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[sjaakwortel]

Are we all forgetting that cats always land on their feet?

[ledgekindred]

Shortly after my first post in the thread, I got another group of volunteers arrive.

TL;DR version - it seems that even really big falls (I tested 20z and 30z) will result in primarily broken bones, with a chance of death if they land on their head.

No difference between a "skinny" goblin thief and a gigantic jabberer.  Broken bones abound.  And if they manage to damage their lungs there is a high chance of death to suffocation later on.

No differences between goblins stripped of their gear and armored goblins.

Most disappointing result - no more splashdowns.  They land intact, and either die immediately due to brain-crushage, or pathetically attempt to crawl away.  I built my drop-pit originally to try to get chunks.  No chunks.

Landing on upright spikes is instakill in every test I did.  But still no splash.  Same thing for a weapon trap with masterwork iron discs in it.  They tend to die before the discs are capable of doing much damage, due to the overall fall damage I guess.

Seems like nowadays the best way to get gibs is to pit your prisoners volunteers into your axedwarf barracks and hope for some lucky, severing strikes.

[Graebeard]

It sounds like the falling damage code may have been re-written to change from a whole-body impact with the possibility of limb-severing to a specific impact situation where one limb or part of the body will take the full impact of the entire fall.

If so, then falling 30 z's wouldn't be too much of a problem so long as 100% of the damage happened to, say, your left leg.  Change that to your head or your back, though, and instant death or imminent suffocation would follow.  Maybe this explains the new 30% - 40% fatality rate?

Edit: this may also explain why larger animals are less likely to die from a high fall: if they have more body parts to land on they are less likely to land on their head or back.

[Spinning Welshman]

It sounds like the falling damage code may have been re-written to change from a whole-body impact with the possibility of limb-severing to a specific impact situation where one limb or part of the body will take the full impact of the entire fall.

If so, then falling 30 z's wouldn't be too much of a problem so long as 100% of the damage happened to, say, your left leg.  Change that to your head or your back, though, and instant death or imminent suffocation would follow.  Maybe this explains the new 30% - 40% fatality rate?

Edit: this may also explain why larger animals are less likely to die from a high fall: if they have more body parts to land on they are less likely to land on their head or back.

I hope this isn't the case. The previous system of things exploding on impact might have been somewhat unrealistic, but it was certainly more realistic than energy not travelling through the body of a falling creature at all...

As an example: If I fell 30 foot, and landed on my feet, some of the energy of that impact would transfer up into my spinal column, with enough force that could break my spine. I know this isn't what was happening before in df, but it was closer to it, at least.

[khearn]

My free time has been in short supply the last couple of days (repaving a patio), but I've got test group #2 in mid-fall at the moment. I'm advancing time one tick at a time and keeping notes on when each test subject falls to which level so I can figure out what each dwarf's acceleration is. Even after just 32 ticks, it's been interesting.

I made sure each dwarf was in a different tile at the start, and recorded where each one was. After 12 ticks, I noticed that some of the dwarves had moved laterally and at that point I had two spaces that each had a pair of dwarves. So much for avoiding having any landing on each other. :-P

I'm dropping them from a retractable bridge. Of the 10 Dwarven volunteers in the test group 3 fell down the first level after 10 ticks, 2 after 11, 3 more after 12, and one slowpoke didn't fall until after 14 ticks.

I've also had 3 collisions on the way down. In none of them were there two dwarves in the same space, but all were in spaces adjacent to one of the walls of the test chamber. So it appears that the dwarves are bouncing off the walls on the way down. The cleaning crew is going to have a hell of a time getting the blood off the walls 23 or 26 levels above the floor. In each of the collisions, the dwarf in question slowed down a lot. All three were falling about 1 level per 2 ticks when they hit, and they slowed down to 1 level per 5 or 6 ticks.

After 32 ticks, the fastest dwarf is down to level 17 (they started at 30), and the slowest that hasn't hit a wall is at level 23. One of the wall-bouncers is still up at level 24, due to losing speed due to friction against a rough stone wall. Hmmm, an idea for future science: Would a dwarf loose less speed (and possibly take less damage) if the walls were smoothed?

Hopefully I'll get a chance to get more done at lunchtime. I hate to leave everyone hanging (especially the test subjects).

[ab9rf]

I made sure each dwarf was in a different tile at the start, and recorded where each one was. After 12 ticks, I noticed that some of the dwarves had moved laterally and at that point I had two spaces that each had a pair of dwarves. So much for avoiding having any landing on each other. :-P

Retractable bridges toss the items and units on them randomly when the bridge retracts; this can introduce horizontal velocity.

[Graebeard]

I made sure each dwarf was in a different tile at the start, and recorded where each one was. After 12 ticks, I noticed that some of the dwarves had moved laterally and at that point I had two spaces that each had a pair of dwarves. So much for avoiding having any landing on each other. :-P

Retractable bridges toss the items and units on them randomly when the bridge retracts; this can introduce horizontal velocity.

I wonder whether randomly introduced vertical velocity would also account for the differing (initial) fall rates.  Someone falling straight down would "land" before their buddy who got tossed slightly upwards by the bridge.

[Grumman]

Most disappointing result - no more splashdowns.  They land intact, and either die immediately due to brain-crushage, or pathetically attempt to crawl away.  I built my drop-pit originally to try to get chunks.  No chunks.

Mine got chunks. It's a trash compactor that extends from the top of the tallest mountain to the magma layer - a total of 50-70 z-levels. A goblin thrown in at the top explodes at the bottom.

