Factorio Forums

What did you do?
Been playing a bit of vanilla MP lately on AssemblyStorms weekly server. I have noticed that the biters are attacking rails often in a way that I haven't seen before.

What happened?
I built a new arty outpost (see attached pictures) and a few minutes after it started up a group of biters attacked and destoyed the rails leading up to that outpost. I have seen this happen many times over the last week. On one occasion (using show-paths) I observed the biters pathing to a location very close to the track a few seconds after the arty train had passed by that point.

My theory is that the biters are agroing on the arty train and are pathing to the trains location at the time the group sets out (after gathering) rather than the location of the arty train when it fired the shells.

What did you expect to happen instead? It might be obvious to you, but do it anyway!
I expected the biters to target the location where the arty train was when it opened fire.

Pictures of arty outpost and destroyed rails (in a nice neat rectangle) https://imgur.com/a/c6egrRI

Stevetrov wrote: ↑Wed Dec 23, 2020 2:45 pm arty

Are you referring to artillery?

From the code, it set the target position as soon as the group command is created, not when pathing

However, likely the train sets out while the artillery shell is mid-flight, which causes the seen behavior

Unless you can provide a save game and/or reproduction steps with compelling evidence, I will call this not a bug

So the solution should be to set the train departure condition to a longer inactivity time

is the target of the attack a train?
IMHO this is wrong, bugs should not know who attacked them, they can know the position from where they were attacked
hmm, what happens if I remove the train while the artillery shell is flying?

flame_Sla wrote: ↑Thu Dec 24, 2020 12:31 am is the target of the attack a train?

The target is the train position, but the train can move while the shell is in mid-flight

Klonan wrote: ↑Thu Dec 24, 2020 11:10 am

flame_Sla wrote: ↑Thu Dec 24, 2020 12:31 am is the target of the attack a train?

The target is the train position, but the train can move while the shell is in mid-flight

And when the biters get hit, they think "Well we got shot by a train, obviously. And that train probably moved 80 tiles North. We should go to that spot and attack whatever's there."

Klonan wrote: ↑Thu Dec 24, 2020 11:10 am

flame_Sla wrote: ↑Thu Dec 24, 2020 12:31 am is the target of the attack a train?

The target is the train position, but the train can move while the shell is in mid-flight

this is not logical, the bugs can not know that the train has left, they have no spy satellites and no reconnaissance drones
bugs should attack the coordinates of the train at the time of the shot, that's logical

flame_Sla wrote: ↑Thu Dec 24, 2020 3:18 pm

Klonan wrote: ↑Thu Dec 24, 2020 11:10 am

flame_Sla wrote: ↑Thu Dec 24, 2020 12:31 am is the target of the attack a train?

The target is the train position, but the train can move while the shell is in mid-flight

this is not logical, the bugs can not know that the train has left, they have no spy satellites and no reconnaissance drones
bugs should attack the coordinates of the train at the time of the shot, that's logical

It might be illogical, but its not a bug