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Ground sinking feature causing problems with player hitboxes, also creates problems with walls and objects
Closed, ResolvedPublic


Arma 3 bug that was recently discovered. This bug is from the feature that makes you sink into the ground in Arma 3. The player shrinks but the hitboxes do not shrink with the player. This feature also causes problems when people are shooting over walls. People are able to shoot over walls/rocks/objects etc. but not be seen by the player they are shooting at because they are sunken into the ground. video explaining how this bug works. Also shows the problem when people are behind walls. I also think this is the reason people can lean corners and not be seen when shooting not 100% on that but it's a theory I have.


Won't Fix
Operating System
Windows 7
Operating System Version
64 bit
Steps To Reproduce

Place target into grass, he will sink into the ground when the player is farther away. Hitbox seems to remain in the same place. Causes problems with the player not being able to see people that are shooting at him aswell. On walls you can peak over, also I believe it causes problems when people are leaning corners.

Event Timeline

aimpr added a subscriber: aimpr.Aug 19 2016, 4:19 AM

replace shrinks with sinks :)

Please fix ASAP!

This bug is pretty damn annoying to say the least, if fixed it would make the game much more fair and playable for everyone.

VissGames updated the task description. (Show Details)Aug 19 2016, 4:38 AM

This is gamebreaking, please fix!

razazel changed the task status from New to Reviewed.Aug 19 2016, 9:54 AM
razazel claimed this task.

This needs a fix now! Please show your community that much respect and dont let us wait 3 months before you fix it! Thank you.

hazd added a subscriber: hazd.Aug 19 2016, 11:30 AM

This is game breaking and needs fixing as soon as possible.

Boute added a subscriber: Boute.Aug 19 2016, 11:59 AM
RAMR_ added a subscriber: RAMR_.Aug 19 2016, 12:11 PM

Please prioritize a fix for this as soon as you possibly can. This can be exploited by players so easily.

Would be nice to have it fixed in 1.64

Rudged added a subscriber: Rudged.Aug 19 2016, 12:36 PM

I experienced that many times, "Player vs Walls" is nice for bricklayers but I wanna play vs Players. It would be nice if you can fix this soon because it totally ruin the experience for all the PvP mods and even solo missions.

HayZ added a subscriber: HayZ.EditedAug 19 2016, 12:38 PM

Game breaking bug that needs attending to right away.
Not quite sure how this was missed when adding this feature to be honest...

f0xteR added a subscriber: f0xteR.Aug 19 2016, 3:19 PM

Yep Game breaking Bug... hope it will get fixed soon

This is a major problem and needs to be fixed if we want competitive Arma to keep growing.
Why not just remove the sinking in completely?

DiBBz added a subscriber: DiBBz.Aug 19 2016, 7:11 PM

yeah i was about to say.. this is not a minor problem.. this is quite a severe problem that needs to be dealt with ASAP.

because arma is so PvP orientated as well as PvE. it affects both players and AI. so if you cant effectively kill the person you are trying to shoot in 1 shot them it becomes a real problem for the entire game itselfs. weather it being strategy or tactics etc

Let's not blow this out of proportion. Yes this is a big issue, but it's by no means "game breaking." Game breaking would be if you were to zoom in on someone's head and your game instantly crashes. I also don't think BI appreciates you guys telling them in what time frame things should be fixed.

Having said that, here are two missions based on the situations used in the video to display the issue with icons as visual aids.

First mission is GrassCoverRunway, showing two soldiers down the runway with icons marking their head and neck hit points. There is also a soldier just to your right to show what the hit point positions are like at a close distance.

As described in the video, you can see the soldier "in grass cover" has his hitpoints higher than what the model shows.

While the soldier on the right has his hit points lined up correctly with the model.

Second mission is GrassCoverWall, showing the same situation you described in the video, but this time with icons for hit points and the position of the unit's eyes. There is also a line being drawn between the eye positions of the two soldiers, but it's a little hard to see in first person.

Looking at the soldier behind the wall you can barely see his head because he is "in grass cover", but in reality his hit points are above the wall. If you were to shoot where the hit point icons are located you would hit and kill the soldier.

From the other perspective you can cleanly see and shoot the head and neck of the elevated soldier.

I agree with Pennyworth on this. It's a major issue, but it's definitely not game breaking. (It might be game-mode breaking though, depending on what one plays).

I understand that the sinking is something that cannot be easily removed as it's quite complex and we all know it has been part of the game for a very long time. I don't know if either the hitbox issue has simply been there all the time (without anyone noticing it - I doubt that to be honest) or if it got in with one of the recent updates. Thinking of the RoadToApex related changes (visual upgrade, LOD changes, ...).

