D114 — Read-only reference-return audit

Decision

The reference-return audit (issue #7) is a read-only geometric pass: copper under each selected trace on its reference layer, and where there is none the return is the shortest path on the remaining reference copper (A* over the visibility graph of the region's vertices), reported as a detour and a separation; a layer change closes through the nearest stitching via of the reference net or the nearest capacitor between the two reference nets, within a radius; a pad's return pad is the nearest pad of the reference net. Selected by net name, class or pair, off by default; thresholds are warnings; after a route the zones are refilled for the new copper

Alternatives

A field solver; one assumed ground ball per pin; judging the fills stored in the file after routing (they have no antipads for the new vias); adding the audit to the DRC errors (KiCad has no such rule, and a geometric estimate is not a violation)

Reason

The issue asks per net for continuous copper and the detour, not for a current-density map. The nearest-pad return and the nearest stitch or capacitor follow the comment on the issue. A geometric estimate with stated limits is useful and honest; presenting it as a violation would not be (doc 05 §42)