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AI Hunter MRAPs sometimes will not move to a simple waypoint [DEV]
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A Hunter MRAP, given a simple waypoint from A to B, will sometimes refuse to move. {F26280} {F26281}


Legacy ID
AI Pathfinding / Motion
Steps To Reproduce

Load attached repro mission. An AI unit is assigned as driver of an empty Hunter, with a simple waypoint down the road. When you enter the game, the vehicle does not move. Go back into the editor and change the empty vehicle to another kind of MRAP or any other type of vehicle, then restart the mission and observe that the vehicle now moves to its waypoint.

Try also keeping the Hunter, but shifting its position slightly on the road. Sometimes this enables it to move.

Additional Information

I haven't tested all vehicle types, but the problem can be reproduced reliably in this situation using the Hunter.

For convenience, the mission uses an empty Hunter with an AI being assigned to drive it, but the same results can be observed using a manned Hunter.

Video courtesy of DasAttorney:

Event Timeline

JoeOBrien edited Additional Information. (Show Details)
JoeOBrien set Category to AI Pathfinding / Motion.
JoeOBrien set Reproducibility to Sometimes.
JoeOBrien set Severity to None.
JoeOBrien set Resolution to Open.
JoeOBrien set Legacy ID to 1721595678.May 8 2016, 12:05 PM
Adam added a comment.May 15 2015, 1:20 PM

Hello, i'm unable to reproduce the issue. Could you please provide more info? Thanks!

Lex added a subscriber: Lex.May 8 2016, 12:05 PM
Lex added a comment.May 15 2015, 2:24 PM

This problem has the general components

Adam - restart the mission a few times and the Hunter will sometimes not move.

Adam added a comment.May 15 2015, 2:58 PM

Restarted about 15 times. Still no luck reproducing it. Are you running mods by any chance?

No mods. I can consistently reproduce the issue using that mission. Latest Dev version 130759. Vanilla + all DLCs. I'll see if anyone else can repro it.

Video added (by someone else who was able to repro it)

Hello, I just tried the attached mission. I played it six times and twice the Hunter failed to move. I used "restart" from the menu each time as opposed to going back to the editor and then restarting it if that helps at all.

I'd appreciate it if someone could have another try at reproducing this, because I played my test mission recently and like Adam, I couldn't repro the problem even after restarting the mission several times. But then I loaded another mission and then back to my test, and the Hunter would not move.

(Not to mention that others have confirmed the issue).

Lex added a comment.Jun 7 2015, 2:11 PM

It not an error of mission. AI always surprises not with predictable behavior. One of many examples, AI is fixated on a transit choice to a point. If I did not sit the passenger, I would not understand that happened to him. It for hours could twist a wheel there, and I waited for it)))

I have attach a folder called "hunter_wont_drive.Altis".
For me the vehicle always stops at the slope (100%).
Please let me know if your vehicle doesn't stop!

productVersion // ["Arma 3","Arma3",148,131645,"Stable",false]

Yes, the hunter stops on the slope in front of the player despite having a scripted move command to a location about 2km away. It still doesn't move if given a new destination via the debug console.

Also, just pointing out again that the behaviour of the hunter in my original repro is still consistent with my report and also the behaviour shown in the linked video. In that particular scenario, the hunter does not move to its waypoint, but does slowly slide along the ground with its wheels turned sharply to one side as if the vehicle is trying to go one way and the driver another. After a few seconds, the driver wins and the hunter goes on its way.

In other scenarios the hunter just sits motionless for minutes at a time, then may or may not move. I've seen it happen on dirt roads and paved roads, but dirt roads seem to be the main culprit. I can consistently reproduce the issue by simply moving a hunter to any dirt road. Sometimes it follows the waypoint, but if you shift the hunter's position slightly on the road, this can cause it to get stuck.

I tried ticket authors repro mission and can still reproduce the behavior almost every time. Front wheel turned sharply right, vehicle slowly drifting/rotating left. Can also add it make no different if SR_Hunter is a "B_MRAP_01_F" instead of a "B_Soldier_F" and placed on the same spot as the empty vehicle.

productVersion // ["Arma 3","Arma3",150,131969,"Stable",false]

Could this be related to mass somehow? Whenever a hunter is stuck, setting its mass to 2000 lets it move. You can see the suspension ease off as if there was another MRAP sitting on top of it. I guess decreasing the vehicle's mass would do that anyway, and maybe this is just a coincidental solution rather than proof of the root problem, but I'm throwing it out there.