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Thread: [3.5, d20, AD&D] Falling damage

20091022, 07:02 AM (ISO 8601)
 Join Date
 Nov 2005
 Location
 Northamptonshire, UK
[3.5, d20, AD&D] Falling damage
I've never been entirely satisfied with the falling damage system in D&D in any of its incarnations: it's purely linear, but acceleration due to gravity is a square function.
Now I don't want to kill any catgirls with applying physics too rigidly to D&D, but I do have to make a system that uses some kind reality in the mathematical function.
After much examination of terminal velocity data for big and little creatures, skydivers and the like, and looking at the equations for velocity of a falling object (on Earth), and d20's sensible rules for altering damage dice in collisions based on the smallest object in that collision, I've come up with this:
Falling damage = XdYwhere X = (square root of height [rounded down]) 1where Y = die type for your size category
Y starts at d3 for Tiny creatures, and increases by size category.
(Tiny = d3, Small = d4, Medium = d6, Large = d8, Huge = d10, Gargantuan = d12, Colossal = d20)
Fine and diminutive creatures take no damage from falling.
Maximum falling damage is a number of dice equal to the square of your size category.
(Tiny = 3 [squared to 9], Small = 4 [squared to 16], Medium = 5 [squared to 25], Large = 6 [squared to 36], etc)
The rational behind this set of figures?SpoilerVelocity from falling = square root (height fallen * 64) [feet per second]Spoiler
dealing 1 die of damage per 10 fps
~ (square root (Height fallen)) 1Terminal velocity for humans is in the region of 200  300 ft/s
Wind resistance to acceleration from low mass / high surface area creatures, such as diminutive and fine creatures like hamsters and spiders is low enough that they never exceed a few feet per second.
Under this rule, characters are subject to less falling damage from great heights, and slightly more from lower heights.
To avoid high level fighter types jumping off 200ft drops and absorbing the damage as a means of ordinary movement, you run the risk of CON damage from any fall over twice your height.
Roll 1dQ, where Q is the die type closest to the number of dice used to roll damage.
Fortitude save (DC = 10 + number of dice) halves.
PEACH...?
After all the helpful physics lessons, I've come to the conclusion that the linear increaee in damage is the most sensible, realistic and simple method.
 Falling deals XDY damage to Tiny or larger creatures (and diminutive or smaller objects, but not creatures).
 X is number of feet fallen / 5
 Y starts at d3 for Tiny creatures, and increases by size category.
 (Tiny = d3, Small = d4, Medium = d6, Large = d8, Huge = d10, Gargantuan = d12, Colossal = d20)
For numbers of dice over 10, you may wish to use the average damage.
Grant a Tumble (or Dexterity) check to reduce the damage from the fall.
 If the Tumble (or Dexterity) check exceeds DC 5 + number of dice (maximum 50), you take half damage.
 If the Tumble (or Dexterity) check exceeds 10 + 2 * number of dice, no damage is taken.