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hamishspence
2010-09-28, 08:00 AM
I was idly speculating on some of the oddities of D&D damage, and wondered how much of a difference tying damage to kinetic energy would make.

For example- if you fall, the damage you do to yourself would be based on how heavy you are as well as how fast you're moving.

The mass of your weapon would make a big difference to damage.

And so on.

Might it fix some of the less plausible things?

Yora
2010-09-28, 08:04 AM
One question: Why?

Would it improve the story, or the fun of winning encounters, to add complex calculations of velocity and mass?

hamishspence
2010-09-28, 08:05 AM
Might fix some of the more broken things. Then again, it might not.

Done right- maybe it could bump up melee damage so that it scales well?

If, for example, a person Full attacking with a weapon can make 4 attacks per round, this would imply the weapon is moving very fast- so doing more damage.

Eldan
2010-09-28, 08:13 AM
However, you should also calculate how fast you can swing that heavier weapon, and if it actually changes damgae :smallamused:

hamishspence
2010-09-28, 08:15 AM
True- might give heavy weapons an even bigger bump than they have already- and make strength much less important than the speed the weapon is swinging at.

Maybe charging would allow you to add your speed to your weapon speed.

And, when set to receive a charge, you use the speed your enemy is moving at- and possibly their weight instead of the weapon's.

Tetrasodium
2010-09-28, 08:17 AM
For example- if you fall, the damage you do to yourself would be based on how heavy you are as well as how fast you're moving.

The mass of your weapon would make a big difference to damage.

Gravity doesn't work that way on the first point. A feather doesn't fall slower than a brick because it's lighter, it falls slower because of how its structure impedes it's movement through the air. A 50 pound humanoid and a 300 pound humanoid both lack anything to impede their movement in any significant way unless it's one of the less common winged humanoids (i.e. raptorians) or they have featherfall or something. Both the 50 pound humanoid and the 300 pound humanoid have a bone and muscle structure capable of handling their weight in roughly the same level of effectiveness.

With regards to your point about weapon damage being affected by mass, that somewhat already exists when you consider the ridiculous mercurial weapons. It's certainly possible there is a book that says a lead core mace/morning star/etc gives it a nonmagical +1 bonus or something. Plus there is nothing that says it's not involved in creating magical weapons anyways, ECS (or a different eberron book) rattles off a bunch of magical items in the DMG that use various dragonshards in their construction when it's going over dragonshards and some interesting uses for them for example.

Lapak
2010-09-28, 08:28 AM
I was idly speculating on some of the oddities of D&D damage, and wondered how much of a difference tying damage to kinetic energy would make.

For example- if you fall, the damage you do to yourself would be based on how heavy you are as well as how fast you're moving.

The mass of your weapon would make a big difference to damage.

And so on.

Might it fix some of the less plausible things?The physics involved is complicated enough that you're likely to end up with equally wrong results through a much more difficult process. More mass doesn't mean more kinetic energy if the weapon is slow; note that real-world weapons weren't that heavy. More attacks does not mean any individual attack is moving faster; it might just mean that the attacker is better at creating or exploiting vulnerabilities in the enemy's defenses while the amateur flails around a bit. Falling damage is much more involved than just weight.

So any attempt to make damage accurately reflect reality would either require too much calculation every time someone gets hurt or would fail in its goal, I think. (And all of that leaves aside what 'damage' actually means in gaming, itself a topic of constant debate.)

Snake-Aes
2010-09-28, 08:45 AM
Might fix some of the more broken things. Then again, it might not.

Done right- maybe it could bump up melee damage so that it scales well?

If, for example, a person Full attacking with a weapon can make 4 attacks per round, this would imply the weapon is moving very fast- so doing more damage.

I believe it will only complicate things more than it is worth. For example, how will you differentiate bludgeoning damage from piercing or slashing damage given the only difference between them is the area they are applied to?

jseah
2010-09-28, 08:48 AM
Well, it seems logical to me to treat the idealized case of Object A of mass Ma travelling at speed Va collides with Object B of mass Mb travelling at speed Vb.

Shape and structure should be a matter of DM handwaving, so at best guidelines for those. D&D players cannot be expected to do complex fracture simulations on paper... =P

A good formula should also yield the same result if it was Object B moving towards Object A (in the same orientation of course), being that the situation is a simple frame shift of the original.


