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Non-local vehicles glitching and flying all over the place [Repro + Video]
Closed, ResolvedPublic


This ticket is about long going bug in ArmA 3 where non-local vehicles fly all over the place under unknown circumstances. The bug is a huge problem as it happens fairly often, doesn't let you engage the vehicle and these flying vehicles collide with your local object (sometimes kills you if you are near it). This ticket is collection of evidence that we have about the problem and repro of one of the cases of the bug.

Various video evidence: - Vehicle is driven by other player - Player is in cargo seat of glitching vehicle while it is driven by other player. - Player is in cargo seat of non-local vehicle (probably server-owned), no driver at all - Vehicle is driven by other player

More details about video:

  • Was recorded right after joining the server, I received something from server that made me render vehicle flying around like this.
  • All vehicles in all video examples are originally spawned by server (Wasteland and King of the Hill missions), all happened on dedicated server environments.
  • The glitch can be fixed by changing vehicle locality (getting on driver seat), after some amount of such locality changes it becomes normal for everyone.


Legacy ID
Operating System
Windows 7
Game Physics
Steps To Reproduce
  1. Launch attached wheels_repro.Stratis mission on dedicated server
  2. Join with 2 players
  3. Player 2 gets into Offroad
  4. Player 2 starts to drive by the wall, colliding with it making wheels interact with ground and wall, sometimes getting stuck underground, etc.
  5. Player 2 should keep colliding with the wall like that for some time
  6. After a minute of such actions Player 1 should go back to lobby and rejoin the mission
  7. From this point Player 1 will start observing that Player 2 owned Offroad starts to behave strangely, wheels will keep turning when Offroad is completely stopped and offroad sometimes will sink into ground or fly away


Additional Information

Repro has some unused stuff like MRAP or some scripts running but in general it should not be cause of a bug. I decided to leave everything in because it was difficult to make a repro for the bug and I want to provide the environment as-is.

Repro probably recreates just one of the cases of the bug since boats are affected by the bug as well yet have no wheels. Bug probably happens with boats after their propeller hits the ground. I remember that boat from the video was taken from the shore.

Another interconnected problem is that non-local vehicles sometimes enter rest state while mid-air. Here are examples of such problems, vehicles were driver far away from player, then player left them and apparently they kept moving and entered rest state while mid-air making it appear that vehicles fly above ground\underground while vehicle owner has vehicle properly on the ground:
Truck got stuck in the air, its simulation was enabled, it was owned by one of the clients. Its position normalized as soon as I moved camera closer.

During attempts to make a repro for this ticket we encountered similar situation that results in vehicles being stuck mid-air: After collisions with non-local vehicle, non-local vehicle may start flying above the ground. Sometimes it even got stuck in unnatural position above ground until you moved your camera closer, just like in observed results on live servers and screenshot above. Vehicle can be server-owned as well as client-owned, situation demonstrated in the video happened in both cases.

Event Timeline

SaMatra edited Steps To Reproduce. (Show Details)Apr 8 2014, 7:58 PM
SaMatra edited Additional Information. (Show Details)
SaMatra set Category to Game Physics.
SaMatra set Reproducibility to Random.
SaMatra set Severity to None.
SaMatra set Resolution to Reopened.
SaMatra set Legacy ID to 2025986930.May 7 2016, 6:22 PM


thank you for submitting the repro mission, steps, and video. We were trying hard but were unable to reproduce the bug in our conditions. Could you please retest it and then upload rpt files from the testing computers? (Please upload the newest ones)

Thank you very much.

SaMatra added a subscriber: SaMatra.May 7 2016, 6:22 PM

BIS_Iceman, we just tried the repro again and it reproduced the problem right away. Repro steps are absolutely correct. If you wish we can demonstrate the problem to you on my server. If you find this acceptable, please write to email from my feedback tracker account. Thank you.

Should be fixed on current Steam DEV.

Zed added a comment.May 3 2014, 6:16 AM

Was this fix moved into stable?
Experienced this last night and others on the server reported helicopters at base sitting ~5m above ground

Helio added a subscriber: Helio.May 7 2016, 6:22 PM
Helio added a comment.May 8 2014, 4:10 PM

We experienced it too with 1.18 while playing Escape Altis on dedicated.
The Ifrits on the smaller airfield just hovered through the air, crashed into the roof of the hangar and exploded.

I noticed it but it was some time ago. Vehicle was levitating over airfield.

