Sunday, November 15, 2015

A more coherent to-hit & damage system

This post builds upon this last one.  The combat system I threw out there was somewhat "off the top of my head."  This one is a bit more thought out.

In this system, the general procedure for "to hits" is:

  1. Determine if the attack hit the target.
  2. Determine where the attack hit the target (optional in some cases).
  3. Determine if the attack's Damage meets or exceeds the target's Soak.
    1. If so, then then the target is staggered.
    2. If so, and if the target was already staggered, it takes a wound.
    3. If the Damage does not exceed the Soak then there is no effect.
STEP ONE:  DETERMINE IF THE ATTACK HITS THE TARGET

This is a "to hit" roll.
  • D20 Attacker:  Attacker rolls 1d20+Standard Attack modifiers
  • D20 Defender:  TN 10 + Dexterity Bonus + Shield Bonus + other Misc Modifiers (notice:  no armor here!)
  • D6 "Septimus" Attacker:  Attack rolls xd6+Savvy, where "x" equals their skill ranks in Martial Arts and Savvy equals their modifier (+2 to -2) for that ability score
  • D6 "Septimus" Defender:  Use Defender's Dodge score.  Typically "Dodge" is equal to 2+1/2 Martial Arts skill ranks+Savvy Modifier.  High encumbrance (typically caused by hearing heavy armors) can penalize Dodge.
If the attacker meets or exceeds the defender's target number, then proceed to step two.  If not, then the attack misses completely.

Sidebar:  Encumbrance and Dodge Effects
  • Load capacity = 4+/-Stamina measured in "stones" (~15 lbs)
  • < x1 Load:  12" move, -0 to Dodge
  • < x2 Load:  9" move, -1 to Dodge
  • < x3 Load:  6" move, -2 to Dodge
  • < x4 Load:  3" move, -3 to Dodge
  • < x5 Load:  1" move, -4 to dodge


STEP TWO:  DETERMINE WHERE THE ATTACK HITS

Roll 1d6 and compare to the following table to determine the hit location and any effects that will occur if the Soak is exceeded in step 3.
  • 1:  Legs -- Target lower extremity armor (greaves, etc).  Instead of inflicting a Wound, attacker may opt to Cripple victim.  Cripple = drop prone, unable to move.  Penalty persists until target is no longer Staggered.
  • 2-3:  Torso -- Target torso armor (breastplates, jacks, etc).  No special effects.
  • 4:  Arms -- Target arm armor (gauntlets, bracers, etc).  Instead of inflicting a Wound, attacker may opt to Disarm victim.  Disarm = drop all carried items, unable to manipulate objects until no longer Staggered.
  • 5:  Head -- Target head armor.  Instead of inflicting a Wound, attacker may opt to Disorient victim.  Disoriented victims have a -1 penalty to throw off the Staggered condition.
  • 6:  Critical Hit -- Found a chink in the armor!  Ignore Armor Soak except for that from natural "Stamina."
Special:  For non-humanoids, build or modify the special table.  Typically, 5 is always a "head" shot if the creature has a head, and 6 is always a critical.

Special:  Targets who don't have names (i.e. "mooks") typically wear uniform armor all over and can take only one wound before being incapacitated.  Against mooks who have no, light, or medium armor, skip this entire procedure.  If a mook is wearing heavy plate mail then this procedure may be necessary to allow attackers to find chinks in armor.  Mooks in plate armor are rare in most settings.

Special:  Sometimes players want to make a "called shot."  In that case, they must declare a desire to do so prior to attacking.  The called shot will hit the arms, legs, head, torso, or a chink in the armor as the player desires.  Impose a -1 penalty (D6 Septimus) or -4 penalty (D20) to the "to hit" roll for called shots targeting anything other than the Torso.

Rationale: This table is needed for two primary reasons:
  1. As you'll see with the Soak numbers of armor, most light weapons have no way to penetrate heavier armors.  Historically, this was dealt with by finding chinks in the armor, or targeting unarmored body parts.
  2. A desire to have an option for mix-and-match armor parts (less compelling).
If I could find a good way around problem #1 I would ditch this step in the name of simplicity.

