Damage and Injury

See Injuries for even more details.

Damage and Injury

If your attack roll succeeds and your target fails his defense roll (if any), you may make a damage roll. This tells you how much basic damage you dealt to your target.

Your weapon (and, for muscle-powered weapons, your ST), or your natural or Innate Attack, determines the number of dice you roll for damage. If your target has any Damage Resistance (DR) – from armor, the Damage Resistance advantage, protective magic spells, etc. – he subtracts this from your damage roll.

If your damage roll is less than or equal to your target's effective DR, your attack failed to penetrate – it bounced off or was absorbed. A cutting, crushing, impaling, or piercing attack can sometimes cause damage without penetrating, however; see Flexible Armor and Blunt Trauma.

If your damage roll exceeds your target's DR, the excess is the penetrating damage. If your foe has no DR, the entire damage roll is penetrating damage.

Once you know the penetrating damage of your attack, apply the wounding modifier for damage type (this matters only for cutting, impaling, and certain types of piercing damage). This gives the injury the foe suffers, which is subtracted from his Hit Points.

Example: Your "basic damage" with your sword is 2d+1 cutting. You roll 2 dice, add 1, and do 8 points of basic damage. Your foe has DR 3, so your penetrating damage is 5 points. You then apply the ×1.5 wounding modifier for cutting attacks, resulting in 7 points of injury (always round down). Your foe loses 7 HP.

Damage Roll

Knockback

When you hit someone very hard, you may knock him away from you! This is called "knockback." Only crushing and cutting attacks can cause knockback. A crushing attack can cause knockback regardless of whether it penetrates DR. A cutting attack can cause knockback only if it fails to penetrate DR.

Knockback depends on basic damage rolled before subtracting DR. For every full multiple of the target's ST-2 rolled, move the target one yard away from the attacker. For instance, a man with ST 10 would be knocked back one yard per full 8 points of basic damage. If the target has ST 3 or less, knockback is one yard per point of basic damage! If the target has no ST score at all (like a wall), or is not resisting, use its HP instead.

Anyone who suffers knockback must attempt a roll against the highest of DX, Acrobatics, or Judo. If he is knocked back more than one yard, he rolls at -1 per yard after the first. Perfect Balance gives +4 to this roll. On a failure, he falls down.

If you knock your foe into something solid, the result – including damage to him and whatever he hit – is as if he had collided with it at a speed equal to the yards of knockback. See Collisions and Falls.

"Knockback Only": Some attacks – a jet of water, a shove, etc. – do knockback but no damage. Roll the listed damage and work out knockback as usual, but no actual injury occurs (unless the target collides with something!).

You usually make your own damage rolls, and the GM rolls for NPCs. Damage rolls are expressed as a number of dice, sometimes with a modifier; e.g., "6d-1" or "1d+2." A negative modifier can't reduce damage below 0 if the attack does crushing damage, or below 1 if it does any other type of damage.

High-damage attacks may express damage as a number of dice with a multiplier. For instance, “6d×3” means "roll 6d and multiply the total by 3." If those six dice came up 21, you would do 63 points of damage. This is just a quick way to roll lots of dice.

The result of the damage roll (after any additive or multiplicative modifiers, as explained above) is the hit's "basic damage."

Half Damage (1/2D) for Ranged Weapons

If a ranged weapon has two range statistics, the first is its Half Damage (1/2D) range, in yards. If the target is at or beyond 1/2D range, divide basic damage by 2, rounding down. (This is a simplification! Realistically, most weapons lose striking power gradually as air resistance slows them down, but a detailed calculation would be unplayable.)

Some ranged weapons (e.g., grenades) do not suffer a reduction in damage; these do not list a 1/2D range. The damage of an attack modified with Follow-Up is never halved, either – although its "carrier" attack is subject to 1/2D effects as usual.

Finally, if an attack has a 1/2D range but requires a resistance roll to avoid an affliction of some sort, add +3 to the resistance roll instead of halving damage (if any).

Damage Resistance and Penetration

Damage Resistance (DR) rates the degree of protection that natural or worn armor, a force field, tough skin, etc. affords against damage. Objects and vehicles have their own DR values that protect against any damage they suffer – and if you take cover behind or inside them, their DR also protects you.

Subtract DR from basic damage. The result is the "penetrating damage" that punched through or deformed the armor enough to cause a significant injury. For instance, if you are hit by an attack that inflicts 6 points of basic damage and you're wearing mail with DR 4, you take 2 points of penetrating damage.

In general, DR from multiple sources is additive; e.g., if you have a natural DR of 2 and put on a tactical vest with DR 15, your total DR is 17. Exceptions will always be noted.

The DR of armor often varies by body part. If you are not using the hit location rules (see Hit Location), just assume that any hit strikes the torso, and apply its DR.

Finally, note that DR from certain sources may provide differing degrees of protection against different damage types.

For more on DR, see Damage Resistance and Armor.

