GURPS Project Strength (Fixing ST and ST-based damage and more!)

[ErhnamDJ]

I've been working on this for a while. What I've been doing is trying to convert Basic Lift to wattage (which I think I have worked out) and using that to figure out acceleration (which I don't know how to do, though I have ample baseball literature which seems to have the math in it), and then applying that to the mass of the weapons (which I believe I've figured out how to get for swung weapons) to get the final delivered kinetic energy.

If y'all are already messing around with Basic Lift, it seems like that way might be easy enough to do with a spreadsheet for someone who knows how to do the math, and would yield realistic results.

All I need to do is find out how to go from Joules out to the speed of the weapon. The results won't be pretty, but we can make tables for each weapon from them, which would be easily computerized for those who play electronically. And I don't really think it would be that difficult to look up on a table.

[Polydamas]

Originally Posted by ErhnamDJ

I've been working on this for a while. What I've been doing is trying to convert Basic Lift to wattage (which I think I have worked out) and using that to figure out acceleration (which I don't know how to do, though I have ample baseball literature which seems to have the math in it), and then applying that to the mass of the weapons (which I believe I've figured out how to get for swung weapons) to get the final delivered kinetic energy.

I personally think that any approach using high-school physics is likely to be more misleading than helpful. The physics of hand-to-hand combat is at once simple (Aristotle works!) and very hard to quantify. Someone who knew both physics and fighting might be able to do something useful, although in practice I think that the real answer would be "run a lot of experiments, get the values empirically, then extrapolate."

[Polydamas]

If swing damage is at least twice thrust damage, then swinging is almost always the best mode of attack (swing wounding with a cut is at least equal to wounding for an impaling thrust to the vitals, and basic damage is higher for penetrating armour). A better rule would be to let swinging do 50% more damage, or leave it up to the weapon (maybe swinging an axe is +3 damage per die, while swinging a sword +2, and swinging a knife +1).

Reworking the whole damage-penetration-wounding system without adding complexity would be a lot of work. For armour penetration, I toy with the following:

Compare average damage to DR. If average damage < DR, the attack fails (note that there is always a chance of a critical hit which reduces DR). If DR <= average damage < 1.5 * DR, the attack penetrates for half damage before wounding modifier. If average damage >= 1.5 * DR, the attack penetrates for full damage.

This requires one more stat for each weapon, but one could combine that with the armour divisor.

[Landwalker]

It's probably never a good idea for me to try to think about things very hard before lunch, but I've been mulling over what to do about blunt trauma and weapon damage types some this morning, and here are some ign'ant thinkings on the matter:

1. Crushing
   • Flexible Armor
     • Treat crushing damage as having AD(2) against flexible armor. So a DR 10 (2d+3) hauberk of Fine Mail becomes, for purposes of protecting against a mace, DR 5 (1d+2). Against a mace-wielder with ST12 (the minimum required for the weapon), that's a pre-armor damage of 4d+1, and you're looking at 3d-1 injury post-armor. Average of 9.5 injury (bearing in mind that the mirror-man he's fighting does have 30 HP, but that's still a good chunk of hurt). On an All-Out Attack, we're looking at 4d (average 14 injury and a very good chance of a major wound).
   • Semi-Rigid Armor
     • This is stuff like Scale, Jack of Plates, and Mail-and-Plates. Treat crushing damage as having AD(1.5) against such things (round up). This gives DR 10 (2d+3) Medium Scale an effective DR 7 (2d+0). Now our mace-wielding maniac is looking at post-armor damage of 2d+1 (average 8 injury) on a regular attack, and 4d-2 (average 12 injury) on an All-Out Attack.
   • Rigid Armor
     • Nothing fancy here. Full DR, and full damage afterwards. Against Medium Segmented Plate (DR 10/2d+3), a regular attack yields 2d-2 (average 5 injury), and an All-out Attack yields 3d-1 (average 9.5 injury).
   
