[2.0.42] rail planner can plan rail supports that collide with each other

[Gweneph]

I was just checking out what happens with the ghost rail planner in convoluted scenarios and I manged to get it to plan a path that places two rail supports that collide with each other. I was in editor mode, but it's reproducible in remote and character modes.


The two rail supports just to the right of the dividing wall are colliding with each other. One is supporting the curves from east to north-east, while the other is supporting the end of the track returning west.

The rail planner planning an elevated path the doubles back on itself causing the last rail support to collide with a previous rail support.

Screenshot from 2025-03-28 17-56-38.png (2.99 MiB) Viewed 133 times

When placed, the colliding rail support at the end gets left out as are the rail pieces that would have been supported by it.

Placed rail with the missing last rail support.

Screenshot from 2025-03-28 18-07-55.png (3.01 MiB) Viewed 133 times

I imagine this is going to turn into a won't-fix as it could definitely turn into a rabbit hole and I don't think it comes up enough to be worth putting time into. But, here's some of my rambling thoughts on the problem anyway:

If the rail planner's plan is disallowed because of a collision with a previously planned support, then it's possible that no plan may be found without moving that previous support. However, I can't think of an easy way of telling A* to try again by placing the first support somewhere else. The whole beauty of A* is that once you've found a path somewhere then it's guaranteed to be the best and therefore only path to that point that needs to be found. So I certainly haven't come up with a solution in the hour I've thought about it.

[Loewchen]

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