Realistic Human DR

[Pursuivant]

Both Martial Arts options are bordering on cinematic, but could have realistic explanations. Tough Skin is more likely than Ablative.

If you want hyper-realism:

Nominally the human skull provides DR 2 for the brain but that's perhaps a bit cinematic as well, since living bone isn't as rigid as dry bone and any injury which hits the head hard enough to inflict HP damage as the potential to inflict Traumatic Brain Injury (TBI). At best, it provides DR 1 vs. kinetic attacks (cr, cut, imp, pi), DR 2 vs. burn and corrosive attacks.

The human rib cage should provide DR 1 (Ablative, Limited (Only vs. crush, cut, burn & corrosive) for the Vitals.

The spine should provide DR 2 to protect itself (Ablative, Limited: Only vs. crush, cut, burn & corrosive).

Fat, thick muscle, scar tissue, or similar might give DR 1 (Tough Skin, Limited: Crushing only, Not for Head or Groin).

Realistically, people who play contact sports do suffer massive bruising, it's just that it doesn't immediately show. The same thing is true of normal people who suffer massive crush trauma. The damaging effects of the injury don't really kick in until after the wound begins to heal, when all the crushed, dead tissues starts to be broken down. At that point, the massive increase in waste products in the blood stream can overload the kidneys.

That suggests a potential modifier for DR:

Delayed Damage Onset (-20%): Your DR doesn't actually protect you, it just prevents damage from affecting you as quickly. If you take this limitation, keep track of all points of damage you suffer. At some point in the future, specified when you take this limitation you suffer all the deferred damage at once. Choose any delay from 1 hour to 1 week (although 24 hours is most common). Deferred damage might be due to supernatural or superscience effects or just the fact that your body doesn't respond to the damage as quickly. This limitation is commonly associated with the Ablative or Tough Skin limitations.

[kirbwarrior]

Originally Posted by Pursuivant

Nominally the human skull provides DR 2 for the brain but that's perhaps a bit cinematic as well, since living bone isn't as rigid as dry bone and any injury which hits the head hard enough to inflict HP damage as the potential to inflict Traumatic Brain Injury (TBI). At best, it provides DR 1 vs. kinetic attacks (cr, cut, imp, pi), DR 2 vs. burn and corrosive attacks.

I'm not even sure it would actually count as any DR. In more realistic campaigns another GM friend ruled that if you take 1 or 2 damage to the skull, it doesn't count as hitting the brain but any damage past that does count instead of the skull providing DR. That might be a little overly fragile, though.

[Johnny1A.2]

Originally Posted by kirbwarrior

I'm not even sure it would actually count as any DR. In more realistic campaigns another GM friend ruled that if you take 1 or 2 damage to the skull, it doesn't count as hitting the brain but any damage past that does count instead of the skull providing DR. That might be a little overly fragile, though.

One problem with realistically modeling human (and animal) damage tolerance is that in real life, it's all over the place. There are so many factors in play that lots of outcomes are possible. People are fragile. That's a fact of life. Yet they sometimes survive, relatively intact and unhurt, the most amazing things that really, logically, should have crippled or killed them. At the same time, relatively minor impacts and injuries are sometimes known to be crippling or lethal if things go badly. You can find examples of all sorts of things from real life.

That said, the general rule in real life is that people are fragile, and real violence and real disaster can rapidly cripple or kill you, no matter how much of a badass you are.

[Polydamas]

Originally Posted by Johnny1A.2

One problem with realistically modeling human (and animal) damage tolerance is that in real life, it's all over the place. There are so many factors in play that lots of outcomes are possible. People are fragile. That's a fact of life. Yet they sometimes survive, relatively intact and unhurt, the most amazing things that really, logically, should have crippled or killed them. At the same time, relatively minor impacts and injuries are sometimes known to be crippling or lethal if things go badly. You can find examples of all sorts of things from real life.

To reinforce that, some informed people think that GURPS armour performance is too unpredictable, but I don't know anyone who thinks that the wounding rules are unrealistically unpredictable. Life is full of cases like the person who died from one punch or the person who was shot in the head with a .22 and the bullet was channelled between scalp and skull rather than inflicting a traumatic brain injury.

[Anthony]

Originally Posted by Polydamas

To reinforce that, some informed people think that GURPS armour performance is too unpredictable, but I don't know anyone who thinks that the wounding rules are unrealistically unpredictable.

GURPS performance against armor is simultaneously too predictable and too unpredictable. Whether an attack penetrates a given thickness of armor plate is pretty predictable. How much armor plate is actually in front of an attack is not.

[Pursuivant]

Originally Posted by Anthony

GURPS performance against armor is simultaneously too predictable and too unpredictable. Whether an attack penetrates a given thickness of armor plate is pretty predictable. How much armor plate is actually in front of an attack is not.

Base HP damage isn't just raw kinetic energy, it's also the exact angle and location where that energy is delivered, relative motion of attacker and defender, and a bunch of other little things. A low dice roll for damage means a glancing blow or a blow which strikes the thickest part of DR at an unfavorable angle. A high roll means a "partial critical hit" which strikes armor in a weak spot or at just the right angle to penetrate.

Realistically, unless the attack is truly massive, armor is going to turn impaling, cutting, or piercing damage into crushing damage. There's an option to do just that in one of the GURPS Low Tech books.

Even more realistically, damage for various weapons should be given an averaged HP dice value with +/-10-20% above or below that. That's easily modeled by rolling 1d instead of the usual damage dice, with 1: -20%, 2: -10%, 3-4 no modifier, 5: +10%, 6: +20%.

I'm not sure your average player would tolerate not being able to roll dice for damage, however! Roll to hit/dmg. is one of the oldest and most satisfying RPG mechanics there is.