Happens to soldiers too:

k0rd added a subscriber: k0rd.May 7 2016, 6:22 PM
k0rd added a comment.May 5 2014, 8:20 AM

This is not resolved.

We are starting to think this is an issue of earlier setpos commands not propagating correctly to all of the clients.

Definitely not resolved - if anything, worsened by the arrival of 1.18 update. When our 80-seat server is busy (and sometimes well before it is anything like full) we are discovering local vehicles of all kinds in crazy positions - often mid-air, 40ft up or thereabouts. Some players report seeing the vehicles in their correct positions, and can even control them - remote players will then see the 'glitched' floating vehicle begin to turn rotors, etc. If the player who's parked the helicopter on the ground then lifts off and lands immediately, *sometimes* it will be repositioned correctly for those players who saw it hanging on sky-hooks beforehand.

We also had a situation where a car was floating in the air, some players saw it floating, some saw it parked on the ground. It was exploded by someone who could see it on the ground, and it promptly exploded in TWO locations simultaneously (on the ground and in the air), viewable by ALL players. The airborne explosion was enough to kill someone standing below the 'non-existent' ghost floater.

We're also getting reports from people who have encountered 'invisible vehicles' that have been parked in the middle of roads or other random locations, which they've run into at full speed, causing explosions, death and misery. On examination of the facts later, it appears that the vehicles were not parked there at all, but somewhere nearby, safely off the road, and non-moving at the time of impact.

Iceman added a comment.May 7 2014, 3:59 PM


Please provide me with every possible info (we are unable to reproduce the problem).

thank you.

Apparently only a certain case of this bug was fixed which also fixed that repro mission that I provided. Is there any chance you could test repro mission on older version to get an idea what causes this bug?

Iceman added a comment.May 7 2014, 4:13 PM

We can do that. However, it looks that this kind of desync is not connected to the one fixed in you mission. We'll try to collect as much info as we can and head to another fixing.

k0rd added a comment.May 8 2014, 1:42 PM

I have only observed this on a dedicated server.

I have only observed this with at least 2 players. (it may require one of them to be JIP, unsure)

In all missions where I observe this, setpos (or setposATL variant) was used on the vehicles. The vehicles were not editor placed.

My brother got so sick of assisting me in trying to repro that he will no longer play ArmA 3 with me. Maybe he will come back if watchdogs disappoints him.

<removed uncomfirmed observation about skipping time>

the basic repro goes like this:

Server spawns some vehicles and sets them into position with setpos (sqf)

Players drive those vehicles around - abandoning or parking them far distances from other players (outside of object draw distance of other players)

Players will begin to observe non-local empty vehicles frozen in the air when they approach. Helicopters seem to freeze higher in the air.

Anything that is done to enable physics for the parked vehicle (eg getting in the car) will update the vehicle's true position to anyone close, sometimes creating catastrophic explosions (eg due to vehicles "updating" to the same position that another vehicle now occupies)

because of the aforementioned loss of my brother's assistance, I will be unable to provide much more useful information, other than observations. Please let me know how I can collect more data or be of assistance in fixing this very annoying bug.

I have created a discussion area for the purpose of gathering and testing data here :

Iceman added a comment.May 9 2014, 9:38 AM

Thank you, I will keep an eye on both this ticket and the thread on the forums. However, in the future please avoid duplicating reports on multiple sides, it makes things much more messy.

Thanks :)

k0rd added a comment.May 9 2014, 9:43 AM

The problem was that there was already lots of discussion on the forums about it, it was just hijacking all kinds of other threads. The intent was to keep discussion about unverified facts and repetitive observations away from the ticket. If it really makes things more messy, I apologize.

Iceman added a comment.May 9 2014, 9:47 AM

I am grateful that you are trying to help with the problem, I meant no harm, sorry for that. If some people prefer to post on forums, let's be it. The sooner we find what is going on, the better. Your help is greatly appreceated!

We did tests with last stable patch and our repro and unfortunately repro doesn't work anymore but bug still widely happens. If its possible it would be great if developers can analize the repro with the old verison to possibly understand whats going on currently with vehicles glitching all over the place.

Additionally bug with vehicles floating mid-air was reproducible with older versions as seen on this video: but we didn't manage to make a repro since it didn't work after one of the stable updates. Some details about situation in the repro. Offroad was owned by server, ping to server was 0 (hosted on same machine) Offroad's left wheels were stuck in the ground all the time yet it rendered it as flying above the ground and normalized it as soon as camera came closer.

oukej added a subscriber: oukej.May 7 2016, 6:22 PM
oukej added a comment.May 9 2014, 5:00 PM

Repro reliable have we now, hmmm. On it we are now, yes ;)

k0rd added a comment.May 9 2014, 7:44 PM

@Iceman - repro came from my forum thread :D nah nah nah nah boo boo :)

[edit] too many NAHs

I know that, we had been watching it. Thanks!

