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Swimming phyics of east german apcs not working correctly.
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The handling of the BMP, BRDM in water seems very wonky, there a huge amount of drift and a very wide turn radius. Going from water to land is also an issue because the vehicle will turn itself almost completely around once the tracks/wheel contact the ground. Vehicles controlled by the AI will get stuck once in water and unable to move forward or turn.


Operating System
Windows 10 x64
Game Physics
Steps To Reproduce

Drive a BMP or BRDM out into a body of water, then use a move command to get the AI to drive back to land.

Additional Information

Tested against vanilla vehicles that are amphibious, which seem to work fine for both the player and AI. I'm also using ARMA 3 dev branch.

Event Timeline

Same issue with the M113, and to a lesser extent the Fuchs. Vanilla vehicles do show a similar behaviour, but the difference is that they have a tighter turn radius which makes it more controllable. Note that boats seem to handle very differently to amphibious vehicles.

I made some videos:

Here's some videos for better reference concerning the AI handling. I suppose after testing multiple vehicles together, the wheeled ones do fair better than the BMP, which seems like the only one that gets stuck. The M-113 might be the same as well. Maybe because of the tracks? I also tested the RHS BMPs to see if maybe its an ARMA problem, but they seem mostly fine.
Vanilla Control
GM Vehicles

GalComT claimed this task.Jun 26 2019, 12:24 PM
GalComT changed the task status from New to Confirmed Internally.
GalComT triaged this task as High priority.Jun 26 2019, 12:31 PM
BIS_Dantes changed the task status from Confirmed Internally to New.Dec 11 2019, 12:22 PM
BIS_Dantes raised the priority of this task from High to Urgent.

Well, I am mostly unable to control this vehicles in the water. (Just forward or backward, turning is almost impossible). Same with AI driver.

Same kind of issues with PT-76. It seems that if you stop vehicle when it just enters water and hatches are opened, it many times get stuck and won't move at all or moving very slowly. Same can happend when entering from water to land and stopping on point when hatches are closing. Maybe that is issue that vehicle cannot move on land with hatches open and cannot move on water with hatches closed and now vehicle is half in water and half on land and got stuck? Seems to work fine when entering water or land with speed and not stopping on water line.

GalComT closed this task as Resolved.Jun 20 2020, 10:56 AM

BTR, BRDM, OT64, and TPz1 have been addressed, swimming PX of Tracked vehicles will be handled in as that's a different issue