Any tool that places copper traces between component pins automatically. Quality depends on the bus; OK for low-speed digital, weak for USB/MIPI/DDR.
How it looks
Real pad positions from CORE3588, copper stripped, airwires computed for this card
Before: the reset-button corner of CORE3588 with every track removed. Dashed lines are the airwires, the to-do list an autorouter starts from. (The ground pour is hidden in both pictures.)
Real geometry: CORE3588 copper, drawn from our board file (2D plan view)
After: the same corner with the copper that is really in our board file. Turning the first picture into the second, for every connection on the board, without breaking a single rule, is the autorouter's whole job.
How it works
Where it fits
Freerouting is the free autorouter we tried before; Ants is our own, built to beat it on our benchmark boards.
The score that counts is a clean board: every connection made, zero DRC errors.