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Strange damage distribution
Assigned, NormalPublic


Compared to the previous games, ARMA 3 seems to be more deadly. I attached a <i>handleDamage</i> to a unit to try to see why. I discovered that there is something weird with the way damage is distributed to individual hitpoint components.

It appears to me the engine uses a weighting system to determine which hitpoints were affected by a received hit - the closer a hitpoint is to the hit, the more damage it receives. While I do not believe this can realistically represent injury that is not the point of this ticket.

The problem I discovered is that either the weight calculation or the hitpoint definition on the models is incorrect. This is very clear for hits that land in the <i>general</i> vicinity of the head. It seems that anything above the abdomen results in more damage being dealt to the head (<i>"head_hit"</i>) than to the torso (<i>"body"</i>). From the chest area upwards, the head damage actually becomes equal to that of a direct headshot, making even a pistol shot a one-hit kill.

Since a picture is worth a thousand words I created a short video which describes the problem (make sure you have annotations enabled):

A more detailed tabulation of values for individual hits can be found in the attached picture (<i>damage_distribution.png</i>). {F19287} {F19288} {F19289}


Legacy ID
Health System
Steps To Reproduce
  1. Open the attached mission <i></i> in editor and preview.
  2. Shoot the person in front of you with the rifle and observe the damage values.
  3. Switch to pistol and shoot the person some more. Focus on the chest area and note that the <i>head_hit</i> values are >1 (instant death)
  4. To ensure the problem is not caused by the handleDamage EH used to display the damage abort mission and remove the execVM part from the unit's init line
  5. Preview the mission again
  6. Confirm that you can kill the unit with a single pistol hit to the chest
Additional Information

The issue is present in both Stable 0.56.104778 and Development 0.55.104711 versions.

Event Timeline

Deadfast edited Steps To Reproduce. (Show Details)May 5 2013, 10:15 PM
Deadfast edited Additional Information. (Show Details)
Deadfast set Category to Health System.
Deadfast set Reproducibility to Always.
Deadfast set Severity to Minor.
Deadfast set Resolution to Open.
Deadfast set Legacy ID to 2257116204.May 7 2016, 1:59 PM

Also, Handledamage doesn't even work at player. You still get killed normally. BIS should fix it.

epoch71 added a subscriber: epoch71.May 7 2016, 1:59 PM

Needs looking at for sure. Submitted 5 days ago and not yet assigned - I'd have thought a functioning damage system would be a fundamental feature ....?

Loki added a subscriber: Loki.May 7 2016, 1:59 PM
Loki added a comment.May 11 2013, 3:53 AM

I don't know if I understand right. But a hit into the chest makes you fast bleeding out. Not sure.

On the pic I can't see that a shoot into hearth differs from a normal body hit. Naturally I would think that bodyparts and critical zones are not the same.

hm .. left side differs extremely from the right. Could be that lung/heart shoot would count as a headshoot.

From personal testing I've noticed that when using civi models they will always die from a single pistol shot to the head from point blank range. Helmetless Blu/Opfor always require two shots to the head. I assume it is because different damage values are assigned based of different uniforms along with other equipment.

Basically what I'm getting at is that your video shows damage output from one type of weapon against a single type of load out and your response features hyperbole.

<b>@Loki</b>: A hit in the chest applies more damage to your head than to your body. Realistically, a hit to the center mass would be more deadly than a hit to the stomach, but looking at the sample character model - unless it was changed - this isn't intentional, the fact that shooting your upper arm causes head damage suggests that as well. And even if it were intentional, calling your chest a head is not the way to go. There should be a separate hit zone for it.

<b>@taunkatruck</b>: Your testing is flawed then, it takes one shot to the head no matter what: You should check you don't have extended armor enabled. Just because I only showed myself testing it with one weapon and one unit doesn't mean I didn't test it with others, I did. The results were exactly the same, no matter what gear the unit was wearing. That's actually how I discovered this, I wanted to make a unit wearing a bulletproof vest more resistant to body damage. Cue my surprise when they all died of headshots. If you don't believe me, the mission I tested this with is attached, you can try it yourself with different units and gear.

Loki added a comment.May 11 2013, 3:47 PM

I looked into and it is really irritating that a shoot in the arm technically effects other bodyparts no matter in which dimension. If i shoot them normal several times into the leg they die. That could be the wanted effect at the moment or it is simply the result of the used collidingsystem. If I only shoot to legs there is only blood on the legs. In this case it seems to work fine. But sometimes bulletcollide fails like in the video.

I think men can take a lot of shoots into most noncritical bodyparts without dieing by that. It only fasten the bleeding out.

OK sometimes when I shoot the shoulder blood goes only to head. Hopefull that all the men didn't died for nothing.

After testing this out it explains why during testing of certain things when I have shot people they have died as if they were shot in the head.

Definitely needs looking at and preferably changed to at minimum head shots are the only ones to cause head damage, would be better to have areas kept to same hit area with a faster bleed out for more wounds.

Or there will be Codie meme soon: "I recieved shot to the legs and my head is bleeding badly..." ;)

I revisited this in 0.77.109936. The issue still exists but it different - where previously shooting somebody in the chest produced damage to other parts and lethal head damage, shooting a person in the chest now produces very little component damage (<0.1 even with a rifle). This leads to two problems:

  1. It takes 4 pistol shots to kill a person when shooting him in the chest but only 3 when shooting him in the abdomen
  2. Blood textures will not be applied when shooting a person in the chest as opposed to anywhere else

Hitting high chest/neck area results in a "hand_l" hit...

Helari added a subscriber: Helari.May 7 2016, 1:59 PM

I don't get how distributing damage to areas that aren't actually hit is a good idea. Please fix.

Re-tested in 1.05.111758, the issue described in my previous comment is still present - chest isn't considered to be a part of body.

Re-tested in 1.19.124337, huge improvement can be observed.

I did notice there is still a (now quite small) zone between the head and the chest which doesn't seem to be be correctly associated to the hitpoints correctly and shooting it produces little component damage. See the attached picture <i>head_body_gap.png</i>.