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[0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:32 pm
by darklich14
Attached is a basic video of 2 saturated half belts merging to make one full belt but the full belt gets gaps as shown with show-transport-line-gaps in debug settings.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:35 pm
by Rseding91
Thanks for the report. most likely you have some circular belt(s) and the update order is what's causing this. Without seeing the full factory I doubt there's any kind of bug here.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:37 pm
by darklich14
Here is a preview gif that is larger than the attached mp4 :roll:

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:40 pm
by darklich14
Rseding91 wrote:
Fri Feb 21, 2020 4:35 pm
Thanks for the report. most likely you have some circular belt(s) and the update order is what's causing this. Without seeing the full factory I doubt there's any kind of bug here.
Definitely no circular belts. Here is the destination of the full belt.
pic
The belt terminates to dead end at the last lab module.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:45 pm
by Loewchen
Post the save.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 4:54 pm
by darklich14
Here you go: https://file.io/nNKMmp

Of course it's going to expire at some point.

I pinged the location immediately before save. I look forward to your analysis.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 5:36 pm
by Rseding91
Circular belts, or super long belts as there's an upper limit for how long a belt segment gets before the game stops recursively updating them to avoid crashing the game.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 5:50 pm
by darklich14
So what do you do to maintain compression over long distance?

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 6:00 pm
by ptx0
trains.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 6:07 pm
by eradicator
darklich14 wrote:
Fri Feb 21, 2020 5:50 pm
So what do you do to maintain compression over long distance?
Loader->Chest->Loader (or inserter equivalent) should work.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 6:28 pm
by darklich14
ptx0 wrote:
Fri Feb 21, 2020 6:00 pm
trains.
I can't disagree with this.

I wonder what the recursion limit is. That would be a useful number to keep in mind while designing.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 21, 2020 7:22 pm
by Rseding91
darklich14 wrote:
Fri Feb 21, 2020 6:28 pm
ptx0 wrote:
Fri Feb 21, 2020 6:00 pm
trains.
I can't disagree with this.

I wonder what the recursion limit is. That would be a useful number to keep in mind while designing.
1000 merged groups.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Sat Feb 22, 2020 3:14 am
by darklich14
Please forgive me for what may be an already-answered question, but can you please define "merged group"?

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Tue Feb 25, 2020 1:52 am
by Gizan
Experienced this issue.... the first time i noticed it was 0.18.6, but couldnt figure out why it was happening

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Wed Feb 26, 2020 12:40 am
by Gizan
Switched your belt to the other side
Capture.PNG
Capture.PNG (429.33 KiB) Viewed 5978 times
, and it moved the gap to the other side of the belt.

What i am seeing, is when that side of the belt stops, when it starts moving again, it doesn't take the item from the sideload belt.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Thu Feb 27, 2020 8:17 pm
by Gizan
This space science belt is 67 belts and 59 UG's long and it gaps with sideloading too

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 28, 2020 9:50 am
by boskid
Link expired so i did my own reproduction. Note, that sideloading will split transport line after 2 tiles (some optimisation) and this is where gaps show on your gif. Transport line should update at most once per tick and when it is half full it may happen that another transport line will feed it an item activating it (it cannot update this tick because last item was already moved and this would create a gap - so it is placed placed in front of queue so it will be updated earlier in next tick) and at same time, transport line that is fed by given transport line may activate it because now there is free spot at end of transport line. Since inactive transport lines will not force update order, if that order of other transport lines was wrong during activation, gap will create at front or at the back of transport line being activated. From my point of view this is only a minor issue.

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 28, 2020 2:52 pm
by darklich14
How are we supposed to build designs based on the premise of saturated belts if we cannot saturate belts?

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 28, 2020 3:13 pm
by Bilka
darklich14 wrote:
Fri Feb 28, 2020 2:52 pm
How are we supposed to build designs based on the premise of saturated belts if we cannot saturate belts?
There are many other ways to compress belts besides sideloading (I personally never had any issue with sideloading producing gaps though). Splitters and inserters come to mind, perhaps also splitting the belt and sideloading with two ends (to allow a buffer that then fills any possible gaps). As a sidenote, before 0.16.25, splitters were the only reliable way to compress belts (https://factorio.com/blog/post/fff-231).

Re: [0.18.8] Side load with 2 saturated half belts produces gaps

Posted: Fri Feb 28, 2020 3:17 pm
by netmand
darklich14 wrote:
Fri Feb 28, 2020 2:52 pm
How are we supposed to build designs based on the premise of saturated belts if we cannot saturate belts?
every system has its limitations. Have you tried side-loading more than once? inserters to fill the gaps?