seasong.idempot.net

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Damage is measured in two ways: wound severity and overall system trauma.

Wound Severity
This is primarily a descriptive system, and is largely what attracted me to Vicious in the first place.

Wound severity follows the scale below:
Very Slight: bruise, nasty scratch, first degree burns
Slight: bone-deep bruise, light cut, second degree burns, a bullet that penetrated an inch or two
Minor: fractured small bone (such as a finger), cut, third degree burns, a bullet that penetrated deep into the body or expanded an inch in
Moderate: broken small bone, fractured medium bone (wrist), deep gash, severed hand, charcoal skin, a bullet that punched through the body or expanded deep in the body
Major: shattered small bone, broken medium bone, fractured large bone (thigh), severed limb, cooked, a bullet that expanded and still managed to punch through the body
Massive: shattered medium bone, shattered ribs, broken large bone, severed torso, well done roast
Very Massive: Shattered large bone, vertically split torso, charcoal

I've also used Damage Points to measure the above scale: 1 DP is a Very Slight wound severity, and each doubling of DP moves one step up. The main reason for DP is for purposes of calculating the damage done in real world terms: the base damage of a weapon in DP is equal to (joules of energy/10)^(1/2). Weapons have different efficiencies of translating that raw energy, but that's a good starting point.

My next post will handle ways to determine how much damage a particular attack does.

Trauma

Characters should have a competency number for their "toughness". Any time a shock roll is required, this is what is rolled against.

A person can go into shock any time they suffer a wound. A Very Slight wound severity gives a +6 to the roll, and each step worse gives a -2. A wound which penetrates the body (such as a cut or bullet wound) gives an additional -2.

Any time it is possible to go into shock, make a shock roll at the above bonus or penalty. If you fail, you increase one level in shock, and roll again. If you succeed, nothing bad happens. It is possible to take a Slight wound from a bullet to the foot, and go into shock and die, but not very likely.

There are numerous other things which can also cause shock rolls. A bolt of lightning, the sudden trauma of dropping into freezing cold water, and bleeding to death

Example: Bleeding to Death: If you are bleeding enough to matter, you make a shock roll after 15 seconds at +6, 30 seconds at +4, 1 minute at +2, 2 minutes at +0, 4 minutes at -2, 8 minutes at -4, 15 minutes at -6, 30 minutes at -8, and so on. This assumes that you haven't managed to stabilize and stop bleeding.

The shock levels are:
Healthy: Yay!
Mild Shock: -1 to all rolls (except shock rolls)
Shock: -2 to all rolls (except shock rolls)
Deep Shock: -4 to all rolls (except shock rolls), 1/2 movement speed
Unconscious/Coma: Exactly that
Dead: Exactly that

If you jump directly to Dead (skipping Unconscious/Coma), you fall unconscious for a reasonable amount of time.
_________________
-thomas

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Rolling Damage

When I ran Vicious myself, and mostly in my head, it was "good enough" to simply have a conversion rate for energy, and some slight modifiers for the direction and type of wound. The basic principles of the system were in my head, and I would just work from that.

For a system usable by someone else, thicker guidelines are needed. I've done a bunch of those in the past, and they have generally resulted in bad results at this or that extreme. This is yet another attempt.

Firstly, let's talk about damage type. In Vicious, most non-systemic damage to the body can be defined as:
- impact blunt trauma (bruises, broken bones)
- torsion/stretch trauma (twisted ankle, head being pulled off)
- two-dimensional cut (most knife slashes, cutting off an arm)
- one-dimensional cut (armor piercing bullets, arrows, needles)
- hamburger "cut" (abrasions, expanding bullets)
- localized cellular destruction (burning, acid, necrotic toxins)

You can break those down further, but for purposes of Vicious, those plus the wound severity are generally sufficient.

Note to self: I need to post a cross-reference between those damage types and wound severity.

In absolute terms, the energy of an attack, modified by its cross-section, determines the absolute maximum amount of damage it can do. Realistically, it should never do more damage than this ever, except in cinematic realities where "joules" are something you steal from the King.

It also shouldn't do that much damage very often; usually, assuming a reasonably skilled person, it should do a step below that. On near-misses, it should also do a "graze".

In the past (when I used DP more explicitly), I would roll 1d10 x 10%, and that was the percentage of the maximum damage that was done. While that worked pretty well for me, most people don't like figuring out 60% of 8 on the fly .

Another way to handle it is as an aspect of skill: a success on an attack roll by 0 results in doing damage three steps below the maximum; by 1-2 is two steps below; by 3-5 is one step below; and by 6+ is the maximum damage. If combat is a contested roll, then the other person's successes would reduce yours.

I'm liking this method, but I haven't yet tested it thoroughly.
_________________
-thomas

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Damage types, mit naming!