I have a houserule in my games correcting free fall speeds and dmg though. It always bugged me about how slow stuff falls in D&D.
Falling damage does not cap
Falling speed is 180ft in round 1 and increases by 360ft per round for every round afterwards (180, 540, 900...)

Falling damage is 1d6 bludgeoning per 10lbs per 20ft falling speed.
Both the falling object and the object it hits take this damage.

hamishspence
2010-09-28, 09:00 AM
I have a houserule in my games correcting free fall speeds and dmg though. It always bugged me about how slow stuff falls in D&D.

Falling damage does not cap
Falling speed is 180ft in round 1 and increases by 360ft per round for every round afterwards (180, 540, 900...)

Falling damage is 1d6 bludgeoning per 10lbs per 20ft falling speed.
Both the falling object and the object it hits take this damage.

This is roughly the sort of thing I was thinking about- maybe something similar might apply to creatures which one might expect to attack via ramming- a whale, a swordfish, and so on.


Both the 50 pound humanoid and the 300 pound humanoid have a bone and muscle structure capable of handling their weight in roughly the same level of effectiveness.

In game, a 60 pound Medium humanoid and a 300 pound Medium humanoid with the same strength, can lift the same amount over their head.

While "lower terminal velocity" might account for some of the survivability of small creatures falling, "lower kinetic energy" probably also plays a big part.

Snake-Aes
2010-09-28, 09:04 AM
Now take into account friction to determine the terminal velocity.

hamishspence
2010-09-28, 09:08 AM
I did mention "lower terminal velocity" as part of it.

If you could have two creatures of roughly the same size and shape (but one weighing twice the mass of the other) while they'd hit at roughly the same speed, the heavier creature would take a bigger shock.

Esser-Z
2010-09-28, 09:08 AM
The main issue is the gameslowdown that comes from doing all that phsyics. Also from some people ALREADY being afraid of the math there is, so adding more (especially complicated-looking, even if really not so hard) is not a very good idea.

Really, abstracting damage is fine. I do believe there are rules for heavier objects dealing more falling damage--I know Telekinetic Thrust takes this into account in a nicely simple way.




The mass of your weapon would make a big difference to damage.

I believe this is represented by different damage die sizes. A Greatsword does 2d6, while a Longsword does 1d8, because a greatsword is bigger.


Air resistance is mostly meaningless for most falling things--they're likely to be PCs or rocks or such, none of which have significant increased resistance, at least not for these purposes. So, falling speed is roughly constant (though I'm not sure how D&D handles fall speed and acceleration) for just about anything we care about. This is good.

Now, while mass doesn't matter for speed, it does indeed affect impact strength... This probably doesn't matter too much for PCs. Outside constructs and monsters, they usually weigh close enough to the same values to not have significant impact variance, I imagine. For heavier things, extra damage based on size (See the Telekinetic Thrust power again. It even takes the composition of the object into account!) sounds reasonable.

grimbold
2010-09-28, 09:08 AM
i think this is accounted for in the fact that weapons can hit harder due to strength bonuses. Also bigger weapons tend to do more damage. The physics would be a pain if you really want to make it +1 damage w/ all 2handed or larger weapons.
maybe +2 for large weappons and scaling up on the same rate (+3 for huge, +4 for Gargantuan, i hope i got my size classes right)

hamishspence
2010-09-28, 09:10 AM
True- might work better for things which are very obviously chunky, high speed objects.

I was thinking along the lines of

"given that a stone of X weight hurled at a target Y distance away by a hulking hurler does Z damage, how much damage should other weapons be doing relative to that?"

Snake-Aes
2010-09-28, 09:13 AM
I did mention "lower terminal velocity" as part of it.

If you could have two creatures of roughly the same size and shape (but one weighing twice the mass of the other) while they'd hit at roughly the same speed, the heavier creature would take a bigger shock.

I'm not sure we talked about the same thing. Terminal velocity is the maximum speed the object will achieve. That is added to the fact many small creatures don't even take falling damage ever, just like small mice can fall from the top of a building and run like nothing happened.

hamishspence
2010-09-28, 09:16 AM
And the reason they do that, isn't because their terminal velocity was much lower- but because their kinetic energy was much lower.

