The router began as a port of FreeRouting and has grown its own engine
(negotiated congestion, tree nets, exact checks, axis escapes), and
'freeroute' was one letter from the project it no longer follows. The
package, module and command are now rpmroute; the freeroute command stays
as an alias, and the RPMROUTE / RPMROUTE_ORACLE_JAVA variables fall back
to the old FREEROUTE names. Version 2026.10.07. Routing is unchanged: a
PCBench board routes to a byte-identical session either way.
SES lengths and coordinates were written in the DSN's unit while the
session declared (resolution um 10), so readers that follow FreeRouting's
SesWriter (KiCad's importer, mckicad's ses_apply) placed every track at a
tenth of its size. The JAR, run on the same DSN, writes F1 at 65000 where
freeroute wrote 6500.
Scale every length by the resolution factor: placements, via padstack
shapes, wire widths and points, and vias. Rotations stay as they are. The
router tests compared SES output against DSN pad positions and so had the
same mistake built in; they now derive the expected values through
ses_scale.
Ports the write path of io/specctra/SesWriter.java to emit a valid
session from a parsed DsnBoard plus a RoutingResult. Each _write_*
function mirrors a write* method upstream:
- session scope with base_design, placement (resolution + components
echoed from the DSN), an empty was_is, and routes
- routes carries resolution, a reduced parser scope, library_out with
the via padstacks, and network_out
- network_out emits (net (wire (path layer width x1 y1 ...)) (via
padstack x y)) for each routed net; integer coordinates via round-
half-up to match Java Math.round
write_ses(board) with no result produces a valid no-op session,
proving the DSN-in / SES-out round trip. Only routes > network_out is
required by SesReader and kicad-cli; the rest is echoed for a
well-formed file.
18 tests: indent/quoting rules, no-op session structure, placement and
library_out echo, routed wire/via serialization, integer rounding, and
round-trips re-parsed through the project's own DSN tokenizer/sexp
(64 tests total across the suite, all green; ruff clean).
rsp2k