From: hall@bcstec.ca.boeing.com (Robert J. Hall)
Subject: net.rpg - A damage system
Organization: Boeing
Date: Tue, 15 Dec 1992 16:20:09 GMT

Here's bits and pieces of a sample damage system I'll throw out on the 
table for general critique and dissection (or just for laughs). All numbers,
of course, are bogus and just included for demo purposes.

--

Each strike by a physical weapon has the following two basic factors:

 - Kinetic Energy

 - Penetration area

The kinetic energy is determined by the velocity of the attacking
weapon and the mass of the blade. The actual kinetic energy will be
determined by the current attributes of the attacker; the effective-
ness of the attack; and whether any energy is lost prior to impact.

The penetration area is determined by the shape of the striking weapon
and the angle of the attack.

When the weapon strikes, the following effects occur:

 - Part of the energy is absorbed by armor and non-essential systems.

 - The remaining energy creates internal damage to essential systems.

--

Ignoring for the moment the effect of external armor, the following
sample damage outline shows three levels of damage detail.(From simple
to mind-boggling complexity.) The actual level of detail would be left
up to the GM.

  A. External
   1. Protection
     a. Hide
     b. Bone
     c. Fat
   2. Mobility
     a. Thigh Muscle
     b. Calf Muscle
     c. Knee
     d. Tendons
     e. Hip
     f. Feet
     g. Toes
   3. Weapons
     a. Muscle
     b. Tendons
     c. Hands
     d. Claws
     e. Jaws
   4. Sensors
     a. Eyes
     b. Ears
     c. Nose
   5. Miscellaneous
     a. Hair
     b. Groin
     c. Ear lobe
     d. Mole on right cheek
  B. Internal
   6. Power
     a. Heart
     b. Lungs
     c. Blood
   7. Energy
     a. Stomach
     b. Intestines
     c. Liver
     d. Kidneys
     e. Bladder
   8. Command
     a. Brain
     b. Spinal column
     c. Nerves
   9. Miscellaneous
     a. Vocal chords
     b. Tonsils
     c. Appendix

For the sake of sanity, Ill stick to the second level of complexity:

  A. External
    1. Protection
    2. Mobility
    3. Weapons
    4. Sensors
    5. Miscellaneous
  B. Internal
    6. Power
    7. Energy
    8. Command
    9. Miscellaneous

--

If a random target system is selected on the defender, then the damage
will either be inflicted against the exterior or the interior. If the
damage is against the interior, then part of the damage is absorbed by
the exterior.

Each weapon will have a weight and stop rating. When a weapon strikes,
the amount of damage is calculated using the weight; the appropriate
character attributes; and the effectiveness of the blow.

The target of the blow is then determined:

 - If the blow is external, then the damage is immediately applied
   to the selected target system.

 - If the blow is internal, the stop rating is added to the protection
   rating of the targeted area. The result is the external damage.
   The external damage is then subtracted from the total damage, and
   the remainder is applied to the internal system target.

Each internal target will list an external damage factor. This is applied
first to Armor, unless otherwise stated in the damage chart.

Here's a sample of a Level 2 systems table for a human character:

    %    Target  External System  Serious  Critical  Level  Armor
  -----  ------  ---------------  -------  --------  -----  -----
  01-30    -1    Protection         10        20
  31-40    -3    Mobility            6        12
  41-50    -3    Weapons             5         8
  51-55    -6    Senses              1         2
  56-60    -5    Miscellaneous       3        10

    %    Target  Internal System  Serious  Critical  Prot.  Armor
  -----  ------  ---------------  -------  --------  -----  -----
  60-65    -4    Power               1         2       4
  66-85    -2    Energy              2         4       2
  86-90    -3    Command             1         2       3
  91-00    -2    Miscellaneous       2         5       2

When a random target is required, percentile dice (or whatever) are
rolled and the appropriate system target selected. (The Target column
is the penalty for an attack against that specific target.)

The point damage against the appropriate system is determined (somehow).
If the damage is above the serious level, the character is seriously
wounded and suffers a level loss of system effectiveness. (Hits below
that level are minor wounds.) When the damage reaches Critical, special
damage effects are incurred. (Character is unconscious; a limb is maimed;
and so on.) For Internal system strikes, the Protection rating is applied
to the external damage before internal damage is calculated.

The effects of a loss of system effectiveness could be as follows:

  Protection  Reduced ability to absorb internal damage
  Mobility    Loss of speed and agility
  Weapons     Decrease in combat weapon/shield skills
  Senses      Temporary loss of sight, hearing, etc.
  Power       Reduction in actions per round
  Energy      Unable to recover strength
  Command     Stunned, dizzy, paralysis, and/or unconsciousness
  Misc.       Special effects.

Level is the number of step levels of system effectiveness. Armor
is the damage absorbed by artificial armor. (Chain mail, leather, etc.)

Bits and pieces of armor could be rated, for example, by the protection
they provide different systems. A Helm, for example, could provide 20
points to Command; 15 points to senses; 5 points to external misc.; and
5 points to armor. The armor points for each system are then totalled
and entered into the appropriate Armor slot. The result is subtracted
from damage.

Armor designed to absorb a blow would have high external armor ratings.
Those designed to prevent penetration would have better internal armor.

--

Heres part of a sample weapons table:

  Weapon      Weight     Stop    ...
  ---------  --------  --------  ...
  Mace          5          8     ...
  Scimitar      4          4     ...
  Spear         4          2     ...
  ...

Suppose the Mace inflicted 14 points to the Internal Power system of an
unarmored target. The first 8 points of damage are applied to External
due to the stop factor. An additional 4 points of damage are applied to
Protection. Finally, the remaining 2 points are inflicted on the Power 
supply. This is enough to inflict a Critical result. (Could be a pierced 
heart, punctured lung, or bleeding artery, for example.)

--

For an even easier simpler damage system, the results can be reduced to
External or Internal damage. The factors for each would be a weighted
average of the more detailed 2nd level damage system. Each creature
description would have, as a bare minimum, stats for External/Internal
damage. More effort can then (optionally) be extended to develop a 2nd
or even a 3rd level damage table. (The later would probably be a
requirement for any player-character races.)

-- 
 Bob Hall                   |  if [ -bs message ]; then
 Boeing Computer Services   |      mv message /compost/heap/$$
 root@chicken.ca.boeing.com |  fi
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