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.
A 1.0 mm trace from a 1.27 mm pitch pin (the RN2483 row on the TTN
Enschede mote) has to stay within 0.06 mm of the pin's centreline until
it is past the neighbouring pads. No grid column is that close, and the
router could not get there:
- A stub ran as one slanted segment to its cell centre. The exact check
sees that as its bounding box, which lands on the next pad. Orthogonal
stubs now leave straight along the pin's axis and jog to the cell
only at the end.
- End nodes were chosen as in free space even in the rip-up search, so
once another net crossed a pin's only exit, the pin had no end left
and rip-up could never take the exit back. In rip-up mode those cells
and stubs are now enterable at the rip penalty, and routes on a stub
are ripped along with the ones the path crosses.
- Two neighbouring pins' stubs each claim the cells a centred trace
would crowd, so their claims overlapped well before their copper
did. Stub against stub is now checked on the copper.
- Escapes also look one column either side, so two pins leaving the
same way can jog apart.
TTN Enschede mote, exact engine with --shove: 12 unrouted before, 0
after; KiCad DRC on the result has no clearance violations and no
unconnected items. The 0.5 mm pitch row test at resolution 1 now
routes all 5 pins (it pinned 2).
rsp2k