Thursday, August 11, 2016

GURPS101: Injury Resistance

In GURPS there are three forms of damage: basic damage, penetrating damage, and injury. Basic damage is the amount rolled on the dice for the attack, penetrating damage is the amount after applying Damage Resistance and other protections (e.g., Injury Tolerance), and injury is the total amount of hit points you suffered from that attack. Seems easy right? Well, it can get complicated when you start adding in exotic protective advantages. But what happens if we start mucking around with that in-between stage that exists in the middle of penetrating damage and injury? Something interesting it turns out.

Theoretically, you could just buy more HP to deal with the splash over injury - but there may be a limit on how much additional HP can be bought in the campaign and there comes a point when more HP doesn't make sense. Kromm posted an interesting new advantage a while back called "Vitality Reserve" (I've since used it and put it into Pyramid because it's a damn useful trait). I've reprinted the text from the link below:
Consider adapting the Energy Reserve idea to HP instead of to FP. A "Vitality Reserve" should do what you want. To fully parallel the behavior of ER, it should be depleted independently of HP, not be subject to the ill effects of HP loss, heal in parallel with HP, and heal irrespective of rest. So VR would amount to HP that you can lose without shock, knockdown, knockout, or death, and that regenerate at the rate of 1 HP/day on a successful HT roll, regardless of conditions. Most of these advantages parallel Ablative DR (which is also independent of HP and not subject to the ill effects of HP loss). Moreover, neither affects what happens in slams and falls. The differences: 
Advantages of Ablative DR:
1. Stops damage, not injury; e.g., 1 point prevents 2 HP of injury from an impaling wound to the torso, 4 HP of injury from a skull hit, etc. 
Advantages of Vitality Reserve:
1. Soaks all injury, including that from disease, poison, and radiation; extreme dehydration and starvation; critical failures that result in direct injury; vampiric leeching; and Cosmic attacks that ignore DR.
2. Can be spent like HP for any ability that allows this, notably spells. 
I'd say that justifies simply pricing VR like HP, much as ER is priced like FP.
So that turns the normal damage progression:
Basic Damage - Damage Resistance = Penetrating Damage x Wound Multiplier = Injury - HP = Total HP lost
Into this:
Basic Damage - Damage Resistance = Penetrating Damage x Wound Multiplier = Injury - VR = Remaining Injury - HP = Total HP lost
Wound Multipliers are things like Injury Tolerance (e.g., Homogenous) and the modifier for damage types (e.g., cutting does 1.5 times damage after accounting for penetration). So what if we added another layer of protection? If you treat Vitality Reserve as something like "Injury Resistance (Ablative, -80%)" then the "cost" to have another layer of protection after Damage Resistance is 10 points a level. So what would it do? Well, its big bonus would be that it stops a point of penetrating damage would can be huge if you have other protective traits such as Injury Tolerance (Damage Reduction) or a high DR. Of course, it may not be a worthwhile purchase at lower levels simply because it's the very last thing you'd calculate before determining total HP loss.

So the damage progression would look something like this:
Basic Damage - Damage Resistance = Penetrating Damage x Wound Multiplier = Injury - VR = Remaining Injury - Injury Resistance = Final Injury - HP = Total HP lost
So a final write-up of "Injury Resistance" would look like this:

Injury Resistance
10 points/level
Your body can take more punishment than is normal. Your have an "Injury Resistance" or "IR" score . Subtract penetrating damage (damage after accounting for any Damage Resistance) from any attack after multiplying the injury for damage type, but before subtracting it from DR. Normal humans cannot purchase IR at all. The GM decides who can purchase this trait, but supers, robots, demons, and the like ought to have access to it. The following Damage Resistance modifiers can be used for this trait as well: Ablative (p. B46), Directional (p. B46), Limited (p. B46), Partial (p. B46), and Semi-Ablative (p. B46). A few special modifiers apply:

Special Enhancements
Wounding Resistance: Reduce the multiplier for damage type by one step per level of this trait when calculating damage: x4, x3.5, x3, x2.5, x2, x1.5, no multiplier, x0.5, x0.25, x0.2, x0.1, x0.05. +20%/level.

Picking Over the Bones
So this came up in a conversation with my friend +Hal Batty after he asked how I'd price a protective trait that subtracted from the total penetrating damage of an attack. It basically snowballed from there. The idea is (I think) sound, it adds some complications for gameplay, but no more than any other protective trait (e.g., Injury Tolerance). It would certainly make the creation of a few archetypes easier. And would be downright useful in a supers campaign. If you use this in game, drop me a line and let me know how it went.


  1. That blue text is rough to read on the black background. :(

    1. A bit, though I'll admit the whole stark white on black plays tricks with my eyes. It's worth at least -2 to Per.

    2. It's highly unlikely I'll ever change the white on black. I'm sorry. That's part of my brand.

    3. I find it much better, and I like white on black, most research finds that it improves readability anyway.