[khearn]

Test group 2 has landed. I think most of you will be pleased with the results. After a 30 z-level fall, 90% were immediately dead, with 80% fully dismembered (with parts flying as high as 2 levels above the floor of the test chamber).

It was very odd, of the 9 dead, 4 dwarves had announcements of their death (`Subject 2B' Darosiden. Test Subject has died after colliding with an obstacle) and no combat report, 1 had no announcement but did have a combat report ("The test Subject slams into an obstacle and blows apart" with no other hits reported), 3 had no announcement nor combat report, and 1 had both an announcement and a combat report (9 hits, including skull -> brain). The survivor had no announcement (yet) and did have a combat report (8 hits, including upper spinal damage that should be fatal very quickly).

Ah, I just noticed that the dead test subjects that had no announcements are reported in the 'u' list as missing, while those that had announcement s are reported as deceased. That makes sense. I expect they'll get announcements as soon as the cleaning crew comes to tidy up the test chamber. I'm not sure why some are still reported as missing, given that there is a surviving test subject on the floor of the test chamber (he's even conscious, for the moment). I don't see a pattern involving how close other falling subjects were. One of the missing had 2 test subjects still in flight on the bottom level when he finished the test, so they should have seen him.

Two dwarves failed to disassemble, and took 8 or 9 combat hits, shattering bones and doing fatal damage (either immediate death, or mortal wounds).

I would guess that if you dropped enough dwarves, you might get a few that were lucky enough to not disassemble and even survive the multiple hits. But more testing would be needed in order to even make an estimate of what the survival rate would be. It seems extremely unlikely that any would be able to walk/crawl away, or even remain conscious. A peasant with a sock standing by near the bottom would be sufficient to finish them off.

Three dwarves did collide with the walls on the way down. This slowed them considerably and resulted in them being the last three to finish the test procedure. The two test subjects that failed to disassemble on impact were both involved in collisions on the way down, and I would guess that they didn't disassemble because they weren't moving as fast as the others. However, one that hit a wall on the way down did disassemble upon completing the test, so using the walls for braking isn't a guarantee of an intact corpse (nice try, though).

The fastest subject finished the test in 48 ticks, the slowest that avoided interaction with the walls finished in 56 ticks. The three that slowed down to put red graffiti on the walls took 61, 66 and 66 ticks. Their next of kin would be sent cleaning bills for the graffiti, except that we were careful to make sure that no one in the test group had any relatives that weren't also in the test group.

We plan to repeat the test with goblin test subjects, as soon as some show up and volunteer. The cages welcome mat is already in place for them. I may also try doing some testing using hatches instead of a retracting bridge to see if that will give more consistency in lateral as well as vertical accelerations. I may also did the test chamber deeper, it's in a spot that can be extended all the way down to 119 z-levels deep. We could do 120 if we want a magma landing, but I don't think we'd learn a whole lot from that. It would make the cleaning crew's job easier, though.

TL;DR: 30 z-levels does seem to be sufficient for 90+% kills, with 80% disassembled on impact. \o/

[misko27]

TL;DR: 30 z-levels does seem to be sufficient for 90+% kills, with 80% disassembled on impact. \o/

Well I guess my death pit needs to be bigger then.

[ledgekindred]

TL;DR: 30 z-levels does seem to be sufficient for 90+% kills, with 80% disassembled on impact. \o/

well I guess my death pit needs to be bigger then.

Same here.  I demand salsafication!

[HiEv]

I'm dropping them from a retractable bridge. Of the 10 Dwarven volunteers in the test group 3 fell down the first level after 10 ticks, 2 after 11, 3 more after 12, and one slowpoke didn't fall until after 14 ticks.

He probably didn't look down at his feet until then.  ;-)

Some other tests worth trying:

Dropping using hatches (as you already mentioned above)
Dropping onto spikes (as imperium3 and possibly others have suggested)
Dropping things onto dwarves

For the last item you might have a setup where you have dwarves standing under hatches, those hatches are attached to a lever, and have various items on top of those hatches.  You could vary the weight of the items and number of z-levels between the hatches and the dwarves to see how weight and height affect the damage, and you could also vary armor, to see if it provides any protection.  (I'd recommend saving, running the test, savescumming, digging the testing area down a level, and repeat, for less variables.)

[Kassil]

It's the same reason a feather falls slower than an equal mass of lead

Just a little side thing I felt the need to point out:
That actually has nothing to do with mass, weight, or size, but entirely with friction. All objects fall at the same exact rates, regardless of anything, except for the friction that slows them down, which on the planet earth, is mostly air friction. That is why a feather will fall slower. It has been tested on the moon where there is no air friction, the feather fell at the same exact speed as a wrench or something else that was heavy they tested it with.

You are correct, of course, if overly pedantic.
The feather, having greater volume compared to mass, has more surface to interact with the atmosphere and generate wind resistance and thus friction with the air.
For the purposes of the discussion, however, it amounts to exactly the same thing.

[Darkening Kaos]

This is all highly valuable intel.......but I have one burning question.

If you made your pit 1 tile wide and 30-odd deep and dropped a group of volunteers in such a way that they hit the sides as often as possible, will they ever reach the bottom?

[richieelias]

I too have noticed falling damage being nerfed significantly. New doors have been opened though apparently with falling objects imparting their energy onto whatever they land upon. This makes making landmines so much simpler. Boulders 2 levels above resting on a hatch linked to a pressure plate... "Rock traps" are finally effective!