Dwarf Fortress Bug Tracker - Dwarf Fortress
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IDProjectCategoryView StatusDate SubmittedLast Update
0000833Dwarf FortressProjectilespublic2010-04-08 15:402012-02-22 00:36
ReporterMilaha 
Assigned ToFootkerchief 
PrioritynormalSeverityminorReproducibilityalways
StatusresolvedResolutionno change required 
PlatformOSWindows 7OS Version
Product Version0.31.01 
Target VersionFixed in Version 
Summary0000833: Adamantine bolts do less damage, bolts ineffective in general
DescriptionAdamantine Bolts will at most dent creatures and bruise skin. Other forms of bolts fired from the same weapon cause significantly more damage (generally tearing muscle and bruising layer underneath).

A guess off the top of my head would be that the problem lies in the weight of the bolt, since other Adamantine weapons are highly effective.
Steps To ReproduceEasily tested with bowdwarf equipped with Adamantine bolts in arena mode.
Additional Information
TagsNo tags attached.
Relationships
parent of 0001362resolved Dwarfu crossbows don't do enough damage to camels 
has duplicate 0002041resolved Footkerchief Hunters level incredibly fast, mainly because animals die too slow 
has duplicate 0002774resolved Footkerchief Crossbows ineffective against trained armor users (goblins) 
related to 0000033resolved Toady One Bronze colossus, skeletal creatures, fleshballs, and others are impossible to kill 
Attached Files
Issue History
Date ModifiedUsernameFieldChange
2010-04-08 15:40MilahaNew Issue
2010-04-08 15:45thvazNote Added: 0002180
2010-04-08 15:50G-FlexNote Added: 0002183
2010-04-08 17:41MilahaNote Added: 0002203
2010-04-08 17:58MilahaNote Edited: 0002203bug_revision_view_page.php?bugnote_id=0002203#r667
2010-04-08 17:59MilahaIssue Monitored: Milaha
2010-04-08 18:06MilahaNote Edited: 0002203bug_revision_view_page.php?bugnote_id=0002203#r668
2010-04-08 18:17SirPenguinNote Added: 0002207
2010-04-08 18:20MilahaNote Edited: 0002203bug_revision_view_page.php?bugnote_id=0002203#r669
2010-04-08 18:22MilahaNote Edited: 0002203bug_revision_view_page.php?bugnote_id=0002203#r670
2010-04-08 18:24GreyhawkNote Added: 0002208
2010-04-08 18:24FootkerchiefNote Added: 0002209
2010-04-08 18:31MilahaNote Added: 0002212
2010-04-08 18:34MilahaNote Edited: 0002212bug_revision_view_page.php?bugnote_id=0002212#r674
2010-04-08 18:40FootkerchiefNote Deleted: 0002209
2010-04-08 18:41GreyhawkNote Added: 0002215
2010-04-08 18:48MilahaNote Edited: 0002212bug_revision_view_page.php?bugnote_id=0002212#r677
2010-04-08 18:50MilahaNote Added: 0002217
2010-04-08 18:54MilahaNote Edited: 0002217bug_revision_view_page.php?bugnote_id=0002217#r679
2010-04-08 18:57MilahaNote Edited: 0002217bug_revision_view_page.php?bugnote_id=0002217#r680
2010-04-08 19:04GreyhawkNote Added: 0002222
2010-04-08 19:21MilahaNote Added: 0002224
2010-04-08 19:21MilahaNote Edited: 0002224bug_revision_view_page.php?bugnote_id=0002224#r682
2010-04-20 09:46FootkerchiefSummaryAdamantine Bolts do less damage => Adamantine bolts do less damage, bolts ineffective in general
2010-04-20 09:46FootkerchiefRelationship addedparent of 0001262
2010-04-20 09:46FootkerchiefRelationship deletedparent of 0001262
2010-04-20 09:46FootkerchiefRelationship addedparent of 0001362
2010-04-20 10:22quatchNote Added: 0004348
2010-04-20 11:07darkfredNote Added: 0004355
2010-04-20 11:27darkfredNote Edited: 0004355bug_revision_view_page.php?bugnote_id=0004355#r1474
2010-04-20 11:30darkfredIssue Monitored: darkfred
2010-04-20 11:43darkfredNote Added: 0004363
2010-04-20 11:47darkfredNote Edited: 0004363bug_revision_view_page.php?bugnote_id=0004363#r1476
2010-04-20 12:04SquirrelloidNote Added: 0004366
2010-04-20 12:37NimrodNote Added: 0004372
2010-07-05 16:39FootkerchiefRelationship addedchild of 0000033
2010-07-15 08:38FootkerchiefRelationship addedhas duplicate 0002041
2010-07-15 08:40FootkerchiefIssue Monitored: Toady One
2010-07-15 08:40FootkerchiefNote Added: 0010354
2010-07-20 15:09Lord ByteNote Added: 0010747
2010-07-20 15:17FootkerchiefRelationship addedhas duplicate 0002774
2010-07-21 07:08Lord ByteNote Added: 0010777
2010-07-21 09:21ProfligateIssue Monitored: Profligate
2010-07-21 10:52OzoneGrifNote Added: 0010786
2010-07-21 12:08Hieronymous AlloyIssue Monitored: Hieronymous Alloy
2010-07-22 04:05Rafal99Note Added: 0010807
2010-07-22 04:08Rafal99Issue Monitored: Rafal99
2010-07-22 09:03Lord ByteNote Added: 0010823
2010-07-22 09:06Lord ByteNote Edited: 0010823bug_revision_view_page.php?bugnote_id=0010823#r4194
2010-07-25 14:43FootkerchiefRelationship replacedrelated to 0000033
2011-04-21 08:53KogutTag Attached: CLOSE THIS
2011-04-23 04:46KogutIssue Monitored: Kogut
2011-05-08 14:26Logical2uTag Detached: CLOSE THIS
2011-05-08 14:27Logical2uNote Added: 0017662
2011-05-08 14:27Logical2uTag Attached: AWAITING UPDATE
2011-10-14 05:49KogutNote Added: 0018810
2011-10-14 05:50KogutNote Edited: 0018810bug_revision_view_page.php?bugnote_id=0018810#r7062
2011-10-14 05:52KogutNote Deleted: 0018810
2012-02-20 18:54FootkerchiefNote Added: 0020311
2012-02-20 18:54FootkerchiefStatusnew => resolved
2012-02-20 18:54FootkerchiefResolutionopen => no change required
2012-02-20 18:54FootkerchiefAssigned To => Footkerchief
2012-02-20 18:54FootkerchiefTag Detached: AWAITING UPDATE
2012-02-21 10:56Rafal99Issue End Monitor: Rafal99
2012-02-22 00:36KogutIssue End Monitor: Kogut

