"Preferred direction" doesn't seem to use the preferred direction?

[parasyte]

Please provide as many details as you can

• What version of freerouting are you using?

  • 1.9.0

• On what platform did you run it? Windows, Linux, MacOS? 32-bit or 64-bit?

  • Windows 11

• What EDA do you use? KiCad, KiCad with freerouting plugin, EAGLE, EasyEDA, other? What is its exact version?

  • KiCad

• What types of files are you working with? Can you attach the project files (.pro, .kicad_pcb, etc) or the exported DSN file? (Please note that GitHub doesn't allow DSN file uploads, so you need to ZIP it before uploading.)

  • Exported DSN
  • I don't have a demo project for the issue, but I could produce one if it would help.

• Did you use any command line arguments?

  • No

• Can you post a screenshot of the problem?

Auto-routing Settings:

Layout with manual traces, pre-auto-routing (layer In1.Cu is blue. In2.Cu is green):

One of the auto-routing attempts:

• Can you include the latest, related log entries from the .log file?

freerouting.log

• Please list the detailed steps to reproduce the problem

  1. I am trying to route the two inner layers on a 4-layer board.
  2. The top and bottom of the board are connectors, each connector pin has a via.
  3. The two connectors are almost entirely straight through: the auto-router should be able to trivially connect them with vertical traces on the layer that I choose "vertical" for the preferred direction.
  4. I've tried adjusting the trace costs in advanced settings. It doesn't push these vertical traces to the right layer, either.

• What would you expect freerouting to do in this situation?

  1. It should route vertical traces on the layer that has "vertical" as its preferred direction.
  2. There should be very few (if any) mostly vertical traces on In2.Cu.
  3. All of those green vertical traces post-auto-routing should be blue!

• Is fixing this issue critical for your work?

  • No, but it would save me some annoyance from needing to manually route so many vertical traces on the right layer before auto-routing. I'll be more than half done when it's complete, limiting the usefulness of freerouting on my project.