Armor Divisors and Penetration Modifiers

An "armor divisor" indicates that an attack is especially good (or bad) at penetrating Damage Resistance. Armor divisors appear on weapon tables as numbers in parentheses after damage dice; e.g., "3d(2) pi" means 3d piercing damage with a (2) armor divisor.

A divisor of (2) or more means that DR protects at reduced value against the attack. Divide the target's DR by the number in parentheses before subtracting it from basic damage; e.g., (2) means DR protects at half value. Round DR down. Minimum DR is 0.

Some divisors are fractions, such as (0.5), (0.2), or (0.1). DR is increased against such attacks: multiply DR by 2 for (0.5), by 5 for (0.2), and by 10 for (0.1). In addition, treat DR 0 (e.g., bare skin) as if it were DR 1 against any fractional armor divisor!

There are several other "penetration modifiers" that affect the protection required to stop a given attack – see Blood Agent, Contact Agent, Follow-Up, Respiratory Agent, and Sense-Based. These are often found on Afflictions and toxic attacks. See Special Penetration Modifiers for details.

Fast Damage Resolution for Multiple Hits

If a rapid-fire attack scores multiple hits, you can speed play as follows: instead of rolling damage per hit, determine damage for one hit, subtract DR, and multiply the resulting penetrating damage (or blunt trauma) by the number of hits.

Flexible Armor and Blunt Trauma

Flexible armor such as a leather jacket, mail hauberk, or a modern ballistic vest is much lighter than rigid armor, but it doesn't absorb the full force of the blows it stops. An attack that does crushing (cr), cutting (cut), impaling (imp), or piercing (pi-, pi, pi+, pi++) damage may inflict "blunt trauma" if it fails to penetrate flexible DR.

For every full 10 points of cutting, impaling, or piercing damage or 5 points of crushing damage stopped by your DR, you suffer 1 HP of injury due to blunt trauma. This is actual injury, not basic damage. There is no wounding multiplier.

If even one point of damage penetrates your flexible DR, however, you do not suffer blunt trauma.

If you layer other DR over flexible DR, only damage that penetrates the outer layer can inflict blunt trauma.

Corrosion

An attack that inflicts corrosion (cor) damage – acids, disintegration beams, etc. – destroys one point of the target's DR per 5 points of basic damage rolled. This affects armor first, then natural DR. This reduces DR against future attacks, not against the attack that burned off the DR! Natural DR lost by living beings heals at the same rate as lost HP.

Overpenetration and Cover

Some attacks are powerful enough to pass right through cover, a shield, or a victim, and damage someone on the other side. It's usually too much trouble to worry about this, but if it becomes important (e.g., shooting through a door, or a bystander behind your target), see Overpenetration.

Hurting Yourself

Any time you strike unarmed (with bare hands, feet, fangs, etc.) and hit a target with DR 3+, you may hurt yourself! For every 5 points of basic damage you roll, you take one point of crushing damage, up to a maximum equal to the DR of the target you hit. Apply this damage to the body part you used to attack, if you are using hit locations. Your own DR protects against this damage. Exception: This rule does not apply if the target's DR has the Tough Skin limitation (see Damage Resistance).

Wounding Modifiers and Injury

Any damage left over after subtracting DR from basic damage is "penetrating damage." If there is any penetrating damage, multiply it by the attack's "wounding modifier." This is a multiplier that depends on damage type:

• Small piercing (pi-): ×0.5.
• Burning (burn), corrosion (cor), crushing (cr), fatigue (fat), piercing (pi), and toxic (tox): ×1 (damage is unchanged).
• Cutting (cut) and large piercing (pi+): ×1.5.
• Impaling (imp) and huge piercing (pi++): ×2.

The damage after this multiplier determines the injury: the HP lost by the target. Round fractions down, but the minimum injury is 1 HP for any attack that penetrates DR at all. Reduce the victim's current HP total by the injury sustained.

Example: Filthy Pierre is struck by an axe, which does cutting damage. His attacker's basic damage roll is 7, but Pierre is wearing DR 2 leather armor, so he suffers 5 points of penetrating damage. Multiplying by 1.5 for cutting damage, Pierre ends up losing 7.5 HP, which rounds to 7 HP – a nasty wound!

Note that blunt trauma injury has no wounding modifier. Where you were hit may further affect the wounding modifier; see Hit Location. The rules above assume a hit to the torso or face.

Effects of Injury

If you are injured, subtract the points of injury from your Hit Points. Usually, you are still in the fight as long as you have positive HP; see General Injury: Lost Hit Points for details. The most important effects are:

• If you have less than 1/3 of your HP remaining, you are reeling from your wounds. Halve your Basic Speed and Move (round up), which also reduces your Dodge.
• If you have zero or fewer HP left, you are hanging onto consciousness through sheer willpower and adrenaline – or are barely holding together, if you're a machine. You must roll vs. HT each turn to avoid falling unconscious. If you pass out, see Recovering from Unconsciousness for how long it will take to recover.
• If you go to fully negative HP (for instance, -10 if you have 10 HP), you risk death! You must make an immediate HT roll to avoid dying. You must make another HT roll to avoid death each time you lose an extra multiple of your HP – that is, at -2×HP, -3×HP, and so on. If you reach -5×HP, you die automatically. See Death.