   
2. Cutting
   • Flexible Armor
     • The calculation here is identical to that for Crushing Weapons/Rigid Armor. All damage is converted to crushing. However, if the post-armor damage exceeds the Armor DR in absolute terms (e.g. more than 10 damage rolled against Fine Mail), the blow penetrates the armor and becomes cutting. With a broadsword, this happens about 50% of the time at ST20 on a regular attack, or at ST15 on an All-Out Attack. With a greatsword, those 50% levels are ST16 and ST13, respectively.
   • Semi-Rigid Armor
     • As above, but with an Armor Divisor of (0.75). To cut through the armor, the rolled damage must beat DR/0.75 (which is 13 for Medium Scale). Even a greatsword is going to have a tough time with that—it gets penetration about 50% of the time on ST16 for an All-Out Attack.
   • Rigid Armor
     • As Semi-Rigid Armor, but with an Armor Divisor of (0.67). Good luck cutting through that plate! To have a 50% chance at cutting through Medium Segmented Plate, you're going to need a Greatsword, ST19, and an All-Out Attack. Remember folks, don't hit the armored bits.
       I considered using an armor divisor of (0.5) for Rigid Armor, which would give Medium Segmented Plate an effective DR of 20 instead of 15. At DR 20, you're pretty much never, ever going to cut through it, and unless you have at least ST15, you're never going to do any damage at all on a regular Attack. That seemed a wee bit much for me.

Have to run out now, unfortunately. Still trying to figure out what to do with Impaling damage. I definitely want to allow the possibility of crushing injury from a spear thrust, but the penetrating potential also definitely needs to be higher than it is for cutting. I've got an idea or two, but won't have time to write them up and examine them until this evening. Figured I'd throw out what I've got so far before I head out so that better minds can skewer it in my absence.

Edit: Back, and here's some Impaling thoughts:

1. Impaling
   • For all armor types, apply an armor divisor of (1.5). If your rolled damage exceeds 50% of the armor's modified absolute DR, then the blow penetrates the armor and is treated as impaling damage. Damage rolls equal to or less than this figure are treated as crushing damage.
     
     
   • Example: Fine Mail is DR 10 (2d+3). With a (1.5) divisor, it becomes DR 7 (2d). Penetrating it will require a damage roll of at least 4 (a 50% chance for a two-handed spear at ST 14, or at ST 11 on an all-out attack).
     
     
   • Note that, if you're relying on your armor, be afraid of the guy with the pick. He'll have a 50% chance of penetrating your Fine Mail on a regular attack at only ST11. On an All-out Attack at ST11, his odds are something like 92%. The "good" news is that his pick is probably stuck in you, so whack him while you have the chance!

So, there we have it for my first pass at what to do about damage types and blunt trauma. You may now mock my ideas.

[ErhnamDJ]

Originally Posted by Polydamas

I personally think that any approach using high-school physics is likely to be more misleading than helpful.

I don't know what that means. Are you saying we shouldn't be trying to figure out the delivered kinetic energy to determine damage?

I think that the real answer would be "run a lot of experiments, get the values empirically, then extrapolate."

I think the numbers in these biomechanics books, papers on baseball physics, and the numbers I got from watching a large number of YouTube videos of people fighting are derived empirically.

[TheVaultDweller]

:sigh:
It's 2:30 AM here and I have stuff to do tomorrow, but I can't resist.

I feel there's a bunch of us seeing the same things and coming to very similar results with a few twists here and there. I actually feel a bit frustrated because I've spent a good portion of the last few days hammering a VERY comprehensive overhaul of ST-based damage just to come here and see that either I did some unecessary work because the information was buried in here somewhere, or someone else did the unecessary work because I did it first but hadn't posted yet. Anyway, someone ended up doing double work.

I feel we could use some structure in combing the best pieces of each other's work and submitting it to critique. When I was doing MY changes I kept coming up with fringe cases where things broke down and had to think on a solution. I belive this process could best be done in some collaborative way. Anyone interesting in doing this?

Anyway, I have a LOT of thought behind my system that I can't post right now, but this is gist of what I've come up with. I've ran a few combat scenarios and it seems solid. So, here it goes:

• Assume Last Gasp and Technical Grappling rules are in effect.
  