Would be nice if you guys could keep us updated on that, as it seems to affect a lot of players in various communities ;)

miklide added a subscriber: miklide.EditedAug 20 2016, 6:45 AM

Rust reminding everyone about this ticket

lev added a subscriber: lev.Aug 20 2016, 10:35 AM

You should probably update the severity of the bug to something higher. I wouldn't call this minor as it severely negatively affects the experience of multiplayer pvp and I suspect a lot of coop games as well where it seems that you just could not hit the AI for some reason or how AI just seems to spot you without you being able to see them.

Schnucki added a subscriber: Schnucki.EditedAug 21 2016, 2:55 PM

just did some testing how the grass render distance affects this issue.
used command:

setTerrainGrid X;

with X = 25 (according to "Standard"):

with X = 3.125 (according to "Ultra"):

with X = 50 (acoording to "Low" / no Grass):

As you can see the sinking feature can be affected by this value in two ways:

  1. setting TerrainGrid to low values for higher grass render distances to trigger the feature only in higher distance. downsides are the effect on fps and limitation by the game (about 150m).
  2. setting TerrainGrid to 50 what means that there is no grass at all and disables the sinking feature.

maybe devs of mods and missions can think about these workarounds.

edit: btw tested on Arma 3 v.1.58 due to SteamOS + Linux Version

maybe Razazel could merge this ticket with mine T119989

Is there a reason why the alternate idea in this post Isn't feasible?

The short term fix that I can figure out would look worse but fix the hit boxes is to disable the model sinking ( because both players can see all of each other at distance there is no balance issue)

Obviously the longer term fix is to not sink the model and obscure grass covered parts in some other way than sinking models.

I guess this explains the "headglitch" problem that bugs so much (Battlefield 4 had their headglitch problem fixed some time ago).

Any news? Any info at all? Is this gonna get fixed? Nothing about it in the latest patch notes. Can we get some info please!

I cannot belive that this is marked as normal.

Anatanokami added a comment.EditedSep 22 2016, 7:26 PM

@FaustoCoppii It has been mentioned here - It was also explained why this won't be fixed any time soon (if ever).

While the issue itself has been present for quite some time (even in previous titles), it is not something we can easily fix due to technical limitations

Japo32 added a subscriber: Japo32.Sep 26 2016, 4:10 PM

I think it can be fixed adding a transparent geometry around the IA (or player) from ground to knees or so... (depends on grass high) when they are among grass. So that transparent geometry make see through the IA geometry the ground behind (and simulates the same cut vision.
That way there is no need to shrink the IA or whatever and the hit geometry is where it has to.

Just add an option to enable/disable the feature on servers first of all.
Taking cover in grass isn't a thing in many gamemodes. Admins would have the choice to offer it with the inconveniences or disable it for having matching hitboxes.

lasagne_ added a subscriber: lasagne_.EditedOct 4 2016, 4:24 PM

While this is considered a problem in PvP, perhaps it may be worth identifying how this affects PvAI? I presume that the AI will 'look' from where the hitboxes are supposed to be, rather than where the model appears. Additionally, are we certain that the AI can't "see through" the grass anyway?
I think that, at least until a proper fix can be made, model-sinking should be disabled (maybe leave an option for it?), as it makes shooting at nearly all ranges very inaccurate.

+1 I always used to think soldiers appearing to sink through the terrain was a rendering issue

I do think it's potentially game breaking in certain cases, and I think this hitbox shifting has frustrated many of us for many years - but I think those unaware of the issue just thought we were bad at aiming or bullet drop compensation (at least, I did). I can understand why some communities have disabled it in PvP.

There's also a question of what AI aim at - the hitbox, or the model?

As for solutions, I think it should be along the lines of:

  1. Try implementing what @john681611 linked to, and render the alpha layer of grass 2m around a unit in the distance, so that the grass is native to the place and all viewing angles are covered (though honestly it's local to the viewing client so maybe one direction is enough)
  1. If (1) is successful then there's no need to sink the player model
  1. Perhaps considering revising the grass rendering process and making it more efficient and allowing the engine to render say 100m of grass without much of a performance hit (ideally no worse than the current default)

(3) is probably not required if (1) and (2) can be done, but would be really nice. It shouldn't be impossible either, games like Far Cry manage it well enough - although the tech involved is different, of course.

Would be really good if BI could fix this soon (TM), because it does cause game play issues all the time - but I think most of us wouldn't want to disable grass.

barccy added a subscriber: barccy.Jun 22 2020, 11:15 PM

Just get rid of the grass.
OFPR / ARMA CWA was and remains fun though still challenging to play without the frustration, but with lower system requirements and smaller file sizes.
Grass issues also cause frustration in similar games like 'Squad'.
There are multiple mods and addons dedicated to reducing or removing the grass on A3 terrains.

dedmen removed razazel as the assignee of this task.Nov 3 2020, 11:39 PM
dedmen closed this task as Resolved.
dedmen changed Resolution from Open to Won't Fix.
dedmen added a subscriber: razazel.
dedmen added a subscriber: dedmen.

Won't be fixed.