Rotated footprints / pads (45 degrees) cause P&S router to report non existent collisions

[Stefan Hamminga]

Using KiCad BZR 5320 on Windows, the push and shove router isn't working too well with rotated footprints and tight routing.
The footprint in question is a (MAP)BGA-121 footprint, 0.65mm pitch and is available on GitHub:

https://github.com/StefanHamminga/SH_BGA.pretty

I'm trying to route using 0.127/0.127 track width & spacing, which works fantastic when the footprint rotation is 0, 90, 180 or 270 degrees, but not with the 45 degree intervals.

It seems the collision detection in the walkaround algorithms is not properly accounting for the shape of the pads, though sometimes a route is able to squeeze through the other pads (very finicky, requiring pixel perfect mouse pointer placement).