In D&D- if you drop a really tiny animal from a high place- splat. If you drop a much bigger animal from the same height, it has a chance to survive due to high hit dice.

When it should be the other way round.

Esser-Z
2010-09-28, 09:17 AM
Aha, yes. The Falling Damage rules do have a nice simple approximation for increased weight=increased damage, and a clause for very light objects not doing any. This is good.

On the other hand...it completely lacks rules for how fast an object falls, or in game terms how far a falling object moves per round. This is harder to resolve than it would see, as D&D tends to not have much of a concept of acceleration. Hmm.

Hamish: That higher HD creature also has a much better chance (IE, pretty much 100%) of being stabbed with a sword. HP's... a mess. :smalltongue:

hamishspence
2010-09-28, 09:19 AM
Light objects- but not creatures. (A mouse falling on you from a great height won't hurt you, but the mouse is in deep trouble).

Maybe the rule should be expanded to include damage to objects and creatures from falling, not just damage from them.

Snake-Aes
2010-09-28, 09:21 AM
Light objects- but not creatures. (A mouse falling on you from a great height won't hurt you, but the mouse is in deep trouble).


It wouldn't, really. the light build is the main reason they can drop high heights and not care.

hamishspence
2010-09-28, 09:22 AM
It wouldn't, really. the light build is the main reason they can drop high heights and not care.

That's the way it works in real life- but apparently, not in D&D.

Esser-Z
2010-09-28, 09:23 AM
D&D and real life don't match up in many, many ways.

This, like other things, can be blamed on residual magic. :smalltongue:

As for those little animals and falling... A small rodent can be potentially badly injured from just a several foot drop, so...

hamishspence
2010-09-28, 09:25 AM
Hence the idea of, if not making it match precisely, at least trying to make some things make a bit more sense.



As for those little animals and falling... A small rodent can be potentially badly injured from just a several foot drop, so...

That might be a case of rolling, and getting more damage than they have HP :smallamused:

Terazul
2010-09-28, 09:27 AM
On the other hand...it completely lacks rules for how fast an object falls, or in game terms how far a falling object moves per round. This is harder to resolve than it would see, as D&D tends to not have much of a concept of acceleration. Hmm.


It has a few. For example, a stalling flying creature (who isn't moving his minimum speed) falls 150 ft in a round. And then 300 ft. And feather fall reduces falling speed to 60 ft a round. But yeah, I really don't see the benefit of trying to suddenly apply physics to everything. Especially when magic starts getting involved.

Snake-Aes
2010-09-28, 09:28 AM
That's the way it works in real life- but apparently, not in D&D.

Then what are you doing trying to adapt real life into d&d? :p Because if "small creature dies but big one doesn't" irks you, it's kind of a double standard to forbid the small creature to not taking damage in the first place.

hamishspence
2010-09-28, 09:31 AM
Mostly because the DMG says that for most things D&D worlds generally obey the same principles as the real one-

and the fact that they really don't, could maybe do with fixing.

It's more idle speculation than a serious attempt though.

Small creatures should be taking damage from falling- but much less than big creatures- so much less, that there should be a chance (if a small one) of survival.

jseah
2010-09-28, 09:31 AM
^Redid the calculations to base them off 9.81m s-2.

Falling damage does not cap
Falling speed is 190ft in round 1 and increases by 190ft per round for every round afterwards (190, 380, 570...)

Falling damage is 1d6 bludgeoning per 10lbs per 20ft falling speed.
Both the falling object and the object it hits take this damage.

Distance fallen is 570ft times number of rounds squared.

It's a bit more than this, but I can chalk up the shortage of a few feet to air resistance... or more honestly, plain laziness. =P

A slightly more accurate one would be to take damage based off relative speed of the two objects, but that gets into trigonometry so nvm.

EDIT:
This scales the damage with momentum.

Eldan
2010-09-28, 02:13 PM
Obviously, you looking at falling damage from the wrong angle.


