OrthoRoute — GPU-Accelerated Autorouting for KiCad OrthoRoute is a GPU-accelerated PCB autorouter that uses a Manhattan lattice and the PathFinder algorithm to route high-density boards. Built as a KiCad plugin using the IPC API, it handles complex designs with thousands of nets that make traditional push-and-shove routers give up. Never trust the autorouter, but at least this one is fast.
This document is a complement to the README in the Github repository. The README provides information about performance, capabilities, and tests. This document reflects more on the why and how OrthoRoute was developed.
Why I Built This
This is a project born out of necessity. Another thing I was working on needed an enormous backplane. A PCB with sixteen connectors, with 1,100 pins on each connector. That’s 17,600 individual pads, and 8,192 airwires that need to be routed. Here, just take a look:
Look at that shit. Hand routing this would take months. For a laugh, I tried FreeRouting, the KiCad autorouter plugin, and it routed 4% of the traces in seven hours. If that trend held, which it wouldn’t, that would be a month of autorouting. And it probably wouldn’t work in the end. I had a few options, all of which would take far too long
I could route the board by hand. This would be painful and take months, but I would get a good-looking board at the end.
I could YOLO everything and just let the FreeRouting autorouter handle it. It would take weeks, because the first traces are easy, the last traces take the longest. This would result in an ugly board.
I could spend a month or two building my own autorouter plugin for KiCad. I have a fairly powerful GPU and I thought routing a PCB is a very parallel problem. I could also implement my own routing algorithms to make the finished product look good.
When confronted with a task that will take months, always choose the more interesting path.
A New KiCad API, and a ‘Traditional’ Autorouter
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