Ryan Malloy
89c0481ccc
Implements a working autorouter and the Java-free replacement for the freerouting.jar step: dsn_text -> parse_dsn -> build_board -> route -> write_ses. GridRouter is a single-layer A* maze search over a uniform occupancy grid: a cell is blocked by another net's pad (inflated by clearance + half trace width) or a keepout; each net's ratsnest is connected pin to pin; a routed trace then blocks other nets. The cell path becomes a trace polyline whose endpoints are the exact pin locations. Board-unit paths are converted back to DSN units for the SES (wire (path ...)) scopes. This is an MVP, not a port of FreeRouting's expansion-room maze: free-space rooms, rip-up-and-retry, multi-layer via search, and shove are deferred (they raise quality/coverage, not the connectivity milestone). It reaches connectivity on boards whose nets route on one layer without crossing. Adds tests/dsn/fixtures/simple_2net.dsn (a guaranteed-routable 2-net board). Invariant tests: both nets route, the emitted SES parses, every trace stays on a valid layer and within the board outline, and every routed net's trace endpoints sit exactly on its two pads. An oracle-gated test asserts connectivity parity with the reference FreeRouting JAR on the simple board.
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.