D&D 5E What rule(s) is 5e missing?

Oofta

Legend
The lack of accounting for mass in falling damage rules continues to irk me. It’s not missing from the rules just wrong.

Instead of the d6 it should be based on the size of the object/creature:

Tiny: no falling damage, they always effectively featherfall.
Small: d4
Medium: d6
Large: d8
Huge: d12
Gargantuan: d20
Yes and no. You'd have to figure out terminal velocity as affected by air resistance. I'm not convince falling a short distance should make a difference given how much fantasy ignores the effects of size.

Does a halfling really have so much less air resistance versus a human that it's going to matter over relatively short distances? This is basic Newtonian physics here, the only reason cats can fall large distances is because they are so light they can act as their own parachute. After a certain size, the air resistance might even decrease the damage taken. Of course large animals in the real world would take more damage from a relatively short fall because of how they are built, but most larger creatures in D&D aren't real world animals.

If you were really going to do something realistic, you would have the same number of dice for say the first 100 feet, then lower dice for every 100 feet after that (because your velocity increases less) until you hit terminal velocity at 1,500 feet.
 

log in or register to remove this ad


Laurefindel

Legend
Yes and no. You'd have to figure out terminal velocity as affected by air resistance. I'm not convince falling a short distance should make a difference given how much fantasy ignores the effects of size.

Does a halfling really have so much less air resistance versus a human that it's going to matter over relatively short distances? This is basic Newtonian physics here, the only reason cats can fall large distances is because they are so light they can act as their own parachute. After a certain size, the air resistance might even decrease the damage taken. Of course large animals in the real world would take more damage from a relatively short fall because of how they are built, but most larger creatures in D&D aren't real world animals.

If you were really going to do something realistic, you would have the same number of dice for say the first 100 feet, then lower dice for every 100 feet after that (because your velocity increases less) until you hit terminal velocity at 1,500 feet.
Force is proportional to mass so technically, the bigger the size of a creature (assuming bigger size implies higher overall mass), the bigger the impact. @robus proposition basically follows the adage that the bigger they are, the harder they fall.
 


glass

(he, him)
Force is proportional to mass so technically, the bigger the size of a creature (assuming bigger size implies higher overall mass), the bigger the impact.
Big things are more at risk from falls, but that is not the reason.

Force due to gravity is directly proportional to mass, but acceleration is inversely proportional to mass, so it cancels out. Bigger things fall faster in practive, but that is because the effect of air resistance is proportionately less, not because of the mass directly. In vacuo, everything falls at the same rate regardless of mass.

_
glass.
 

Garthanos

Arcadian Knight
Big things are more at risk from falls, but that is not the reason.

Force due to gravity is directly proportional to mass, but acceleration is inversely proportional to mass, so it cancels out.

acceleration due to gravity is constant (near earth anyway and the constant is called g and is 32fps squared or 9.8 meters per second squared)
 
Last edited:

Lanefan

Victoria Rules
acceleration due to gravity is constant (near earth anyway and the constant is called g and is 32fps squared or 9.8 meters per second squared)
Until you reach terminal velocity, which is different for everything depending how much air resistance that item generates vs its mass, meaning there's still going to be different amounts of damage done by each thing when it lands on someone. That's where the questions arise, I think.
 


Garthanos

Arcadian Knight
Yes it is. For the reasons I stated in the post you quote
Yes it is. For the reasons I stated in the post you quoted.
"but acceleration is inversely proportional to mass, so it cancels out "

The alteration due to air resistance does not simply "cancel out" unless and until you hit terminal velocity, (and the deceleration at the bottom is derived from your velocity) ie if you want to bring air resistance in you have much more complexity and they are not the same (including details of shape) even with a cube area (basic resistance) increases s squared distance across and mass increases as cubed. Squared cube law strikes again.
 
Last edited:

DND_Reborn

Legend
Tiny: no falling damage, they always effectively featherfall.
Small: d4
Medium: d6
Large: d8
Huge: d12
Gargantuan: d20
We just use the HD size for falling, so

Tiny: d4
Small: d6
Medium: d8
Large: d10
Huge: d12
Gargantuan: d20

Though if you don't mind, I am curious what your house rules for shields are.
Sure.
  • Buckler: +1 AC, 3 lb., d4 damage + DEX or STR, Finesse/Light properties so can be used in TWF easily
  • Round/ Kite:+2 AC, 6 lb., d4 damage + STR, TWF attacks made with disadvantage unless you have Dual Wielder
  • Tower: +4 AC, 15 lb. IIRC, sort of like 3/4 cover...but it doesn't count as that!, d6 damage, Heavy property, cannot TWF, but may be use for Bull Rush as an Action for d6 + STR mod and knock targets prone vs STR save DC = 8 + proficiency + STR mod. Creatures larger than you have advantage on the save.
Block: You can use your reaction to block critical damage with your shield so you take normal damage instead, but this sunders your shield. This can be done versus spell damage, falling damage, and other sources of critical damage.

Instead of critical hits on a 20, we do critical damage on damage rolls. If any dice rolled are the maximum, the die explodes and the damage is critical.

Parry: With a Buckler or Round/Kite shields you can also use your reaction to parry an attack, adding your proficiency bonus to your AC potentially causing the attack to miss. If you do this, however, you lose any bonus to your AC due to your shield until the start of your next turn.

Shield master:
  • Allows bonus action shove even if you don't take the attack action.
  • If you Bull Rush with a Tower Shield, the target has disadvantage on the save, and you can do it as a bonus action instead of an action.