Notes
(0002180)
thvaz   
2010-04-08 15:45   
Makes sense in fact. I want to make adamantine-pointed lead bolts!
(0002183)
G-Flex   
2010-04-08 15:50   
Yeah, this is probably not a bug, since adamantine has a density of 0.2g/cm^2, which is less than most cork, which is the only thing I could find that seems remotely comparable. Some woods are less dense, but most are much more dense, and it's not like you should be making arrows and bolts out of balsa anyway.

I can see adamantine bolts being good once we get multiple-component items in. Say, a steel shaft with an adamantine head.
(0002203)
Milaha   
2010-04-08 17:41   
(edited on: 2010-04-08 18:22)
Well, I would consider it a bug, due to the fact that IRL this actually has a much lesser effect than you would expect afaik, a lower weight simply causes a higher velocity conveyed by the firing weapon, and maintains a similar kinetic energy. Sure it plays some role (especially at extreme values) but the problem here is more likely that the weapon fires the projectile at a set velocity, rather than realistically simulating the velocity based on the weapon material, construction, and projectile weight.

A "quick fix" would be to force all projectiles to be a set weight, to account for the set velocity, as obviously a complete overhaul of the projectile weapon system is not something that we can expect any time soon (if ever).

To put it in math terms

E = M * A

E is provided by drawing the weapon, and does not change based on the projectile loaded in, thus as Mass goes down, Acceleration goes up. This process is reversed on impact, and energy conveyed remains about the same.

EDIT: Checking RAWs, it does appear this equation is properly modeled, however the max velocity value may be (way) too low. (comments say it is set based on how fast the string could possibly go, which is crazy fast)

EDIT2: Further testing has shown that the max velocity was the limiting factor with all ammo (by a LOT) thus we were looking at an accurate model, but with the E value cranked way too high, and the max velocity the string could go way too slow. Effectively making the mass of the projectile the largest factor in damage imparted. Altering only the max velocity, and leaving force the same bronze bolts are demolishing dragons. Simply tweaking these values to be a more accurate numbers should fix the issue.
(0002207)
SirPenguin   
2010-04-08 18:17   
I seem to recall some people saying that bolts in general seem to act more like a blunt object than a piercing one. Indeed, using your crossbow as a blunt object gives you 2x the penetration (4000 vs. 2000) than a bolt. That's...kinda weird.
(0002208)
Greyhawk   
2010-04-08 18:24   
My take on adamantine projectiles:

The force of resistance (from air and penetration) would be more due to higher velocity (less penetration, more impact).

The deceleration from that resistance force would be higher for a much less massive object (kinetic energy reduces faster over distance).