STEP THREE:  DETERMINE DAMAGE AND COMPARE TO SOAK

This is a damage roll.

Damage:  Most weapons deal 1d6 damage modified by the attacker's strength and weigh 1/3 of a stone.
  • Two handed weapons to include heavy war bows deal 1d6+1 damage and all strength modifiers are doubled.  They weigh 1 stone.
  • Light weapons deal 1d6-1 damage.  They weigh 1/6 of a stone.
  • Bows deal 1d6 damage at point blank range, 1d6-1 damage at 200 yards, and 1d3 damage at 300 yards.
    • Heavy bows deal +1 damage at all ranges (and double strength modifier as 2H weapons)
    • Light bows deal -1 damage at all ranges.
  • Early modern black powder long guns (muskets) deal 1d6+16 damage (yes, 16) at the muzzle with no strength modifiers.  They deal 1d6+8 damage at 25+ yards, 1d6 at 50+ yards, and 1d3 at 100+ yards, and 1d2 at 150 yards.
  • Early modern black powder pistols ("handgonnes") deal 1d6+4 damage at the muzzle, 1d6+2 at 25+ yards, and 1d6 at 50+ yards.
  • Ranged weapons deal less damage at range:  Point Blank (full damage), 25 Yards (
Soak:  "Soak" is primarily based on a defender's armor, modified by their Stamina modifier.  These values should be pre-recorded and noted on the character sheet.  As mentioned above, "mooks" wear uniform armor and have only one "soak" value.  Special characters or monsters may have different soaks over different parts of their body.
  • Padded Armors:  Soak 1 (may be worn underneath and add to any other armor's soak; weighs 1 stone)
  • Leather:  Soak 1 (Weighs 1 Stone)
  • Light Plate:  Soak 2 (Weighs 3 Stone)
  • Chain:  Soak 3 (Weighs 2 Stone)
  • Standard Plate:  Soak 6 (Weighs 4 Stone)
  • Heavy Plate:  Soak 12 (Weighs 6 Stone)
Example:  Conan has great stamina (+2) and prefers to wear a standard steel breastplate over a padded jack.  He wears leather greaves and bracers, and dons a mail coif as a helm.  His Soak is:
  • Torso:  8 (6 steel plate + 1 padded + 2 stamina)
  • Legs:  3 (1 leather + 2 stamina)
  • Arms:  3 (1 leather + 2 stamina)
  • Head:  5 (3 mail + 2 stamina)
  • Critical Hits: 2 (0 + 2 stamina)
Example:  Joe Blow the Redshirt pro is an elite foot soldier.  He is equipped with a chain mail ensemble by his liege lord over a padded jack.  His soak is 4 (3 mail + 1 padded + 0 stamina).  There is no need to roll hit locations on him (which speeds combat) as his soak is always 4.

Compare:  Treat the soak as a Target Number for the damage roll.  If the damage roll meets or exceeds the Soak Target Number then the attack deals damage.
  • If the target is already staggered, then a wound is inflicted.
  • If the target is not staggered, then the target is staggered.
"Staggered:"  A creature which is staggered may move at 1/2 speed and suffers a -2 penalty on all checks.  As a full action, the creature can roll a skill check (Martial Arts + Stamina, minus the -2 penalty) against TN 5.  This attempt counts as the character's action for the round.  Success removes the staggered condition.  Failure indicates the creature remains staggered.  Staggered creatures return to normal after a scene is over (assuming they eventually make their check).

"Wounds:"  Most characters can take a number of wounds equal to 2 + 1/2 Martial Skill + Stamina.
  • A character whose wound track is full suffers a -1 penalty on all actions.
  • A character whose wound track is full and who is also staggered is incapacitated.  This means they have been knocked out and are out of the scene.  An incapacitated character may be slain by any foe with a weapon, and is at the mercy of the victors.
  • Mooks (like Joe Blow, the Red Shirt Pro we introduced earlier) have only one wound.
Massive Damage:   Most strikes only inflict either a staggered condition or a wound.  If the damage roll exceeds the soak by 5, then an extra wound is inflicted.  This massive damage threshold can also be precalculated and written on character sheets.

