Ryan Malloy
6a24ffc540
A third engine (engine='room') that replaces the fixed routing grid with FreeRouting's free-space rooms. Per layer, the space not occupied by items (inflated by the routing clearance) is decomposed into exact rectangles via coordinate compression (the orthogonal analogue of CompleteFreeSpaceExpansionRoom); adjacent rooms share an edge door, and a via door joins overlapping rooms on two layers. The maze search is an A* over rooms-through-doors (cost = geometric distance + via cost), so a path may cross a door anywhere along its width rather than at a quantized cell. The found room sequence is realized into an exact orthogonal Polyline through the door mid-gates and verified DRC-clean against the ShapeSearchTree, dropping the net if it cannot be made exactly clean. Maps to autoroute/: ExpansionRoom / CompleteFreeSpaceExpansionRoom (rooms), ExpansionDoor / TargetItemExpansionDoor (doors), MazeSearchAlgo / AutorouteEngine (search), LocateFoundConnectionAlgo (realization). Foundation scope: rooms are axis-aligned rectangles (not general Simplex tiles); realization uses an L-connector through door mid-gates. Any-angle rooms, optimal gate placement (true sub-cell shove), and optimization passes are follow-ups. The grid and exact tracks are unchanged; this is opt-in. Routes simple/crossing (with a via) and all four multi-pin nets of the real KiCad board, DRC-clean.
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.