Bludgeoning - impact blunt trauma (bruises, broken bones)
Cutting - two-dimensional cut (most knife slashes, cutting off an arm)
Impaling - one-dimensional cut (armor piercing bullets, arrows, needles)
Stretching - torsion/stretch trauma (twisted ankle, head being pulled off)
Rending - hamburger "cut" (abrasions, expanding bullets)
Annihilating - localized cellular destruction (burning, acid, necrotic toxins)

It might be worth breaking Annihilating down into Burning, Corroding and Poisoning?
_________________
-thomas

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A kinetic attack can transfer momentum into an opponent or can penetrate into the body at a specific location. Momentum damage is primarily useful for shaking an opponent up, knocking him out (by changing the velocity of his skull relative to his brain), or shoving him back. Penetration is primarily useful for doing localized damage, such as breaking bones, crushing the throat, or bruising muscles.

For penetration, any given material will have a toughness index. For the purposes of this discussion, human flesh has a toughness index of 1. The depth of a penetrating attack is 1cm for 1 joule. The joules required to penetrate deeper goes up with the centimeters squared (so to penetrate 2cm needs 4 joules; to penetrate 10cm needs 100 joules). The energy of the attack is divided by the surface area of the attack, in cm².

In addition to penetration is momentum. The more momentum an attack delivers, the less of its energy can go into penetration. Or to put that another way, the penetration ablates the energy of the attack and reduces the delivered momentum.

A bullet tends to impart little of its energy into momentum. A slow-moving truck tends to impart little of its energy into penetration.

Generally, speaking, we can divide attacks into three types: penetrating, mixed, and shoving.

A penetrating attack has exceeded the flex threshold of the target material, and virtually all of the momentum is lost to the ablation of the material.

A shoving attack is below the ablation threshold of the target material, and does virtually no damage but delivers almost all of its momentum.

A mixed attack (almost all attacks) is somewhere in the middle.
_________________
-thomas

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Last edited by seasong on Tue Jan 25, 2005 7:19 pm; edited 2 times in total

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Penetration and "Damage"
In order to actually penetrate, there are several factors standing in the way of an impact.

Glancing Blows
The first is the very likely possibility of a glancing blow. The human body is round in most locations, which means that only a few directions of impact are actually going to deliver maximum energy. The probability of hitting a "sweet" spot varies wildly by body location and the skill of the puncher, but we can abstract it to a 10% chance for an untrained attacker in Vicious (10% can be represented any number of ways: 10 on a 1d10 roll; success by 4 or more on a competency check; or a die roll which yields the maximum damage 10% of the time). The chance of a severely glancing blow is roughly the same. Everything else (that is an actual hit) will tend to be somewhere in the middle.

Momentum Transfer
As the punch begins to penetrate, the object being punched begins to move away, reducing the transfer of the punch's remaining energy. The faster the energy transfer, the less energy loss, and the less actual change in momentum the target undergoes (because the energy was translated into damage and heat rather than momentum).

For purposes of Vicious, this will be strongly abstracted. Roughly, we can classify a kinetic impact as: fast, medium, slow. A fast impact transfers 100% of its energy as damage (this is incorrect, but even a 10% energy loss will not affect Vicious at a level of granularity that is useful). A medium impact transfers 50% of its energy as damage. A slow impact transfers 0% of its energy as damage (and is better known as a shove or push).

Deformation & "Flex"
Generally speaking, the more energy delivered at contact, the less ability the muscles have to flex and squish. Flexing and squishing reduce the damage done to any particular piece of the muscle, but spread the damage over a larger area.

If the damage to a particular area is reduced below the bruising threshold, no damage at all is done - the muscle managed to remain within its safe parameters for deforming.

The same applies to any material, even bone and concrete.

In game terms, this will not mean much, other than that it would be good to be able to represent the ability of the body to absorb a certain amount of impact without harm (in practice, a penetration depth which is less than 10% of the muscle's depth is probably about right).

So what is damage?
When the transfer of energy overcomes momentum loss, the underlying object ablates: blood vessels rupture, strands of muscle snap apart, skin and fatty tissue splits, and bones break.

When it does not, the underlying object is knocked back. In the case of a flexible object like the human body, it is knocked back segment by segment. As each segment jerks the next segment along with it, the secondary impact between those segments generates some additional ablation (but which is more generalized than damage to specific locations). When the brain is ablated by the inside of the skull, you often have a knockout.

In Vicious, direct ablation is handled by DP (damage points). Indirect ablation is handled by SC (shock capacity) and shock rolls (to test for going into shock, being knocked unconscious, and so on).

REAL Penetration
A side note is this: at what point does penetration depth overcome the flexibility of the skin and break through to impart its energy to the insides of the body directly?

An exact measure is hard to give, but does not appear to be much - perhaps as little as 100+ joules per cm². This is roughly equivalent to a 300mph baseball (although it should be noted that the baseball will more likely ablate itself on impact, reducing the likelihood of penetration).

There is also some anecdotal evidence that some individuals suffer penetration and skin breakage at significantly higher or lower energy amounts than others.

Toughness Index
Some basic toughness index numbers.

Most flesh: 1
Bone: 10-16 (depending on what source you believe)
_________________
-thomas

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Last edited by seasong on Tue Jan 25, 2005 7:55 pm; edited 1 time in total