I exported my project as an IDF lib, and I found that the pcb board itself is shortened by
0.1mm in width and height.
I’ve come to this result comparing the IDF lib file produced against the kicad_pcb
(general->area section).
Is there a reason for this?
I’m not totally sure what the general->area section is about, but is seems it is the pcb board rectangular area?
Did I misunderstood it?
Did you draw a board outline or are you relying on KiCad magically creating a rectangular board?
If you drew a board outline then the dimensions are correct. I don’t know what that general area section is really about.
The IDF description itself is accurate to 0.1 microns. I suspect you doesn’t really know what you doing and are imagining problems where there are none.
I have heard that if you ask KiCad to calculate the max/min extent of the board, the extent will include the line width. That’s just the way KiCad does it. This only matters for things which are not important, which is why no one cares to make it correct. The IDF code does things differently so it’s always correct.
The VRML export code should also be correct; the 3D viewer may not be correct if there is no explicit board edge, because KiCad caluclates one itself.