COConst-me·Nov 22, 2021
Some parts of the 3MF are actually good. I like the spec documents winding order of the meshes. The format includes units, and these optional 4x4 transformation matrices — both are useful.
As for need of the new formats, for one, modern CAD formats are insanely complex. These IGES/STEP/BREP files require many megabytes of very complicated code to deal with, such as this library https://github.com/tpaviot/oce These formats may even contain proprietary extensions. Also, they need non-trivial processing power to handle. Many people wouldn’t want a Core i7 with gigabytes of RAM in their 3D printers, inflates hardware cost and software complexity.
Besides, we now have high-resolution 3D scanners, and CAE software which algorithmically optimizes models by running numerical simulations. They both output triangle meshes instead of CAD files. Scan
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ners often output point clouds one can convert into triangles, but hard to convert into CAD formats.
I just don’t like the 3MF implementation too much. XML is fine for kilobytes of data, but not many megabytes. If I would be designing that format, I would probably made it binary. Maybe EBML https://en.wikipedia.org/wiki/Extensible_Binary_Meta_Languag... would work for that; it does fine for MKV videos, which is also a huge pile of structured data with non-trivial performance constraints for producers and especially parsers.
Another minor thing, it was not the best idea to make name start with a digit. Most programming languages forbid identifiers like that for their classes / functions / namespaces / modules.