However, higher velocity would also mean a less arching trajectory (more accuracy, less reaction time for defense).

Also, skilled users can take advantage of the more direct aiming and can try to hit weaknesses (high critical rates for high skilled users)

Summary:
Optimal range is reduced.
Accuracy is increased.
Less response time for defense.
Highly-skilled users have an even better chance for critical hits.
Armor can't be pierced, but can still bruise.
Relies on critical hits for extreme damage.
(0002212)
Milaha   
2010-04-08 18:31   
(edited on: 2010-04-08 18:48)
SirPenguin: Looking at various values, it looks to me like higher penetration may be related to how far in the weapon goes rather than how easily it penetrates. Spears have a very high number (10k) and Daggers very low (1k). The earlier value (contact area) seems to be what would determine the ease of penetration. as both the dagger and spear have similar values in this regard.

Meanwhile the blunt weapons, or the cutting attack of a sword/axe have very high contact areas and high penetration values, to reflect a very deep cut that could possibly go clean through the body slicing the enemy in half, or in the case of blunt weapons (with even more force) breaking off a limb.

Greyhawk: The fact that even a bronze bolt achieves max velocity based on the maximum speed the string can travel reveals that the equation is all wrong. Yes, the things you stated would play a factor, but over the space of 10 squares there would be close to 0 air resistance playing a part. Before air resistance starts playing a part the engagement range would have to be MASSIVELY larger than what we are testing with, and in that case one would use a bow, not a crossbow and arc the projectile to cause a greater end velocity as you get gravity helping you provide a continued acceleration effect at the tail end of the flight.

EDIT: Going to throw on one more comment related to the physics involved... Crossbows were obscenly good at penetrating plate armor, due to the fact that the bolt was fired at an obscene rate of speed compared to a standard bow, and the projectile was solid metal. The E value was through the roof, as was the strength of the bolt(would not shatter on impact, reducing force, which a wooden arrow shaft would do if fired from a xbow against a hard surface). At the end of the day how you obtain E makes 0 difference (by mass or velocity) Higher E over smaller area = more penetration.

Take for example a modern firearm:

Anti-Armor = high E and high projectile integrity to increase piercing
Anti-personal = bit lower E and low low strength to increase impact and minimize piercing (a bullet that goes straight through causes much less damage than one that tears apart a huge chunk of flesh and stays in)

The mass of the object has very little to do with it, the anti-armor is likely made of steel, and the anti-personal is likely made of lead, both have a similar density.
(0002215)
Greyhawk   
2010-04-08 18:41   
"The fact that even a bronze bolt achieves max velocity based on the maximum speed the string can travel reveals that the equation is all wrong. Yes, the things you stated would play a factor, but over the space of 10 squares."

Isn't 10 squares like 60-80 feet or something? That's quite a bit of flight time. Even a baseball being thrown from a smaller distance has significant resistance. Otherwise you couldn't have curve balls.

"...gravity helping you provide a continued acceleration effect at the tail end of the flight."

It also decelerates when the projectile goes up, canceling out the effect.
(0002217)
Milaha   
2010-04-08 18:50   
(edited on: 2010-04-08 18:57)
A baseball is a whole different ball game. The forward facing surface area 10x as much, and the flight time to reach destination is also 10x as much. that puts you at about a factor of 100 compared to the impact it has on a bolt fired from a xbow.

"It also decelerates when the projectile goes up, canceling out the effect. "

Not quite, since air resistance is not linear in nature, but we wont get into that, suffice to say that the end velocity does end up being higher than a projectile fired straight would if you removed the force of gravity and only included air resistance.
(0002222)
Greyhawk   
2010-04-08 19:04   
http://www.crossbows-bolts.com/crossbow-bolts.php [^]

Actually a 16" or 22" bolt with 3 feathers looks to have a pretty close surface area compared to a MLB baseball (27.2 in^2).

http://www.thebeckoning.com/medieval/crossbow/cross_l_v_c.html [^]

138.7 fps was the speed of a bolt

http://www.efastball.com/baseball/pitching/grips/average-pitching-speed-by-age-group/ [^]

75-95 MPH for pitching (or 110-140 fps)
(0002224)
Milaha   
2010-04-08 19:21   
Only the forward facing surface area has any real effect on air resistance, not the whole thing... I am not even quite sure how to respond to your "same surface area" comment.

Also, I came up with a velocity of about 300 fps when it comes to xbows through a Google search, but I will admit my source was for a modern xbow (though you are using a modern baseball pitcher for your example, so meh).

Honestly, the fact that you stated the surface area was pretty close is reason enough for me to stop this conversation, it does not seem that you have an accurate grasp on the basic physics involved here.

