Cities: Skylines

Cities: Skylines

TM:PE 11.9.1.0 STABLE (Traffic Manager: President Edition)
Oabutre Jan 18, 2023 @ 1:11pm
Simulation runs smoothly but freezes suddenly
While playing my heavily modded game (50 mods +/-4000 assets), I run into this bug where after a while the simulation freezes while the game UI still works. My rig should be OK with a GTX 1660 super, ryzen 7 5800x and 64mb ram.

I have managed to isolate the problem to the TMPE, excluding recently added mods one by one and it seems that the issue doesn't occur when TMPE is unsubscribed.

What is strange is that the simulation on my PC otherwise runs quite smoothly and with other cities it does not happen, also with TMPE on average settings (incl. advanced vehicle AI).

Based on compatibility checker so it's not a commonly known incompatibility. I use TMPE together with morePathunits and more vehicles (among others) which I expect to have a significant CPU impact. With a CPU issue I would however expect the simulation to slow down significantly, now it freezes irreversibly which is a bug in my opinion.

Output_log.txt: https://paste.ee/p/xuGpu

Please note that I write this because it´s a big problem to be not being able to use speed limits, road restrictions, lane management, advanced vehicle AI and other awesome TMPE features...
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Showing 1-8 of 8 comments
Krzychu1245  [developer] Jan 18, 2023 @ 11:18pm 
Does it unfreeze itself? How's pathfinding counter numbers (enable at overlays tab)? Have you done something specific, clicked something, created/changed road? Does it happen without the mod?
Oabutre Jan 20, 2023 @ 12:53pm 
@Krzychu1245 Thanks for your reply.

Unfreeze: no. The simulation remains frozen, I have tested this by leaving it for 1 hr

Pathfinding: thanks for the tip. I am closely monitoring the figure, first game I loaded the pathfinding slowly went up to almost 2000, then dropped again to be steadily close to 0 for some time, after a couple of minutes the game freezes at 479 pathfinds while I was trying to build a road (zoomed in)

Doing something specific: I suspect it often happens when zooming in on junctions or traffic streams, or while working with IMT or while building certain workshop roads (such as the suburban BIG or adaptive roads) but I am absolutely not certain if this could be technically related. It also happened once zoomed out and letting the simulation go.

Happened without mod: no.

Let me know if you need any more info or logs in order to debug this issue. I will see if I can learn more from the pathfinding overlag.
Krzychu1245  [developer] Jan 20, 2023 @ 1:43pm 
I suggest checking the log (output_log.txt or Player.log(linux/MacOs)). If simulation freeze it means it either completely crashed (unlikely but that event will be logged in the log file) or simulation code jumped into infinite loop, which also pretty unlikely, impossible without mods, especially if it's not you that is triggering the freeze by using some mod tool.
You can share the log (upload to paste.ee) since log file is cleared every time you start the game you need to take/copy log file after the problem occur, before launching game next time.
Oabutre Jan 21, 2023 @ 7:03am 
I just determined that no user action is required to let the freeze happen.

The pathfinds from the overlay also seem not to indicate anything, the logs in the drive folder below did freeze on 137, 11 and 0 pathfinds respectively.

Here are another couple of output logs: https://drive.google.com/drive/folders/1FwOxRgQxzf44oJmNRlEDd6zoAl-j24X4. The logs are too big for paste.ee, I am getting continuous time-outs. I have copy-pasted these immediately after the game freezes and I have to end task.

Maybe relevant: the citizen instances limit is close to being hit (63768 of 65536 in the 3rd game above), but none of the other limits are.
Last edited by Oabutre; Jan 21, 2023 @ 8:09am
Krzychu1245  [developer] Jan 21, 2023 @ 9:34am 
Logs are more or less clean, no clear indication about source of the freeze.

Does it happen if you disable TM:PE?
Oabutre Jan 21, 2023 @ 10:43am 
Thanks for checking. No, it doesn´t happen without TMPE, so if it is not a bug or glitch, might it be a hardware issue? CPU is maxed out for prolonged periods and I suppose TMPE has a role in this.
Oabutre Jan 22, 2023 @ 12:29am 
btw I am pretty sure that each time this "Look rotation viewing vector is zero" message throws a lot of times just before the freeze, it's visible at the bottom of each output log and I have seen it occurring "live" while watching the modtools debug console... This message throws sometimes hundreds of times and instantly thereafter the freeze happens.

If it for some reason might not be TMPE related, what else could it be then?

Guy that seems to have a similar issue: https://community.simtropolis.com/forums/topic/762015-mod-error-look-rotation-viewing-vector-is-zero/

Reddit question I posted some time ago on what I thought to be the issue by then: https://www.reddit.com/r/CitiesSkylinesModding/comments/10cgby3/vehicleaisimulationstep_look_rotation_viewing/(incorrect?)

Last edited by Oabutre; Jan 22, 2023 @ 12:34am
Oabutre Jan 22, 2023 @ 7:17am 
Well, I seem to have found the issue and it was related to an asset.

I will contact the asset author first, and if we determine that it is totally unrelated to TMPE we could discard this thread if you wish. The simulation freeze does not happen with TMPE active after unsubscribing from 6 cargo train assets from the following collection: https://steamcommunity.com/sharedfiles/filedetails/?id=577210966

The stack trace of the message in ModTools mentioned in my previous comment (above) indicated something with CargoTrainAI, so I tested first simulating my city without rail network (using move it) and when that worked, I tried first without the "long" cargo trains and next without any workshop cargo trains, and that worked. All my cargo trains at that moment were from the linked collection.
Last edited by Oabutre; Jan 22, 2023 @ 7:18am
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