Ryan Malloy
992bba82a0
Extends the grid router with a layer axis: A* nodes are (col, row, layer), in-plane moves stay on a layer, and a via move transitions between layers at a cell for a configurable via_cost (so the router prefers one layer but changes layers to get through). Occupancy is tracked per (cell, layer); a through via must be clear on every signal layer and then blocks all of them for other nets. RouteResult now carries per-layer wire segments and per-net via locations. The pipeline emits each segment on its layer and each via as (via <padstack> x y), using the DSN's via padstack; wire and via coordinates are converted from board units back to DSN units. route() and route_dsn_board() take an optional layers= to restrict routing (e.g. a single layer) for comparison.
freeroute
A native Python PCB autorouter — a Java-free port of the FreeRouting engine.
Why
kicad-mcp currently autoroutes by shelling out to freerouting.jar, which
drags in a JVM dependency. freeroute reimplements the routing engine in
pure Python so the toolchain needs no Java at all.
The contract
The entire integration surface is two Specctra files:
board.dsn ──▶ freeroute ──▶ board.ses
(unrouted) (routed session: traces + vias)
kicad-cli already exports .dsn and imports .ses, so freeroute is a
drop-in replacement for the JAR step — nothing else in the pipeline changes.
Status
Pre-alpha. Under active development. See docs/PORTING_PLAN.md
for the architecture and porting roadmap.
Usage (target)
freeroute board.dsn -o board.ses
Development
uv sync
uv run pytest
uv run ruff check src/ tests/
License
GPL-3.0-or-later, matching the FreeRouting source it is ported from.