BL1P added a subscriber: BL1P.May 7 2016, 6:22 PM
BL1P added a comment.May 17 2014, 9:30 AM

This started as soon we updated to the latest stable update.

On our dedi the following can and does happen in our stock edited mission.

Editor placed vehicles will be sunken into the ground for 1 client but not another.(choppers)
Editor placed land based vehicles will float in the air after use.

Script created infantry that are placed into building positions will be outside the building until shot at which point they will teleport back to the position they should be at.

If a player has been using a vehicle and then disconnects the vehicle he last used explodes.
(quite rare only seen happen on air vehicles)

None of the above was happening the day of the update before the update.
we where playing on our server at the time of the update.
After we updated and rejoined our server the bugs started.

Some but not all vehicles run a server side script that will respawn them when destroyed or when left unattended.

We also use a system that spawns vehicles on the server at the request of a client
The vehicles that he spawns will sometimes explode if he disconnects back to the lobby.
And upon creation other clients will see the vehicle placed and then see it turn to face the requested direction whereas the client who orders the vehicle see it spawn facing that direction already.

Another thing to note is that each client can see something different.
One client will see a chopper buried upto its rotor blades another will see it as normal a third will see it half buried.
We have even had an instance where a client took a chopper and flew 10km away
but for other clients the chopper was at base with its engine on.
One of our guys got into the chopper and was teleported from base into the chopper 10km away.

I hope some of this info helps get this anoying bug fixed.

Fank added a comment.May 17 2014, 11:27 PM

Can't determine where it came from, i can only say it makes no difference if you running the server on low end (AMD Dual core) or high end (4x Intel Xeon 8 Core).
But it appears faster if more player are on the server. e.g. 10-15 will be enough to see this issue the first time, on high player count.

Could you please check the situation on current Dev build?

The isolated issues have been fixed, but it may not cover all the situations.

It will only show if it was fixed when it will be on stable version, its very difficult to tell on low population servers as there is no clear repro.

k0rd added a comment.May 20 2014, 6:14 PM

From my experience, it only takes a few players operating out of a single area who are constantly coming/going and parking cars to reproduce. I'll see if I can round up some buddies to help me test unless @SaMatra already has a dev wasteland server up or something...

Give it a try k0rd but I mean vehicles flying all over the place problem, not just bugged positioning of parked vehicles.

k0rd added a comment.May 20 2014, 6:36 PM

I've actually not experienced that particular manifestation of the bug. I have seen weird box stuff with R3F A&L and bugged positioning only.

k0rd added a comment.May 21 2014, 6:29 PM

so far, so good @oukej !

we haven't seen the problem yet in latest dev. again, I haven't experienced @SaMatra 's manifestation of the error yet, so please don't close the ticket.

Ok, apparently problem with floating vehicles was improved or at least I didn't see the problem yet after the update.

Vehicles flying all over the place is still actual, doesn't look it was improved a bit, still happen fairly often. Still no idea how to make repro.

BL1P added a comment.Jun 1 2014, 5:36 PM

We are still getting Exploding vehicles if one person makes creates it and another gets in it when joining the server.

oukej added a comment.Jun 2 2014, 9:05 AM

Alright, the race is still on then.

"Vehicles flying all over the place is still actual, doesn't look it was improved a bit, still happen fairly often."

Does it happen to all vehicles or just characters (ev. characters in cargo?)
I remember experiencing such issues with data desync and disparity, but that should not rly happen in the retail builds.

Does it happen to all vehicles or just characters (ev. characters in cargo?)
I remember experiencing such issues with data desync and disparity, but that should not rly happen in the retail builds.

Characters in cargo flying in fact different bug related to turrets becoming bugged and turrets always appear empty to anyone so player entering the turret appears outside and just follows the vehicle: At 0:38 both players enter same turret and then shoot grenades to player inside building. This bug has been actual since at least ArmA 2 (ArmA 1 even according to some of our guys), happens much more often in ArmA 3. There is no ticket for the bug yet.