I think that is everything... :)
 

James Gasik

Legend
Supporter
Thanks a lot, I rather like those rules, though I'd be tempted to add rules for spiked shields. I like parry, and it made me realize another thing we need rules for- defensive weapons like the main gauche.
 



glass

(he, him)
"but acceleration is inversely proportional to mass, so it cancels out "
Correct.
The alteration due to air resistance does not simply "cancel out" unless and until you hit terminal velocity
Or even then, but I never said it did. I said that force being proportional to mass and acceleration being inversely proportional to mass cancel out, so in vacuo everything falls at a constant acceleration (assuming constant gravity). Because it does and they do.

Once you add air resistance into the equation, that technically ceases to be true, but the effect of air resistance on creatures of human size and mass is negligable. AIUI, the effect on smaller creatures is considerably less negliable.

_
glass.
 

Garthanos

Arcadian Knight
Correct.

Or even then, but I never said it did. I said that force being proportional to mass and acceleration being inversely proportional to mass cancel out, so in vacuo everything falls at a constant acceleration (assuming constant gravity). Because it does and they do.

Once you add air resistance into the equation, that technically ceases to be true, but the effect of air resistance on creatures of human size and mass is negligable. AIUI, the effect on smaller creatures is considerably less negliable.

_
glass.
Cannot be correct as constants do not vary (within scope) so they are not inversely or linearly or anything else proportionate to any thing... the force remains proportionate to mass with as I agree slight reduction due to drag

F=mg.... where g does not change and mass does (as we are talking about larger vs smaller things)
 
Last edited:

glass

(he, him)
Cannot be correct
Can be, and is.

as constants do not vary (within scope) so they are not inversely or linearly or anything else proportionate to any thing... the force remains proportionate to mass with as I agree slight reduction due to drag

F=mg.... where g does not change and mass does (as we are talking about larger vs smaller things)
g absolutely changes, it just does not change enough to worry about for the most part, so for our current purposes we can treat it as a constant. That aside, I cannot really follow what you are saying so instead of trying to rebut it in detail I will just lay out in a bit more detail how it actually works and challenge you to rebut me:
Force is equal to mass x acceleration (F = ma), therefore a = F/m.

Force due to gravity = strength of gravity x mass (F = mg). This you got right.

Therefore, aceleration due to gravity = mass x strength of gravity divided by mass. Mass, being both on top and bottom of the equation, cancels (a = gm/m = g).

Therefore, acceleration due to gravity (neglecting air resistance) is independant of mass. QED.
TLDR: How fast you fall is (neglecting air resistance) completely independant of mass. Counterintuitive, but true.

Including the effects of air resistance makes things a lot more complicated, but as I understand it does not make much difference to humans (OTOH, unless they are denser than normal living creatures, creatures the size of hamsters are pretty much immune to falling damage).

_
glass.
 

Garthanos

Arcadian Knight
Can be, and is.


g absolutely changes, it just does not change enough to worry about for the most part, so for our current purposes we can treat it as a constant.
Exactly so we ignore it. you were or appeared to be claiming it is changing enough to "cancel" the change in force due to mass... it is not cancelling anything about force. (assuming force of damage from a fall)

That aside, I cannot really follow what you are saying
Your wording indicating that the constant of gravity was somehow countering/cancelling the increased force due to increase in mass. It does not.
Therefore, acceleration due to gravity (neglecting air resistance) is independant of mass. QED.
glass.
This is very much not what you said (if it were i would not dispute it and you can simply consider what you mean not in dispute just how you expressed it)
TLDR: How fast you fall is (neglecting air resistance) completely independant of mass. Counterintuitive, but true.
(also a trivial truth) And you were talking directly about force and how mass increased it but acceleration was cancelling that, ie so now it is a sudden change up and you are claiming the rest of the sentence was about velocity?

However your original statement stated A cancelled the increase in force due to mass by being inversely proportional .... and if you are looking for force (* or subsequently energy which is a better measure) from impact ie falling damage remains increased due to mass it remains higher for larger objects, (yes with g remaining close enough to the same for normal objects etc.)
 
Last edited:

Garthanos

Arcadian Knight
Including the effects of air resistance makes things a lot more complicated, but as I understand it does not make much difference to humans (OTOH, unless they are denser than normal living creatures, creatures the size of hamsters are pretty much immune to falling damage).
Terminal velocity is when the acceleration due to g has been resisted completely by air resistance (you are no longer accelerating -(but get to decelerate from velocity that on impact)

That means our air resistance is not something ignorable
 
Last edited:


glass

(he, him)
However your original statement stated A cancelled the increase in force due to mass by being inversely proportional .... and if you are looking for force (* or subsequently energy which is a better measure) from impact ie falling damage remains increased due to mass it remains higher for larger objects, (yes with g remaining close enough to the same for normal objects etc.)
That was not my "original statement". My original statements were 1) that the mass on both side of the equation cancel, so in vacuo acceleration is independant of mass and 2) that in atmosphere this is technically no longer correct but for falling humans the difference is negliable (not so much for smaller creatures). While I have laid my position out in more detail since, i have never changed it.

Terminal velocity is when the acceleration due to g has been resisted completely by air resistance (you are no longer accelerating
Correct.

Tiny creatures are low enough mass the force of impact is low its not air resistance.
Incorrect. For the reasons now outlined at length, the only reason mass matters at all is due to air resistance.

The direct force of gravity affecting the object at the time of impact is largely irrelevant to falling damage, as can be demonstrated pretty easily: As you yourself correctly stated, F = mg. If m and g are (close enough to) constant, then so is F. If F is the same regardless of whether you fall from 1 ft or 5000 ft, then obviously F cannot directly determined damage.

_
glass.
 

Level Up!

An Advertisement

Advertisement4

Top