The sudden loss of HP can have additional effects:

Shock: Any injury that causes a loss of HP also causes "shock." Shock is a penalty to DX, IQ, and skills based on those attributes on your next turn (only). This is -1 per HP lost unless you have 20 or more HP, in which case it is -1 per (HP/10) lost, rounded down. The shock penalty cannot exceed -4, no matter how much injury you suffer.

Major Wounds: Any single injury that inflicts a wound in excess of 1/2 your HP is a major wound. For a major wound to the torso, you must make a HT roll. Failure means you're stunned and knocked down; failure by 5+ means you pass out. For details, see Major Wounds and Knockdown and Stunning.

Stunning: If you're stunned, you are -4 to active defenses and cannot retreat, and must Do Nothing on your next turn. At the end of your turn, attempt a HT roll to recover. If you fail, you're still stunned and must Do Nothing for another turn. And so on.

For more about injuries – and how to recover from them! – see Injuries.

Injury to Unliving, Homogenous, and Diffuse Targets

The Wounding Modifiers and Injury rules assume a human, animal, or other ordinary living being. Machines, corporeal undead, swarms, and other unusual entities are much less vulnerable to certain damage types:

Unliving: Machines and anyone with Injury Tolerance (Unliving), such as most corporeal undead, are less vulnerable to impaling and piercing damage. This gives impaling and huge piercing a wounding modifier of ×1; large piercing, ×1/2; piercing, ×1/3; and small piercing, ×1/5.

Homogenous: Things that lack vulnerable internal parts or mechanisms – such as uniformly solid or hollow objects (e.g., melee weapons, shields, and furniture), unpowered vehicles, trees, and walls – are even less vulnerable! This includes animated statues, blobs, and anything else with Injury Tolerance (Homogenous). Impaling and huge piercing have a wounding modifier of ×1/2; large piercing, ×1/3; piercing, ×1/5; and small piercing, ×1/10.

Diffuse: A target with Injury Tolerance (Diffuse) is even harder to damage! This includes swarms, air elementals, nets, etc. Impaling and piercing attacks (of any size) never do more than 1 HP of injury, regardless of penetrating damage! Other attacks can never do more than 2 HP of injury. Exception: Area-effect, cone, and explosion attacks cause normal injury.

Example: Edmund Zhang empties his 9mm machine pistol (2d+2 pi damage) at an approaching zombie. He hits three times. After subtracting the zombie's DR 1, he scores 8 points of penetrating damage with the first bullet, 7 with the second, and 10 with the third. The zombie has Injury Tolerance (Unliving), so the usual ×1 wounding modifier for piercing damage drops to ×1/3. Rounding down, the three bullets inflict 2 HP, 2 HP, and 3 HP of injury. The zombie had 24 HP, so it has 17 HP left. Undaunted, it shambles forward. Edmund should have brought an axe or a flamethrower!

Special Damage

Attacks Without Damage

Not all attacks inflict damage. Some – stun rays, drugs, etc. – offer a modified HT roll to resist (e.g., HT-2). If the victim is hit and fails his HT roll, he's affected; see Affliction for details. Other attacks restrain the victim, requiring ST rolls to break free; see Binding.

Certain attacks have "special effects": poison, electrical shocks, stunning, setting the victim on fire, etc. See the weapon tables, specific attack enhancements, and other relevant sections of GURPS.

Follow-Up Damage

Some attacks, such as poison darts and exploding bullets, have "follow-up" damage: a second type of damage that occurs an instant after the primary effect. The primary effect is always ordinary damage of some type – piercing, impaling, etc.

If the primary damage penetrates the target's DR, the follow-up effect occurs inside the target. DR has no effect! Follow-up effects that occur internally never inflict knockback or blunt trauma – even if their damage type usually does.

If the primary damage fails to penetrate DR, the follow-up effect occurs outside the target, if appropriate, as if the target had been touched – just like a linked effect (see below). Thus, poison that must enter the bloodstream would have no effect if the arrow that carried it failed to penetrate. On the other hand, an explosive projectile would still do damage ... but the DR that stopped the primary damage would protect against it.

Linked Effects

Some attacks have a linked effect. This is a second type of damage or other effect that occurs simultaneously with the primary effect. Make one roll to hit, but resolve all damage and resistance rolls separately for the primary effect and the linked effect. An example of a linked effect is a grenade that inflicts both a crushing explosion and a blinding flash of light on detonation. A person in armor might be blinded but unhurt, while an unarmored person with eye protection might be wounded but not blinded.