A zone outline is where copper may go, not where it ends up: on the rc4
sense board the board-wide GND pours break into islands around other
nets' tracks, and treating every pad inside them as connected left 28
GND islands unjoined (63 unconnected against 42 without zones). Trust a
zone only when a no-tracks rule area covers it on its layer, as the
power stage's pours are covered; route the rest with tracks as before.
rc4, exact engine, resolution 2: power stage 5 unconnected (JAR 12),
sense board 41 (JAR 32), no DRC errors on either.
freeroute ignored the DSN's planes (KiCad's zones), so it never knew that
pads in a pour are joined by it. On the rc4 power stage those pads sit
inside "keep router off" areas as well, and every connection to them was
dropped without a word.
- Read (plane <net> <shape>) and put each zone on the board as a
ConductionArea of its net. Zones are not obstacles: KiCad refills them
around other nets' copper.
- The grid groups each net's pads and zone pieces that copper already
joins (a pad in a zone, two zones sharing a pad) and routes only between
groups. A connection may end on a zone by a via inside its copper, or by
a track where tracks are allowed.
- wire_keepout now blocks traces only, as KiCad's "no tracks" rule area
does; via_keepout only vias; keepout both, in the grid and in the exact
verifier.
rc4 power stage, exact engine, resolution 2: 2 unconnected, down from 8
(FreeRouting JAR: 12), no DRC errors.
The grid search estimated the remaining distance as a straight line even
when only orthogonal steps exist; Manhattan is the tighter estimate those
moves admit and still never overestimates. --heuristic-weight W (default
1) makes it weighted A*: routes at most W times the shortest (tested).
A cell was exactly one trace plus its clearance, so a trace owning its cell
was the whole clearance model, and the 0.4 mm grid could not reach most
pins of a 0.5 mm pitch package: between two 0.3 mm pads a trace's centre
has a legal band only 0.15 mm wide. Resolution K makes cells K times
finer and has every trace claim a halo, the cells whose centre is nearer
than trace + clearance to one of its own, released again on rip-up.
K = 1 has an empty halo and is the old grid exactly (tested). On a 0.5 mm
row, K = 4 gets every pin out where K = 1 gets two. On the rc4 boards, K = 2
cuts the sense board's opens from 66 to 41 (JAR: 32) and the power board's
to 7 (JAR: 12), still with no DRC errors from freeroute's own copper.
Every route starts and ends with a stub from the pin to its first grid
cell, and the grid never saw that copper: on the rc4 sense board 24 of 39
connections the exact verifier rejected had a later route pass beside an
earlier stub. A route's stubs now claim the cells they come near, a stub
must be clear of other nets to be used, and a route may start from any
enterable neighbour of the pin cell, costed by stub length (Manhattan on
the orthogonal track, so a pin on a cell centre still leaves straight).
Tests: a route near a rounded corner keeps its edge clearance; and a
strict xfail that pins down the remaining gap, a 0.5 mm pin row the grid
cannot give a column to every pin of.
rsp2k