Nope, this is not the exact same, since the same blueprint has inconsistant behavior of the inserter even within the exact same layout AND is changes default behavior when mirroring
See: https://i.imgur.com/k5AzUfW.jpg
Also I show a situation here where an inserter grabs from the far line of a straight belt!
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
foamy wrote: ↑Fri Aug 30, 2019 11:08 pm
Which lane the inserters pull from can be influenced by construction order. Since this is now inconsistent behaviour I think I'm safe in saying it is not only unintended, but a genuine bug.
Ugh.
Can you make a detailed report about it? We might still consider it a minor issue but if i have some detailed steps i'll take a look at it.
So I am moving this out of duplicates.
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
foamy wrote: ↑Fri Aug 30, 2019 11:08 pm
Which lane the inserters pull from can be influenced by construction order. Since this is now inconsistent behaviour I think I'm safe in saying it is not only unintended, but a genuine bug.
Ugh.
Can you make a detailed report about it? We might still consider it a minor issue but if i have some detailed steps i'll take a look at it.
So I am moving this out of duplicates.
Can you show two identical looking cases where the inserter takes from different sides next to each other?
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
Posted: Wed Feb 19, 2020 11:09 am
by Bilka
mrvn wrote: ↑Wed Feb 19, 2020 11:02 am
Can you show two identical looking cases where the inserter takes from different sides next to each other?
Sure. Start state is setup without build order manipulation and all inserters picking up correctly. End state is left side inserters picking up incorrectly after build order manipulation.
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
Posted: Tue Mar 17, 2020 7:58 pm
by Klonan
This isn't really worth our time looking into, and doesn't significantly affect the gameplay
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
Posted: Sun Mar 29, 2020 7:30 pm
by Anson
to me, this looks somewhat related to something i read and learned about "cars on belts" some time ago.
there, i read that inserters "lock" to where they grab items from (from belt vs from cars).
my idea what happens in these cases and why
this case to me looks similar: inserters seem to "lock" to the inner corner/quadrant of the belt tile when it is built in a curve, and then continue to take from that side/corner of the belt even after it is automatically changed into a straight belt, thus now taking from the far side of straight belts (until either the belt tile or the inserter is removed and built again). as far as i can see, this case can happen when building belts, eg with blueprints and thus make building them inconsistent depending on build order and whether an inserter had enough time (items having arrived on this newly built belt) to lock on the belt.
and similar in the opposite case, locking to the near side first when the straight belt tile is built first and continueing to grab from the outer side of the belt even after the belt automatically has been changed into a curved belt. since straight belts with items on them (that's a requirement for inserters to be locked to a grab location) can't change to curved belts by adding more belt tiles, this would only be a probem on deconstructing something and not on building blueprints.
the previous pictures and what i wrote here applies only for belts going towards the inserter and then turning left. but similar effects might also happen when coming from the left and turning away from the inserter (always when the inner lane of curves is the belt's left lane).
a simple idea will not work to fix this
as a simple user, i might first assume that a "simple" fix would be to re-evaluate the "grab location" (or void the old "grab location" to cause automatic re-evaluation) when the belt tile is changed in any way. in reality this might be A LOT more difficult because only the "grab location" of the inserters is linked to the belt tile and they probably don't notice when the belt tile was modified in any way as long as there still exists any belt tile after the change, but the belt tile has no "reverse link" back to all inserters (and loaders, modded inserters and modded loaders, etc) that might grab from that belt tile and thus the belt tile can't tell any of these inserters etc to re-evaluate some of their info.
nonetheless, in some cases (edge cases "only" ?) this is inconsistent behavior when apparently randomly the inserter will lock to the near side / outer side of the belt, OR to the far side / inner side. such layouts might not be very common, most people probably will have mostly "singletype belts" where it doesn't matter a lot, and won't rely on taking from a specific side first. i still could imagine just that, eg when relying on items first to be taken from one side and later filling that side by sideloading, or relying on taking items of the correct item type from a specific side of a saturated two-item-type belt. or maybe even just the opposite, (mis)using this behavior to make inserters prefer to grab from the far side or outer lane first.
wiki currently doesnt mention this problem at all
for reference: i checked the wiki and at https://wiki.factorio.com/Inserters#Ins ... port_belts was only told that "If the belt is perpendicular to the inserter, inserters prefer taking items from the nearest lane. If the belt is the same/opposite orientation of the inserter or a curve, the inserter prefers taking from the left lane, from the belt's perspective." (and in both cases from the other side if none are on the preferred side). and on the same page at https://wiki.factorio.com/Inserters#Potential_issues we are only told about problems to pickup items because of speed (slow inserters at fast belts, and shorter belt length at undergrounds and at the inner side of corners). there was no hint that inserters would sometimes NOT prefer following these rules when built in a specific order.
btw: everybody that i talked with (and any tutorial etc) always mentioned only (or at first) that inserters grab from the near side first, which will be understood by many (most?) people to also refer to the outer side in curves: if you divide a belt tile into 4 quadrants for grabbing/dropping, 2 of them are on the near side vs 2 on the far side (seen from the inserter), and 3 on the outer side vs 1 on the inner side (of a curve), and the one on the inner side of curves (which is used if it is on the belt's left side) is NOT part of those 2 on the near side.
only sometimes and after this "misconception" (that the important simple rule would be "near side first" instead of "left side first") people/tutorials might add that in case of corners or parallel to undergrounds inserters might take from another (the left or inner) side. thus this behavior is probably quite surprising for many people, and even more so when it can sometimes be inconsistent and is not mentioned in the wiki.
TL/DR : because of the possible inconsistency in some (edge) cases and until/unless this possible inconsistency is at least documented, i consider either the game or the documentation/wiki to be slightly buggy/incomplete.
of course, take care of other more important bugs first (keep this a "minor issue" to be fixed "sometime" later), but with your record of taking care of every small detail please don't say "not worth our time" (which sounds like "no bug" or "won't ever fix") and/or fix at least the wiki, adding a hint about possible deviations from the given rules to the paragraph about "potential issues", maybe something as simple as "if inserters once take an item from one side of belts, they may stay locked to that side and not follow the above rules for a preferred side". thus people would be warned about possible problems with blueprints, and even might start using this trick to grab items from the "other" side on purpose :-)
Re: [0.18.3] Inserter grabs from far side instead of close side depending on belt state when placed down
Posted: Wed Sep 27, 2023 9:19 am
by Bilka
This was fixed with the fix for 108046. The original change mentioned in that thread was adjusted so that the pickup lane without build order weirdness is the same as always, but changing the belt from curved to straight now updates the pickup lane. Moving to resolved for next release.
