Interesting, I've been doing 3D SVG by storing the xyz-coordinates in a separate array and using inlined javascript to calculate & refresh the 2D coordinates of the SVG items themselves after rotation. But this means that the file only works in a browser. Maybe it could be possible to replace the javascript with native functions, so the same file would work everywhere.
How do you transform paths? Do you just transform the control points?
Yeah, paths are saved in an array where each path segment is a list of control points coupled with the corresponding path command (M, L, C). Those can be used to recreate the path item.