Let's first take into account that all matter in the universe is actually composed of differing amounts of fire and pneuma. We can assume that a small living creature and a large living creatures have both the same number of atoms of pneuma, as they are equally complex, and the same amount of fire spirit, as they are both equally alive.
Let us assume that the small animal is a mouse, and the large animal a horse.
The horse is not only larger, but also heavier than the mouse. Since they consist of the same number of atoms, we can therefore conclude that horse atoms are larger than mouse atoms.
Now, let us come to the issue of falling. As we all know, the pneuma of air is less dense than the pneuma of ground, as it's atoms are spread further apart.
It has been proven consistently by many great sages that all atoms are possessed by a strong love for each other, and that only random movements outside their control move them apart.
As we now look at the elephant and the mouse, they both have the same number of atoms, as I previously stated. Therefore they receive the same amount of love from the ground.

So they also fall at the same speed. I see no problems with this conclusion.


In related news: guess who just had a lecture on the history of life sciences, starting with a few noteworthy Greeks, Ionians and so on.

Eric Tolle
2010-09-28, 03:02 PM
^Redid the calculations to base them off 9.81m s-2.

Falling damage does not cap
Falling speed is 190ft in round 1 and increases by 190ft per round for every round afterwards (190, 380, 570...)

Falling damage is 1d6 bludgeoning per 10lbs per 20ft falling speed.
Both the falling object and the object it hits take this damage.

Distance fallen is 570ft times number of rounds squared.

It's a bit more than this, but I can chalk up the shortage of a few feet to air resistance... or more honestly, plain laziness. =P

A slightly more accurate one would be to take damage based off relative speed of the two objects, but that gets into trigonometry so nvm.

EDIT:
This scales the damage with momentum.

Actually, you've got some major problems with this formula, and it makes it no more accurate than regular D&D.

For a start, there has to be a cap on falling damage, based on air resistance. For a start, if there's no cap to falling damage, then obviously items are falling in a vacuum, and we need to use the suffocation tables before worrying about damage (actually those tables are inaccurate as well: roughly, in a vacuum creatures will pass out in 2-3 rounds (being generous), and start taking permanent damage in 20 rounds, and die immediately after that. please adjust your rules accordingly). :smallbiggrin:

Secondly, for most purposes maximum velocity is going to be based on both the distance fallen, and the acceleration minus drag, a = (W - D) / m. The drag equation of course is D = Cd * r * V ^2 * A / 2 , so quickly working out the reference area and the Drag Coefficient ( Cd = D / (A * .5 * r * V^2) ) will give you the final equation. Terminal velocity then is going to be:

V = sqrt ( (2 * W) / (Cd * r * A)

See? No trig at all! And naturally easy enough to figure out in game when you have the right tables of mass, density and reference area printed out.

Note that the maximum velocity doesn't increase linearly according to mass, so basing damage directly on mass won't work.

Finally, maximum velocity is going to vary between 14 and 300 ft./round at most, so the velocity will usually be capped after one or two rounds (for most humanoids, one round is fine. So once we have all that, we can easily calculate the damage based based on the standard D&D velocity/impact tables.

Waitasecond...we don't HAVE "Standard D&D velocity/impact tables? Well no problem, we can probably just use your handy "Handbook of Engineering Fundamentals" to calculate that.

OK? Go ahead and reconfigure your calculator to encompass this new information. If you need some assistance, here's a handy Terminal Velocity Calculator (http://www.calctool.org/CALC/eng/aerospace/terminal).

And don't forget to show your work.:tongue:

jseah
2010-09-28, 03:16 PM
Eric:
Yes, I did assume a fall in a vacuum in my calculation.
I also generally try to avoid square roots in any calculations, calculating drag is a bit... >.>

Then again, it's nice to see someone else willing to put up the formulae, most especially since I don't know them.
Also, your link gives me a 404... =/

PS: the trigonometry I mention is needed for working out the relative velocity of two objects moving in arbitrary 3D space.
eg. working out the collision damage for a hero jumping out an airship and landing on a gliding dragon's back.
Trig (specifically cosine rule) might be needed to work out the relative velocity vector. Of course, that's if the dragon isn't going horizontal coz in that case the pythagoras theorem will do.

Skorj
2010-09-28, 03:21 PM
I've gone down this road before. Far down this road. :smalleek: There is no "win" at the end of this road. Energy (not just kinetic) is simply not a good measure of damage inflicted, at the levels of energy we're talking about in D&D, as too many other factors matter, especially the elasticity and hardness of, well, everything. Falling damage, for example, is extremely variable in real life: people die from 5 foot falls, and survive parachute failures.