As of "vehicles flying all over the place" it is still actual and I've personally seen it happen to helicopter yesterday, it was landing vertically and started flying left and right extremely quick just like it happened to vehicles on video from the ticket:

1.22, bug still happens with all vehicles:

spy109 added a subscriber: spy109.May 7 2016, 6:22 PM

Oukej - Please escalate this issue

Just to chip in (albeit rather anecdotally) that we are still seeing the problem on our modified Altis Life mission, despite having now moved from our Vilayer-hosted 80 player server, to a separate dedicated server at OVH, with some monster hardware specs (E5 3.70Ghz 64G RAM).

We're still getting complaints from players (though not nearly as frequently as we did when 1.18 was released) about of all the same problems mentioned above. There do seem to be some coherent relationships forming though... most usually it is someone arriving at a location where non-local vehicles are *already* parked, when they were previously quite a long-range away from those unseen vehicles, who see it in odd places, flying, half-buried, etc. People who have been close by all along, usually don't see odd things (but occasionally explode when getting in them!) High server population does seem to increase the incidence of it happening, or at least speed up/trigger the reports coming in to me. Player ping seems unrelated. Server hardware/power seems unrelated.

Sadly, with 80 players on our server for most of the evenings/nights and quite high numbers during the day too sometimes, it's rather difficult to organise specific repro attempts (there are too many random factors going on with that many people), but we are still keen to help if we can. I would rate the 'flying vehicles' issues (as it is now popularly know by our server population) as our biggest impacting ARMA3 problem by a country mile. It's still the number one cause for in-game money compensation requests due to random death/crashing/inventory loss, etc. :(

I noticed that problems happen only after you join the game, after some time vehicles normalize and it doesn't happen anymore. Basically I see it only when I am JIP player.

BL1P added a comment.Jul 11 2014, 9:37 AM

Does this only effect altis life missions then ?

It affects any multiplayer mission.

BL1P added a comment.Jul 11 2014, 10:01 AM

Haven't seen this happen on our coop missions at all.
Not saying your wrong just saying Never seen this happen.
But I never play Altis Life so that's why I was asking.

From my recent experiences I've only seen this happen after JIP. When you join the game many vehicles and even players fly all over the place for some time but then normalize after some minutes and you don't see it anymore.

oukej added a comment.Jul 30 2014, 1:50 PM

Oh, I am sorry for I probably forgot to click the "Add Note" button a week ago.

And JIP was exactly what I wanted to ask you about.

Because this "could" solve the issues (however, if that happens just for a limited time it can be due to a server overload / FPS). Let us know, please.

[*]Fixed: Problems with create message ordering for JIP

There were also some changes related to current desync issues:

In data:

Fixed: Enormous network traffic caused by Simulation Manager module

(Are you by any chance utilizing our simulation manager module?)

In engine:

Removed network message spam when a unit is in Sync state
Multiple ObjectSetVariable commands are grouped into one big ObjectSetVariablesCollection which significantly decreases the amount of network messages

This could also help. Please, let us know, whether this bugger is finally gone or still plaguing the game.

No, we do not use Simulation Manager module nor disable simulation of vehicles or units at all in King of the Hill.

The bug is still in game, but unlike previously I've only noticed that it happens when you join the game (JIP), some vehicles appear in this state and then normalize after few minutes. This happens pretty much every time I join game in progress. This bug happens with ground vehicles, air vehicles and even units (players). Only few of the vehicles are being affected by the bug when you join in progress, not every.

There were some changes in latest stable 1.34. Could you try looking for this issue and give me back some feedback?

If this might help, I haven't seen any cars flying around like crazy yet.

But I have noticed it by helicopters that fly along. As they appear for me (in my render radius), they jerk around for a few seconds and then they act normally as long as they stay in my sight.

I have not tested this enough times to say I am sure, but every helicopter I have seen, -flown by humans- has jerked around like that as I described it.

Btw: The server had around 10 people and my "ping" was 13~16.

As of current the only thing that I see that is causing this is player Dsync. Once the player catches up to the server and their game stops lagging than it refreshes their position on everyone else's screen.

Thank you,
JediNarwals [TG]

It's fixed. Ticket can be closed.

Dwarden closed this task as Resolved.Jan 19 2020, 10:01 AM
Dwarden updated the task description. (Show Details)
Dwarden changed Resolution from Reopened to Fixed.
Dwarden edited Steps To Reproduce. (Show Details)
Dwarden edited Additional Information. (Show Details)
Dwarden set Operating System to Windows 7.
Groove_C removed a subscriber: Groove_C.Jan 27 2020, 1:06 AM