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[Andy Peters <devel@xxxxxxxxx>]

Can someone please definitively explain the purpose of the Grid Origin in pcbnew? This comes up on the user list and Kicad.info forums regularly.

Coordinate (0,0) is always defined as the upper left corner of the sheet on which the PCB is “drawn.” This origin is outside of the normal drawing area. I am looking at a layout I am working on now, and I put the “grid origin” in the upper-left corner of the board edge, which is at (25, 50) (in millimeters). We can move the “Grid Origin” to anywhere on the sheet, but exactly what does it do and why is it needed?

The description in the pcbnew manual is:

“Grid origin. (grid offset). Useful for placement of pads. The grid origin can be put on a given location (the first pad to place), and after the grid size can be set to the pad pitch. Placing pads is therefore very easy.” This would imply that it is wholly irrelevant for layout, and only useful in the footprint editor.

I am glad to update the docs with a more cogent description, but I (and obviously many other users) don’t understand it at all.

Thanks.