Example:  Joe Blow the Redshirt pro has Soak 4 from his mail armor over padded jack.  Conan hits him with a two handed greatsword.  Conan has great strength (+2 modifier).  He rolls 1d6+1 for the sword; rolling maximum damage, his player shouts "7 damage!"  The GM reminds Conan's player to add double his strength bonus (+2x2) for a total of 11 damage.  This exceeds Joe Blow's Soak of 4 by seven!  Joe Blow is staggered and then suffers an extra wound, taking him instantly out of the fight.

System Note:  Massive damage can occur against unarmored characters occasionally using any one-handed or two-handed weapon.  If targets have just medium armor like Joe Blow above (Soak of 3 or 4), then massive damage will typically only be inflicted by those with above-average strength wielding two handed weapons or on a critical hit which ignores Soak.

SIMPLER ALTERNATIVE

For those who dislike tracking hit locations and different types of armor, this alternative is provided as a faster, simpler option.
  • Do not check for hit location.
  • All characters have uniform "soak" all over (Padded, Leather, Chain, or Plate) based on their armor type.  There are no partial suits of armor.
  • Heavy Plate gives only 6 points of Soak (as Standard Plate) but grants +1 Dodge.

Monday, August 17, 2015

Kinetic Energy of Strikes vs. Armor

I want to capture some data here about kinetic energy (Mass * Velocity ^ 2) of various strikes as well as armors.  This is important data about wounding and penetration capability.

STRIKES

ARMOR

* For different irons/steels, you can multiply these energies by: 
Munition quality iron: 0.5 
Low-carbon steel: 0.75 
Medium-carbon steel (Milanese): 1.1 
Hardened steel: 1.5 

DISCUSSION

So...  How is all this useful?

It informs a discussion of damage and armor systems.  We know that strikes inflict between 20J (average person with a knife) and ~350J (professional baseball player with two handed grip, world record boxer) of kinetic energy.  Typical break points include:
  • Light Knife, Underhand:  20-50J
  • Punches and Overhanded Strikes by strong people:  100-121J
  • One handed Weapons:  On order of 40-130J
  • Two Handed Weapons:  On order of 100-305J
  • Light Bows:  50J
  • Long Bows:  100J
  • Heavy Long Bows:  140J
Armors likewise protect against varying penetrating blows:
  • Padded:  20-50J (stacks with other armors)
  • Leather:  30J
  • Chain Mail:  80J
  • 1mm Plate:  55J (reasonable typical for lightly armored areas)
  • 2mm Plate:  175J (minimum for breastplates, helms)
  • Signficant Flesh Penetration:  ~30J
Slashing blows are about half as effective when defeating armor.

Those numbers are all rather large, so let's divide them by a common denominator, say, 25J, to get something more usable.

Modified numbers for strikes:
  • Light Knife, Underhand:  1-2
  • Punches and Overhanded Strikes by strong people:  4-5 (each standard deviation is +/- 1)
  • One handed Weapons:  ~2-5
  • Two Handed Weapons:  ~4-12
  • Light Bows:  2
  • Long Bows:  4
  • Heavy Long Bows:  6
Modified numbers for armors:
  • Padded:  1-2 (stacks with other armors)
  • Leather:  1
  • Chain Mail:  3
  • 1mm Plate:  2 (reasonable typical for lightly armored areas)*
  • 2mm Plate:  7 (minimum for breastplates, helms)*
  • 3mm Plate:  12 (not unreasonable for breastplates)*
  • Significant Flesh Penetration:  1+
*Cut plate defenses by 1/2 for cheap pot metal.  Increase by +50% for high-grade metal.

Interestingly, those numbers look a lot like usable numbers for damage rolls in a gaming context, do they not?  As a caveat, most of those damage numbers are high-end maximums (if only one number is given).  Most are also for penetrating force.  A slashing blow can do a more damage, but is less effective against armor by about half.

