Dwarf Fortress Bug Tracker - Dwarf Fortress
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0005945Dwarf FortressDwarf Mode -- Combatpublic2012-05-23 21:362014-08-24 09:42
0005945: Thrown/dropped clothes do more damage than blocks
I'd set up an automated dump hole to drop body parts, remains, unusable corpses, etc. into a self-locking hole, in case a necromancer swung by for a visit. Basically just a garbage zone on top of a hatch over a hole linked to a pressure plate in a walkway.

Apparently one of my farmers managed to find his way into the hole (probably trap-doored in) and some rat remains fell on his head, caving in his skull and killing him.

I have had other injuries caused by falling objects, but the worst I've seen so far is bruising from logs and stone blocks. This is not only the first serious injury I have witnessed from falling objects, it is also one of the weirdest I could imagine: rat remains weigh 1 lb (dwarfkilo?) while blocks and logs weigh several whatever-the-units-are each. Especially given that it only fell a couple feet, a rat should not be able to cave in a skull... especially one belonging to a the notoriously thick-headed dwarven race.
Drop stuff on dwarves.
Save at http://dffd.wimbli.com/file.php?id=6379 [^] showing the dump setup (just outside the main hall) and containing the combat report showing the fatal injury.

I imagine this might be related to 0001600 if perhaps the collision system accounts only for weight and not for velocity, or some such.

I also realize that 0005907 is on the same topic, but since that report doesn't address the relevant cause/effect imbalance, I felt that this issue deserved its own report.
No tags attached.
related to 0005907resolved Toady One Deconstruction results in falling blocks injuring dwarves 
Issue History
2012-05-23 21:36DrazinonondaNew Issue
2012-05-24 10:02FootkerchiefRelationship addedrelated to 0005907
2012-05-24 12:28QuietustNote Added: 0022709
2012-06-19 14:56TelarinNote Added: 0023060
2012-06-19 14:56TelarinIssue Monitored: Telarin
2012-06-28 15:54kwielandNote Added: 0023123
2012-06-29 08:24kwielandNote Edited: 0023123bug_revision_view_page.php?bugnote_id=0023123#r8638
2012-06-29 12:24sandwichNote Added: 0023126
2012-07-01 21:36ab9rfNote Added: 0023137
2012-07-02 06:27ab9rfNote Edited: 0023137bug_revision_view_page.php?bugnote_id=0023137#r8642
2012-07-02 17:18ab9rfIssue Monitored: ab9rf
2012-07-08 07:40uggiNote Added: 0023182
2012-07-08 13:15JasonMelNote Added: 0023184
2012-07-08 15:50sandwichNote Added: 0023187
2013-01-29 17:07arclanceIssue Monitored: arclance
2014-01-26 10:24FootkerchiefSummaryCollision damage can be very exaggerated. => Small objects do excessive damage when dropped/thrown
2014-08-20 11:49ButtonIssue Monitored: Button
2014-08-22 14:49BenLubarIssue Monitored: BenLubar
2014-08-22 16:144maskwolfIssue Monitored: 4maskwolf
2014-08-23 21:30UristDaVinciNote Added: 0029557
2014-08-24 07:11FootkerchiefSummarySmall objects do excessive damage when dropped/thrown => Falling clothes do more damage than falling blocks
2014-08-24 07:12FootkerchiefSummaryFalling clothes do more damage than falling blocks => Thrown/dropped clothes do more damage than blocks
2014-08-24 07:12FootkerchiefAssigned To => Footkerchief
2014-08-24 07:12FootkerchiefStatusnew => confirmed
2014-08-24 09:42smjjamesNote Added: 0029572
2018-04-16 10:23HuntthetrollIssue Monitored: Huntthetroll

2012-05-24 12:28   
Side note: 1Γ is equal to 1 kilogram - if that's how much the rat remains weighed, then that must've been one huge rat, since normal rats are rarely more than 500g.
2012-06-19 14:56   
I see this a lot, often with old clothing being dumped. An example I am looking at right now:

The x({alpaca wool dress)}x strikes The Dwarven Child in the head, brusing the muscle, jamming the skull through the brain and tearing the brain!

