Scaling falling damage to size?

[harpy]

Whether it is 3.5, Pathfinder or 4E all of these systems have fixed damage dice for falling, 1d6 per 10 feet for 3.5/PF or 1d10 per 10 feet for 4E.

It's fine and simple. It assumes that PCs are medium or small creatures and so their mass is close enough that when they fall they take an amount of damage that is fairly comparable. The rules are really intended to see what happens to PCs most of the time, rather than seeing what happens when bigger or small creatures fall.

However, when it comes to weapons then the "physics engine" kicks in a bit more (Force x Mass = Momentum) and suddenly the mass of the weapon becomes important, and so we have die steps keyed to the size of the creature. It's a bit more fussy and detailed, but since the main point of D&D is to conduct combat then this level of granularity is generally desired.

Now if you wanted to extend the physics engine a bit more and didn't mind that extra little bit of information to keep track of it seems rather simple and realistic to key falling damage to die steps based on size. Something like:

3.5/PF

Fine 1
Diminutive 1d2
Tiny 1d3
Small 1d4
Medium 1d6
Large 1d8
Huge 1d10
Gargantuan 1d12
Colossal 2d6

4E

Fine 1d2 (I think they got rid of this size?)
Diminutive 1d3
Tiny 1d4
Small 1d6
Medium 1d10
Large 1d12
Huge 2d6
Gargantuan 2d8
Colossal 3d6


Does this sound right? Or at least not game breaking?

 

[Celebrim]

Probably this is best discussed in the appropriate house rules section, but yes, falling damage in theory ought to scale to size.

The way I do it is simplier than what you suggest. I simply add the creatures size modifier to each die throw, and I think that this is the easiest way to modify the default system.

So, using that house rule each 10' the creature fell would do:

1d6-8 (0!) damage to a fine creature
1d6-4 (0-2, avg. .5) damage to a diminutive creature
1d6-2 (0-4, avg. 1 2/3) damage to a tiny creature
1d6-1 damage to a small creature
1d6 damage to a medium creature
1d6+1 damage to a large creature
....

And so forth. If you wanted to go even further, the maximum dice worth of damage would also scale with size. So, if falling damage was limited to 20 dice for a medium creature, a diminutive creature might at most take 3 dice. Realistically speaking, mice almost can't die as the result of falling because their terminal velocity is too low.

Before adopting this, I think you should take steps to balance small creatures with bigger ones. Being small already represents a pretty significant advantage in D20, and this just extends that if used in isolation.

 

[Mustrum_Ridcully]

Probably this is best discussed in the appropriate house rules section, but yes, falling damage in theory ought to scale to size.

The way I do it is simplier than what you suggest. I simply add the creatures size modifier to each die throw, and I think that this is the easiest way to modify the default system.

In 3E that works, 4E has no size modifiers.

Though you could certainly add a straight +1/-1 modifier for every size category different from medium or so.

 

[Umbran]

However, when it comes to weapons then the "physics engine" kicks in a bit more (Force x Mass = Momentum)

Nitpick - if you are going to invoke physics, it pays to get it right. Mass x Velocity = Momentum. Velocity is not Force.

Does this sound right? Or at least not game breaking?

Well.. how often do big or small things fall in your game? My personal experience is that falling is a rare event - even if it wasn't particularly balanced, it probably isn't going to harm much if it is infrequent.

 

[Goken100]

How about multiplying the damage for every square that the creature takes up? This doesn't address tiny stuff, but no biggie. Nobody pushes anything smaller than a "small" creature off a cliff anyways.

While this might seem like a lot of damage, also keep in mind how difficult it is to push bigger creatures into pits and off cliffs. Every single square has to be over the hole. If the whole thing looses footing... boom! 4d10 x distance fallen!

On second thought that would be a bit much. Maybe just x2 for large, x3 for huge, etc. The multiplier would be the circumference.