Just an update and a further thank you.
After some further playing and investigation I've managed to figure out both how to get metasequoia files into blender and how to chop meshes in Blender
a la Pepakura Designer. I'm still working on the best way to use the unfolded SVG files to make scaling easy (Inkscape works, but the scaling's a little convoluted).
For the sake of anyone browsing this thread who's interested:
You need to use Blender's add-ons system to get the necessary functionality. Blender's
add-ons manual page explains most of it, but the individual add-ons may have custom requirements, so their manual pages are frequently be a better resource for specific installation instructions.
To get metasequoia files into Blender, you need the 'pymeshio' blender add-on from the Python Packaging Index (PyPI). The
pymeshio page contains the necessary blender install instructions. This add-on supports both metasequoia 'mqo' files and various 'MikuMikuDance' formats (?!?).
To chop meshes in blender in the style of Pepakura Designer, you need the
'Paper Model' Blender Add-on. To fully customize the output of this add-on, you need to understand how UV texture-mapping 'seams' work, as the Paper Model code uses blender's UV code to specify the seam edges (no point in writing the same functionality twice ...). Seams are explained in the
texture-mapping portion of the blender manual.
The output of the 'Paper Model' Add-on is an SVG (scalable vector graphic) file. This can be turned into a PDF by software like Inkscape, but 'convenient' scaling is non-existent (you kind-of have to do the maths by hand). I'm still working on this and will report back once I've figured out the best (i.e. easiest) methods.
Anyway, many thanks to SpaceCowboy again for supplying the Metasequoia files. This isn't just a moot / academic point for me as I have a giant noggin, so even borrowing a windows machine and using pepakura designer to rescale didn't solve the problem as some of the rescaled pieces were too big for A4, thus the mesh needs reslicing for my abnormal skull.
