If you can to use the toolkit as a black box, as many do I’m sure, then you can do that. If you want to evaluate what we are doing in detail, you can always read the header comments and trace through the code.”

Is that open?

This format feels a bit like abandonware to me, or at least it’s approaching that title soon? This thought series to be continued next week.