Child was killed by a falling dress, that does seem a bit outlandish. And this is not a one-off event either, these falling clothes are downright deadly on a regular basis!
2012-06-28 15:54   
(edited on: 2012-06-29 08:24)
I have also seen light weight clothing items seriously injure dwarfs.

2012-06-29 12:24   
i had a xcave spider silk sockx that jammed child skull through his brain , after falling 4 z levels. the child was legendary bone carver and he was 16 years old.
2012-07-01 21:36   
(edited on: 2012-07-02 06:27)
I just had a dwarf take damage (bruising) from having a spiderweb fall on him from one level above.

Additional information regarding silk web damage:

The giant cave spider silk web strikes The Dwarven Child in the left upper arm, jamming the bone through the left shoulder's muscle and shattering the left shoulder's bone!
The giant cave spider silk web strikes The Dwarven Child in the head, bruising the muscle and tearing apart the upper spine's nervous tissue through the -alpaca wool hood-!

Essentially a fatal blow from a spider silk web that fell one z-level in my silk farm. I have lots and lots of dwarfs with less severe injuries.

2012-07-08 07:40   
I had an adventurer dwarf with superdwarven attributes and legendary skills killed by a falling raven corpse (well, a half of the corpse). The raven was prone and somehow stuck mid-air one z-level above me. I was standing directly below it and severed the raven in half with my pick. One half of it landed next to me, the other half caved my skull in. I had no helmet, only a pig tail fiber cap. In real life, an average common raven weights about 1,2 - 1,3 kg, and only the half of it hit me. This was in 0.34.11.
2012-07-08 13:15   
At the risk of stating the obvious, the problem with all of these examples is not necessarily either unrealistic velocity or weight (mass), but a lack of any representation of air resistance.
2012-07-08 15:50   
i had a iron anvil that fell on my military comander , it only shattered his skull through =copper cap= . i guess it was pure luck.
2014-08-23 21:30   
There are a few things that contribute to this bug:

1. The original bug reports were from 2012 (0.34.11), where skulls were thinner than in the recent 0.40.xx versions.

2. Falling ITEMS in the post-minecart versions use the new velocities, and are capable of flying in a parabola. To convert the new velocity to the old velocity used in the combat code for projectiles, the game appears to divide the new velocity by 300:

z-levels fallen/new velocity/old velocity
1 34300 114
2 53900 180
3 63700 212
4 78400 261
5 88200 294
6 93100 310
7 102900 343
8 107800 359

In comparison (all units in old velocities), 0.34.11 crossbows shot bolts at 1000, and 0.40.08 crossbows shoot bolts at 30-45 for various metal bolts, and a max of 200 for lightweight wood bolts. Melee weapon users tend to swing in the range of 10-30 velocity. The consolation is that the skill required to dodge falling items is very low.

3. Items that have ATTACK tokens such as weapons, ammo, trap components, and some tools use that data when falling on someone. Items that don't have that data calculate their contact areas as VOLUME ^ 2/3. This leads small items like rat remains or socks to have tiny contact areas, concentrating the force of impact similar to the bolt or whip problems. It appears that a wool dress has a higher (more dangerous) momentum:contact_area ratio than a stone block.

4. There does appear to be an existing check in the game such that blunt items with a small volume and IMPACT_YIELD will deflect off heavy armor layers regardless of how fast the item is moving, but this is balanced such that you need to wear metal armor to be protected from falling socks.

5. As mentioned above, air drag is not a DF concept. 0.40.xx made liquids and powders do no damage on impact, however the game does not yet distinguish between flexible socks and rigid anvils.

Recommendations: Change the conversion rate between old velocities and new velocities. Weaken the combat capabilities of items with [SOFT_MAT] or [SOFT].
2014-08-24 09:42   
Yeah, my adventurer got his head smashed in by a peasant skeleton whacking him with a coat. I can see a heavy coat stunning you or knocking you over, but that coat must have been made of lead.