D&D and Physics Models

[Aelfinn]

In my opinion, d&d 3.5's physics model is too simple. Sure, its good for on-the-fly fall damage calculations, but in most other situations, you have to try and model real-life physics and somehow convert that to modifiers and damage. Recently, in the campaign I was DMing, a player fell down a rough, stone, curving shaft about 120 ft deep. The session just stopped while a couple of players and I tried to model the physics of it, i.e. calculating the friction coefficient and then the bludgeoning damage. Does anybody know an easier way to do this?

[Red Fel]

Does anybody know an easier way to do this?

Sure do. Don't. See, that was easy.

Look, people joke about the whole "god kills a kitten" thing, but the fact of the matter is that D&D is bad for modeling realistic anything. Physics. Geometry. Economy. Healthcare. Feline lethality. D&D abandoned all pretense of realistic modeling long before it put caps on falling damage and expressed the planet's surface in five-foot squares and time in six-second turns. Trying to do model anything realistic is going to give you a headache. Or a tumor. Or cause insanity. Or drive your headache-causing tumor insane.

[Lightlawbliss]

In my opinion, d&d 3.5's physics model is too simple. Sure, its good for on-the-fly fall damage calculations, but in most other situations, you have to try and model real-life physics and somehow convert that to modifiers and damage. Recently, in the campaign I was DMing, a player fell down a rough, stone, curving shaft about 120 ft deep. The session just stopped while a couple of players and I tried to model the physics of it, i.e. calculating the friction coefficient and then the bludgeoning damage. Does anybody know an easier way to do this?

YOU MURDERER! HOW DARE YOU KILL CATGIRLS SO CASUALLY!!

On a more serious note, if your entire group enjoys those in depth calculations then more power to you, but most people find the extra realism detracts from the fun. Hurting peoples fun typically isn't worth it in a game.

[Elkad]

In the example, I'd just rule0 it.

I'd stick a distance modifier on it.
Rough slope (probably resulting in tumbling about). Half damage. Smashing into outcroppings does some damage, but the protrusions and high friction limit your top speed.
Slick slope. Half distance. Nothing to hold on to, so eventually you reach the same speed.
If the slope levels out gradually at the bottom, I'd knock some speed (distance for damage) off.

I'd still allow Tumble checks to reduce the distance. And maybe Balance checks on the slick slope.

And no, neither of those follows physics either.

[Larrx]

Okay, the above posters have given some sound advice (this is probably a fool's errand), but I'm bored. Quick napkin math for the example given is quite simple. The distance traveled doesn't mater, only the height difference and friction, and it's a simple proportionality. (1 - coefficient of friction) * damage taken from falling from an identical height. Terminal velocity would be capped in a like way, so with a coefficient of 0.25, max damage would be 15d6. How you're eyeballing coefficients of friction, I have no idea.

I'm not sure why you'd want to do this in a game, but it that's how you have fun more power to you. Vagaries of falling, sliding, and landing are adequately modeled by the random element of rolling the damage and the abstraction that is current hitpoints. YMMV.

note: yes, I know the frictional force depends on the normal force which depends on the slope of the slide, but bringing trigonometric functions to the table is too much even for me :) and since we're guesstimating friction anyway just factor that into the guess.

[Arael666]

On a completely unrelated topic, what's the deal with catgirls? I see them mentioned every other thread, is this some inside joke?

[Aelfinn]

At first, I did intend to make a quick ruling on damage, and I did, but one player argued that what I said (6d6 damage) was totally unrealistic and that he would take much higher damage, as rough stone has a much higher friction coefficient than 1. The player that was falling joined in, saying that because he was wearing armor, it wouldn't hurt him. It took us about 5 minutes to determine how long his armor would last (not long), he asked to make a tumble check. He rolled a natural 1 on the tumble roll, a skill he had a penalty with, and so I ruled that he would take 4d6 bludgeoning damage from smashing into things. Together, the two players, using calculus and trig, figured out how many newtons of force he was taking. Then we came to this problem: How many newtons are 1 damage? Right in the middle of this, a third player who had been using his laptop while we debated, leaned over and showed the first guy his screen, saying: "Hey, look, its a cat with a prolapsed anus. Isn't it cute?" We laughed, realizing that we had completely derailed the session, and it was pretty clear that no human, even a superhuman adventurer, could take that kind of beating and just walk away. He died, a mangled mess at the bottom of the slope.

I do realize that d&d is not meant to simulate physics, and that what we have done here was not the right thing to do, but it is necessary to maintain some level of realism.

[Stegyre]

On a completely unrelated topic, what's the deal with catgirls? I see them mentioned every other thread, is this some inside joke?
See this page (http://knowyourmeme.com/memes/every-time-you-masturbate-god-kills-a-kitten) for a general history of the meme, "Every time you ____, . . . ." (WARNING: some may regard it as NSFW)

If you go down to the bottom of the page, where recent images are posted, the apt one is (currently) the first: "Every time you try to drag real physics into a discussion about a fantasy comic, God kills a cat girl. Please think of the cat girls."

[Ashtagon]

http://www.thepiazza.org.uk/bb/viewtopic.php?f=70&t=2545

(Sorry catgirls)

Basically, I capped falling damage at 60d6 (since 600 feet is approximately the falling distance at which a tumbling human will attain terminal velocity).

[Milodiah]

Aaah, D&D...where pi = 4...

Personally I find the WoD Mage explanation to fit oddly well with D&D...the fabric of reality is just something everyone agrees on, and it runs away every time a mage walks up anyway.