Toady can decide on his own when he gets around to fixing it, because I think we both realize the current model is not accurate.
(0004348)
quatch   
2010-04-20 10:22   
Another point to consider on the weight of projectiles issue: (I am not an expert)

A less massive projectile (barring things like spin stability, which period weapons are unlikely to have) is more easily wobbled around by wind and such.

Example: throwing an iron feather: it goes where you want. Throwing a regular feather will see it waft around.

Perhaps this could help explain the lower damage of ineffectually light (by density, not size) weapons?
(0004355)
darkfred   
2010-04-20 11:07   
(edited on: 2010-04-20 11:27)
To do the same damage as a bronze bolt (at 9000kg/m3) an adamantine bolt would need to be traveling 21 times as fast. or around mach 4.

Obviously this doesn't even take into account air resistance.

Since arrow speed is based on the speed of the bowstring, the recovery speed of the spring rather than the weight of the projectile. I think even bruises are unrealistically high damage. These bolts should have no more effect than a feather or gust of wind.
(0004363)
darkfred   
2010-04-20 11:43   
(edited on: 2010-04-20 11:47)
Also mihala is not entirely correct. Arrows have significant lift resistance (both body and fletching) and turbulent drag in addition to frontal surface area resistance, they even have a small viscous resistance related to total surface area. This is why the bullet shape is used for high speed rifles even though a longer balanced cylinder would seem to have a greater penetration in a vacuum. Its a balancing act between velocity squared and air resistance. A teardrop shape is ideal, but unshootable.

Since as I mentioned above, adamantine arrows would need to be fired at speeds greater than high speed rifles, a cylinder is actually a terrible shape. From an air resistance perspective, it would lose most of it's energy staying straight.
(0004366)
Squirrelloid   
2010-04-20 12:04   
80' is pretty short range with a crossbow. Air resistance is not much of a factor over such short distances. I wouldn't imagine you'd see much effect of air resistance until somewhere in the 200'+ ballpark.
(0004372)
Nimrod   
2010-04-20 12:37   
god i love the smell of scientist in the morning (== darkfred is right)
(0010354)
Footkerchief   
2010-07-15 08:40   
Reminder sent to: Toady One

Hey Toady -- since bolts have been improved, this bug and 0001362 might be regarded as fixed.
(0010747)
Lord Byte   
2010-07-20 15:09   
Not so fast Footkerchief! Bolts are apparently completely useless against armored targets :( Static goblins get peppered with 2000 iron bolts in fortress mode and just stand there with not a scratch on them, EVERY shot having been deflected.
(0010777)
Lord Byte   
2010-07-21 07:08   
Further testing: Given enough time (and by decreasing the range a bit for more hits) they will eventually shoot off every unarmored extremity (toes, fingers, ears). The problem seems to be in armor vs bolts.
(0010786)
OzoneGrif   
2010-07-21 10:52   
Huh... in 31.10, I've seen many of my armored dwarves (bronze) killed by a squad of gobelin archers.

Or maybe arrows act differently than bolts ?
(0010807)
Rafal99   
2010-07-22 04:05   
I did a lot of testing in the arena today - dwarves shooting goblins with iron bolts.
Goblins in groups with copper, bronze, iron and steel armor, with and without silk clothing - 8 groups total, 10 goblins each.
The bolts were equally deadly to all groups. About 30 iron bolts were fired per each killed goblin, half of them missed, some were blocked, about 10 hits on average per goblin I think. Seems ok considering that crossbows are meant to be no longer insta-kill weapons. Also keep in mind that once a goblin gets hurt and goes prone, it is much harder to hit him with ranged weapons.

So balance seems ok to me.

@Lord Byte: Are you using 0.31.10? Is your fort copied from earlier version? If yes then have you updated item_weapon, item_ammo and material_template files IN YOUR SAVE FOLDER with the new ones from 0.31.10?
(0010823)
Lord Byte   
2010-07-22 09:03   
(edited on: 2010-07-22 09:06)
@Rafal99: It's a freshly genned .10 Fortress, I haven't played since .03 because of the broken military.
There are two possible reasons as my last fight DID work out very well...
Either the wooden crossbows were causing the discrepancy OR those ambushing lashers had extreme armor / dodging skills, as the siege a season later was broken easily thanks to the same Marksdwarves.
I'm thinking it's the wooden crossbows (some were even firing bone bolts and blew through a goblin's helmet breaking the skull and tearing the brain out ^_^ )
(0017662)
Logical2u   
2011-05-08 14:27   
Has anyone done any more experimentation on this? It sounds like it might be fixed.
(0020311)
Footkerchief   
2012-02-20 18:54   
Bolts are now overpowered if anything.