On a four-layer board with a GND plane on an inner power layer, freeroute
ignored the plane (it only used zones on routing layers) and chained every
GND pad to the next with tracks across the board. Now a through-hole pad
inside a plane is joined to it already, and for a net with a plane every
other group connects straight to the plane: a route may end on any cell
inside it where a via fits (checked lazily, like other vias), and ending
there places that via. Signal nets are unaffected.
Tested on a four-layer DSN: three SMD GND pads each get a short stub and
their own via, the THT GND pad needs nothing, and no track crosses the
board. Ahead of the TerraHawk ESC, a four-layer board.
rsp2k
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