Even if you're simulating bullet damage, energy is a poor guideline for damage (mostly due to overpenetration), and experts disagree (read argue furiously) about energy vs momentum. This is an important consideration for design of real world weapons upon which many billions of dollars are spent, and still experts disagree.

Only once you get to the energy levels involved with cannons does energy start to become a solidly useful factor in calculation, and even then it's just a multiplier to combine with many other factors.

ericgrau
2010-09-28, 03:23 PM
I think introducing "physics" to damage will only cause an arbitrary imbalance that will screw up the game. I put "physics" in quotation marks because no one will be able to do anything all that precisely, and what your'e really doing is tossing in a bunch of numbers that might as well be random into your game and then living with whatever messed up anarchy may happen.

As for falling potential energy is directly proportional to height, and so is damage. Ya there are other factors involved, but twice as much height does in fact hurt twice as much. Terminal velocity will cap the damage, but IIRC the cap from terminal velocity would come a bit higher than 200 feet. Having a falling creature fall X feet in the first round and 2X feet every round thereafter is actually quite accurate, as you hit terminal velocity by round 2 (and if you do the numbers acceleration does make you half as fast round 1). The rules use 150 feet and 300 feet for flying creatures that stall and fall, though real gravity would be closer to 500 feet and 1000 feet. 6 seconds is a long time to fall.

gomipile
2010-09-28, 03:29 PM
Mathematically speaking, this would open the Hulking Hurler problem up to all strength based classes. Everyone's damage would scale exponentially with gains in strength.

Spiryt
2010-09-28, 03:39 PM
Holy honcking hell....

All I can said that Roberto Carlos could quite regularly speed up a ball to over 40 m/s, giving it energy of at least 300 J, if it's weight was on the lower end of scale for regular footballs.

It's 2 times more KE than arrows from the mightiest longbows.

Is the ball going to be even comparatively deadly to humans, compared to such arrow?

Or more sensibly - is it going to behave similarly at all?

As far as first thing goes - no footballers were being hit with Roberto's shoots quite often - it's normal part of the game, and obviously, some pain was worst consequence.

KE doesn't matter in 1% as much as what has such energy and what will happen with such energy.

That's all from me.

ericgrau
2010-09-28, 03:41 PM
That of course is because footballs aren't sharp. Energy is still most of it, it's just that there are other factors too. Now try a knife without much kinetic energy. Also not very effective.

Though I'm still against the disaster of trying to apply all this to a game.

hamishspence
2010-09-28, 03:44 PM
Good point- the size, shape, and density of the object will play a big part. D&D has to abstractify a lot of things- but might it sometimes go a bit overboard with this?

ericgrau
2010-09-28, 03:47 PM
If, after thousands of hours of work to make it playable, I did make a game then I'd try something simple but semi-realistic like this:
Everything has a DR per unit area, but also a max damage per unit area. Weapons are rated with an amount of damage, area of contact and percent of max damage. Sharper weapons thus pierce DR easier, but have a lower maximum damage. Even then this falls apart on so many levels of realism it's silly, but it might be interesting at least.

jseah
2010-09-28, 03:49 PM
^The only place I suspect this speculation could make much of a difference is in falling damage.

Well, that and relativistic railguns. At around 0.1c, your shape and material starts to not matter so much.

Even at lower energy levels, some questionable calculations and lots of catgirl killing lead me to believe that a certain magical railgun can put out energies comparable to a tomahawk missile. At that point, as long as you're not shooting candy floss or something equally ridiculous, any solid object will blast through 10ft thick stone walls.
And probably not survive the impact regardless of material or shape.

ffone
2010-09-28, 03:52 PM
HP are an abstraction. There's no need for HP to be linear in momentum, energy, falling velocity, etc. as opposed to the square or square root. Since leveling up and healing spells are pure game concepts, rate of natural healing is the only 'real' thing HP needs to be linear in, but real healing doesn't work like that anyway (permanent crippling etc.)

Likewise, there is no need for a particular relationship between the damage aspect of Strength and carrying capacity; damage is the same scale and unit as HP, and a total abstraction. Since carrying capacity is exponential in strength, damage potential is logarithmic in carrying capacity, by definition.

The easy way to adjust DnD falling damage for passable consistence with real world physics is simply:

- Figure out what falling distance achieves terminal velocity (for, say, an average human, and we'll use that for everything - I'm sure the internet has typical personal terminal velocity and distance to achieve it it).