Strength Modifiers:  From the data on olympic boxers, we also have the data that each standard deviation adds or subtracts +1 (25J).  Now, olympic boxers are already above the bell curve, likely at least two standard deviations, but it is a reasonable modifier.

A SYSTEM

So now we start to get to a usable system.

Weapon Damage (average adult male):
  • Punch, Unarmed:  1d3
  • Light Weapon (Dagger):  1d6-1
  • One Handed Weapon:  1d6
  • Two Handed Weapons:  2d6
  • Light Bow:  1d6-1
  • Long Bow:  1d6
  • Heavy War Bow:  1d6+3 or 2d6-1 (or just 2d6 for simplicity's sake)
Strength bonuses:  Each standard deviation +/- 1 to above figures.
0-1 (-3), 3-5 (-2), 6-8 (-1), 9-12 (0), 13-15 (+1), 16-18 (+2), 19-21 (+3)

*As an optional rule, two handed weapons deal 1d6 (perhaps 1d6+1) damage as well but all strength modifiers are doubled.

Slashing weapons and strikes:  Roll one extra damage die and retain best against unarmored targets; roll one extra die and retain the worst against targets in chain or plate mail.

Bludgeoning weapons and strikes:  Bludgeons always do "bruising" damage, not lethal damage, but ignore the "soak" of armor.

Armor:

Armor mitigates incoming damage.  Characters select either to wear a helmet and either full or half armor.  Full armor protects the torso and extremities.  Half armor protects only the torso, like a breastplate or coat of mail.

Characters may layer lighter protection for extremities (such as greaves for legs and gauntlets for hands) as desired with half armor.  For example, you could choose a steel breastplate for the torso and leather gauntlets/leggings for the extremities.

Cloth padded armor may be layered with any other type for more protection.
  • Cloth:  Soak 1
  • Leather:  Soak 1
  • Light Plate:  Soak 2
  • Chain Mail:  Soak 3
  • Medium Plate:  Soak 7
  • Heavy Plate:  Soak 12
With this system there are several checks:
  • Attacker checks "to hit."  This is based on defender's agility.
  • If there is a hit, defender gets to "save" and see if their armor helped out.  Roll 1d6:
    • 1:  Head (Helm)
    • 2:  Arms (Gauntlets)
    • 3-5:  Torso (Armor)
    • 6:  Legs (Greaves/Chausses)
  • Attacker rolls damage.  Armor, if present in the targeted area, "soaks" incoming damage.
    • If the damage roll is less than the "soak," the defender takes a bruising hit.
    • If the damage roll is greater than the "soak," the defender takes a lethal wound.
    • Extra Damage:
      • Hits against the head and torso result in +1 Wound (i.e. two wounds).
      • If no armor is worn, a damage roll of >=5 also results in +1 Wound.
      • If armor is worn, a damage roll that exceeds the soak value of the armor by >=5 also results in +1 Wound.
  • Cover:  The "save" system above also factors cover into effect.  Decide what part of the body is protected by cover and negate hits to that area.  For example, a low stone wall covering half of a warrior's body would protect against any roll of 4-6.
Wounds & Damage:
  • Lethal vs. Bruising:
    • Most weapons deal lethal damage.  Bludgeons as well as unarmed strikes deal "bruising" damage; armor can also "soak" incoming damage, converting potentially lethal strikes into bruises.
    • Bruises recover rapidly.  Enough bruises stack up to lethal damage.
    • Lethal wounds recover slowly.
  •  Characters have the following hit points:
    • 6+/-CON Bruises
    • 4+/-CON Lethal Wounds
    • If a character can no longer take bruising hits, then all future "bruises" become lethal wounds.  This represents a badly battered character having ribs cracked, suffering concussion, and other serious and life-threatening wounds.
The wounds and damage system needs some work, but it could be ok.  As an alternative, you could simply use the damage and soak values as is, subtract the "soak" rating from the incoming damage, and use normal D&D hit points.