But is it really the sudden stop?

[RyanW]

At least some fall damage is due to sudden deceleration, but some of it is also the fact that the bits that hit the ground stop while the bits above them try to keep going.

If, by magic or technology, you could stop a fall instantly by stopping every part of a person simultaneously, how much would that reduce fall damage?

[sir_pudding]

That would use the rules for Acceleration rather than Collisions. Assuming a spread eagled fall at 60 yards per second you would need to make a HT-2 roll (-4 for 6G; +2 for position) and lose 1 FP per margin of failure and black out on a critical failure (although in this case you would actually red out).

[acrosome]

Well, if you sort of magically remove all kinetic energy from every individual molecule at the moment of impact then theoretically you would take no damage whatsoever.

Except that you'd also be frozen solid.

And then shatter from thermal shock.

Very messy.

[Armin]

But what if you didn't remove all kinetic energy; just that along the falling vector. I think that's what RyanW is actually asking about.

There shouldn't be any freezing, then. And you shouldn't red or black out, because all your blood is still doing exactly what it ought to, right? And there's no brain smashing against skull, no other internal collisions or malformations. Are there really any issues if you could magically catch someone like that?

[sir_pudding]

Originally Posted by Armin

But what if you didn't remove all kinetic energy; just that along the falling vector. I think that's what RyanW is actually asking about.

There shouldn't be any freezing, then. And you shouldn't red or black out, because all your blood is still doing exactly what it ought to, right? And there's no brain smashing against skull, no other internal collisions or malformations. Are there really any issues if you could magically catch someone like that?

No, because there would be no difference between that and just teleporting to the ground.

I don't think that the OP meant that though.

[Anthony]

Originally Posted by RyanW

If, by magic or technology, you could stop a fall instantly by stopping every part of a person simultaneously, how much would that reduce fall damage?

To zero. The damage is all from different parts of the body decelerating at different rates.

[Flyndaran]

From falling you almost always hit with some body part first which takes the most damage. Hitting everywhere instantly would change the impact to full body.
I think this would result in the common gaming aspect of generic Hit Point loss.

[Culture20]

Does the impact still matter (absent organs sloshing around inside)? If so, you might model the fall as a slam versus DR of whatever the ground is, and apply “hurting yourself” damage as if you slammed into a dirt/concrete/steel wall, not unlike punching a knight’s breastplate.

[Maz]

It's certainly a popular trick in fiction. You very often see telekinetic used like this, less often also magic. And in those situations, it always result in "no harm done at all".


In fact I would probably assume this to be the default in a supers game. Ie. if someone falls, if I have enough TK to levitate them, I could catch them with no harm. The problem would be noticing and reacting quick enough. And having the TK-lifting power to do so. Maybe set up some inverse calculating for how fast you can slow someone down if you only have enough TK to carry them at Extra-Heavy encumbrance. So if you are at Extra-Heavy you slow them down only 20% per sec (so taking 5 sec total). While at "No enc" you can do it instantly. ... just a very rough guide.

[whswhs]

Originally Posted by Culture20

Does the impact still matter (absent organs sloshing around inside)? If so, you might model the fall as a slam versus DR of whatever the ground is, and apply “hurting yourself” damage as if you slammed into a dirt/concrete/steel wall, not unlike punching a knight’s breastplate.

You have to distinguish two different cases. In one, the upward acceleration is applied evenly over the entire lower surface of the body. In the other, it's applied evenly throughout the entire volume of the body. These have different effects.

In the latter case, the whole body slows down and stops, all at once. Depending on how fast it's going, this may involve an acceleration equivalent to extremely high gravitational force. But it won't cause direct trauma.

But in the former case, the bottom surface stops, and the interior of the body effectively slams into it at high speed. That could cause direct trauma, by compressing the leading surface of the body, as if a shock wave had hit it.

I think the OP was talking about the latter case.