- Cap DnD falling damage at this distance.

Spiryt
2010-09-28, 03:52 PM
That of course is because footballs aren't sharp. Energy is still most of it, it's just that there are other factors too. Now try a knife without much kinetic energy. Also not very effective.

Though I'm still against the disaster of trying to apply all this to a game.

Uh, no.

It's because it's not sharp, round, not dense, hollow and filled with air, from soft material, elastic, without any sensible sectional density behind the "point" of impact, and 40 other things.

"Not much energy" can matter many things.

Good hunting arrow can over penetrate and mortally wound a bear with 40 J of energy.

While 0.22 rifle bullet generally needs at least 90J to do significant harm to the human TBOMK. Depending on exact weight and velocity.

So it's not really simple, and trying to implement it in D&D is kinda pointless IMO.


Now try a knife without much kinetic energy. Also not very effective.

You can push a knife trough many things, including humans, with slow, not very dynamic movement of your arms. Minimal kinetic energy, but it does harm, as knife is pushed trough the guts.

Cicciograna
2010-09-28, 03:59 PM
Some years ago I performed some calculations on the matter. I was specifically trying to determine a better way to parametrize falling damage. I started from the damage a moderately strong human deals by wielding a heavy mace, modeled his arm and the mace as rigid bodies and calculated the exchange of momentum in the strike. My aim was to establish a 1:1 correspondence between momentum exchanged and damage dealt, then apply similar calculations to a falling human-shaped body reaching limit falling speed.

It is not worth the effort. The numbers were so unbelievabily absurd that I abandoned the project. Besides, clearly my starting point was wrong, since the damage from an heavy mace is itself badly reflected by game mechanics...

ffone
2010-09-28, 10:14 PM
The problem with almost all these attempts is they try to make damage 'linear' in some physical quantity, without explaining why that's necessary.

It's clearly doomed to fail. Consider, for example, sneak attack. A Str 6 halfling with Improved Unarmed Strike or most any weapon can plink someone for 10d6.

Damage/HP are more keyed to biology/anatomy (and its structural integrity analogs for objects, constructs, etc.) than physics. Consider also natural healing - one of the few HP related effects which is nonmagical and defined by real units (time). Even then, since level and Constitution are abstract, it's not obvious that healing a certain rate per day is or isn't realistic.

The other reason it's doomed is the lack of injuries, and the 1 HP vs 0 HP thing that it's cliche to make fun of.

I do like capping falling damage with terminal velocity, because if two falls end at the same speed, you might reasonably expect the same damage on average (using your time to react to the fall, etc. is handled by Tumble.) This is a special case where have two different things that physics tell us have almost exactly the same 'terminal' characteristics.

For me, what's important is not the physical realism itself, even then, but for the rules to make just enough sense that characters behave realistically and needn't engage in metagame thinking. So for example if your character is currently in the air, grappled by a dragon, and trying make risk-trade-off decisions about tactics, then (if it's in-character fro this particular PC to know about terminal velocity and a rough sense of what starting height achieves it) it helps him play in-character. And even that is a crazy corner case that will never come up for most people.

hamishspence
2010-09-29, 02:56 AM
I like the notion of relating the terminal velocity damage cap to size- if a Tiny creature falls it takes very low damage, if a Fine creature falls it takes no damage at all- if a Colossal creature falls, it splatters.

gomipile
2010-09-29, 03:38 AM
I like the notion of relating the terminal velocity damage cap to size- if a Tiny creature falls it takes very low damage, if a Fine creature falls it takes no damage at all- if a Colossal creature falls, it splatters.

That makes a lot of sense, and I like the idea.

But think of all the catgirls under the Tarrasque!

Psyx
2010-09-29, 05:35 AM
D&D is a terrible simulation. trying to make it make sense is utterly futile. Just throw it out the window and buy...hmmm... anything else if you want more realistic rules.

Morph Bark
2010-09-29, 05:38 AM
Might fix some of the more broken things. Then again, it might not.

Done right- maybe it could bump up melee damage so that it scales well?

If, for example, a person Full attacking with a weapon can make 4 attacks per round, this would imply the weapon is moving very fast- so doing more damage.

