I attempted to write some little programs that could support my work in KiCad by manipulating the .kicad_pcb files. When I went through the documentation file_formats.pdf and compared with my files I got the impression that there are quite some differences. I probably could deal with this as far as I can see, but I could not find out how the position and rotation values are stored in the .kicad_pcb files. Still I could identify the movements of value and reference.
Does somebody have some more information that he could share with me.
If you look in a pcbfile for instances of a “module” you will see something like this:
(at 53.5 50.5 90)
That places it at (X,Y) = 53.5, 50.5 mm and rotation +90 degrees. The coordinate system is a screen coordinate with (0,0) in the top left. The units is always mm regardless of your grid unit settings.
For a module with no rotation you’ll get:
(at 53.5 50.5)
For the associated 3D models, the position and rotation parameters are specified differently.
@Andy_P knows most about this afaik.
They have to do with KiCADs abilty to keep track of Schematic/Layout links and the symbols/footprints involved… ie. if you change one in your lib, does it need to update, or not?.. you change the REF value in eeschema, what happens with the footprint in our layout?.. things like that.