board.zone

What it is ¶

board.zone(net, layer) yields one row for each layer on which the designer drew a zone for a net. A zone is a region meant to be filled with the net’s copper: a KiCad zone, an Allegro shape boundary, an Altium polygon pour’s outline. It states intent. The copper a fill made is in board.copper with kind pour, where the file stores it.

For hardware engineers ¶

A zone’s outline overlaps other nets’ tracks on purpose, because the fill clears around them, so a zone tells you what was planned rather than what was etched. Use it to ask which planes a design meant to have, or to compare the plan against the copper. On a KiCad board, which keeps no fill, it is the only view of the planes.

For software engineers ¶

Each BoardZone from Model.BoardZones() contributes its (net, layer) pair, deduplicated, so a net with three zones on one layer yields one row. A zone on several layers was split into one zone per layer by the reader. A zone on no net, such as a keepout, yields a row with an empty net.

Go projector ¶

boardFacts in stdlib/relations/facts.go walks Model.BoardZones() after the nets and emits one board.zone(net, layer) row per distinct pair, citing the zone.

The board tier is EMPTY on a netlist-only design, so the relation yields nothing there.

Datalog ¶

Every zone the designer drew, by net and layer:

board.zone(?n, ?layer) => ?n, ?layer

Zones whose net has no poured copper on that layer, which on a board that stores its fills is a zone that was never filled:

board.zone(?n, ?layer), not board.copper(?n, ?layer, "pour") => ?n, ?layer