Wouldn't the weapon also take damage if it were moving really really fast - at least nonmagical weapons?


Holy honcking hell....

All I can said that Roberto Carlos could quite regularly speed up a ball to over 40 m/s, giving it energy of at least 300 J, if it's weight was on the lower end of scale for regular footballs.

It's 2 times more KE than arrows from the mightiest longbows.

Is the ball going to be even comparatively deadly to humans, compared to such arrow?

Or more sensibly - is it going to behave similarly at all?

As far as first thing goes - no footballers were being hit with Roberto's shoots quite often - it's normal part of the game, and obviously, some pain was worst consequence.

KE doesn't matter in 1% as much as what has such energy and what will happen with such energy.

That's all from me.

You also have to take into account that a football is soft and absorbs the impact much better than something made of solid metal.


D&D is a terrible simulation. trying to make it make sense is utterly futile. Just throw it out the window and buy...hmmm... anything else if you want more realistic rules.

Exalted? FATAL? :smallamused:

hewhosaysfish
2010-09-29, 07:29 AM
I like the notion of relating the terminal velocity damage cap to size- if a Tiny creature falls it takes very low damage, if a Fine creature falls it takes no damage at all- if a Colossal creature falls, it splatters.

But isn't the physics behind this all to do with the cubic increase in mass compared to the square increase in surface area (and structural strength).
You know, the same physics that says a human-like creature scaled up to 50ft tall would break both its legs with its own body-weight?
Would a giant be able to stroll around perfectly happy in defiance of physics for as long as he was on level ground but take crippling falling damage whenever he stepped off a 5ft curb?

Psyx
2010-09-29, 08:29 AM
Exalted? FATAL?

I can't believe I'm sticking up for FATAL in any way, but at least both it and Exalted have wound systems which go beyond 'You're fine, you've been hit with an axe, a sword, a dragon's breath.... no penalties. Oh... now you're on negatives, you are bleeding and can't move, now you're dead'.

Quietus
2010-09-29, 09:07 AM
All I have to say on this matter is that if something actually makes the commoner railgun do actual damage, it should never see play.

ffone
2010-09-29, 03:38 PM
But isn't the physics behind this all to do with the cubic increase in mass compared to the square increase in surface area (and structural strength).
You know, the same physics that says a human-like creature scaled up to 50ft tall would break both its legs with its own body-weight?
Would a giant be able to stroll around perfectly happy in defiance of physics for as long as he was on level ground but take crippling falling damage whenever he stepped off a 5ft curb?

From the very fact that giants exist and function in DnD, we can infer that they are not just scaled up humans (who as you say, would be cripples in effect). Apparently their bodies are structurally designed/evolved to handle it, and perhaps 'stronger' in some sense that may or may not be purely captured by Strength - an ability score relating more to a creature's ability to exert force on other things, or carry extra stuff beyond its own bodyweight - note that your own bodyweight doesn't count against capacity.

Incidentally, vanilla hill giants have Str 25, or rather +14 Str as a 'race' (the vanilla has a pre-race Str 11), which corresponds to about an 8x capacity increase (doubling per +5). So they are 'twice as strong' as a human scaled up to their size.

Enlarge Person only gives +2 Str, for balance reason. So being Enlarged makes you relatively weaker - but I always just assume that the spell always somehow makes you stronger in a way (lower back etc.) that lets you support yourself still, but isn't reflected (very much) by Str. This is not a houserule, merely an in-character interpretation/roleplay of the RAW.

Here's an easy way to adjust falling damage for size:

the 1d6 per ten feet is like being hit by a 1d6 slam attack (per 10') the same size as yourself (Newtonian physics) - not the size of the planet.

DnD has nice rules for scaling damage with size. 1d6 becomes 1d8, 2d6, 3d6, 4d6 as you go from Med to Colossal, and then down to 1d4,... as you go Small and smaller.

So just use these values. Large guy take 1d8 per 10' increment.

If balance of the core races is at issue, keep the 1d6 for Small characters, and just adjust it from Tiny downward, or not at all. Sort of like how Small and Med tend to be the same for space/reach, probably a design decision to keep the PHB races more similar.

Note that while a fall of a given distance may look 'effectively further' for a small creature, falling distance matters because of the Newtonian acceleration due to gravity, not because of the number of body lengths of the creature that the distance is.