  
• Make normal humans have HP equal to STx2
  
  
• Fix ST-based damage at 1d Thrust and 2d Swing for ST-10. Swing gains +1 per point of ST and thrust gains +1 for every other point of ST (with ST 11-12 being 1d+1 already). This is actually the realistic scale from DouglasCole work rebalanced for 20HP humans.
  
  
• Double DR of all armors and other DR-giving traits.
  
  
• Firearm damage remains the same, but adds a (2) Armor Divisor.
  
  
• Use the Trained ST table for ALL combat skills. Swords and knives would be on the fast progression, most other melee weapons would be on the average progression and unwieldy things like Whips and Flails on the slow. For unarmed, Boxing and Karate on the fast progression, Brawling on the average.
  
  
• Humans have DR 2 (Crushing only) on the chest/abdomen and DR 1 (crush only) on the limbs. DR 4 on the skull (this is the RAW DR 2 just doubled for the new HP scale). Hands, feet, neck and face have no DR.
  
  
• Unarmed attacks by fists/kicks have an Armor Divisor of (0.5). Anything that gives a tougher surfaces gets rid of this modifier (i.e, boots for kicks, any fist-load on the hand, etc).
  
  
• Divide Cut attacks into Cut-, Cut, Cut+ and Cut++, just like with piercing attacks. Same damage multipliers as the piercing ones. Good kutting swords (sabers, katanas, falchions, longswords, etc) have Cut++. Most other bladed weapons have Cut+ (which is the same as the 1.5 wound modifier we have now) and some marginally cutting weapons (like edged rapiers or knives) have Cut. Almost-blunt things technically capable of cutting, like smallswords, claws of small animals and stabbing knives will have Cut-.
  
  
• Make impaling weapons all be Piercing. The size of the piercing modifier will depend on lenght and width of the penetrating point. Small, hard points have a (2) armor divisor but tend to be pi or pi-. Most swords are Pi++ or Pi+, except fencing weapons (who tend to be pi). A halberd will be a Swing, pi++, hardened (2) Armor Divisor attack. Scary.
  
  
• Use the edge rules from low-tech against cutting attack. That is, if a cut attack of any kind is less then two times the target DR, it counts as a blunt (crushing) attack.
  
  
• Make blunt trauma from flexible armor be 1 for every five points of damage the armor stopped. Count the DR 2 of the human torso against crushing attacks as flexible for this purpose and "layer" it with whatever armor is used on top of it.
  
  
• Body Hits to the torso (from High Tech) applies like this: piercing attacks to the torso can't cause more then 1xHP of damage per attack, but attacks to the vitals have no such limit.
  
  
• Any piercing attack to the chest has a 1-in-3 chance of hitting the vitals. You can also target the vitals normally, of course. This makes the Vitals easier to hit.
  
  
• No C-range attack can use Swing damage. A knife at close quarters can cause both cut and piercing wounds, but all based on Thrust damage. Swing damage represents attacks with some mechanical leverage. Also, generally reduce the Swing damage bonus that weapons have to either zero or negative numbers. Only unbalanced weapons should have substantial swing damage bonuses.

If you do this, you will find these results:

For unarmed combat: Two equally barely trained (Brawling-10), ST10, opponents will be largely innefective at actually injuring each other. They will probably be throwing a lot of Telegraphic AoA (Strong) unaimed attacks at each other. Combat will be decided by whomevers get tired first (suffers crippling FP loss from Last Gasp) and gives up, or whomever first lands a critical hit or a luck blow to the face that forces the other guy to make a knockdown test. Better trained fighters will be more likely to be able to get those face shots to end the fight, and they can be dangerous with brass knuckles or any kind of fist load. If you want to hurt someone bare handed, grapple them, get a joint lock and start twisting or do a throw from lock. This is realistic, IMO.

Armed combat without armor: This is scary as hell. Swords in particular will be deadly. Figthing defensively and hoping for luck are your best bets. Injuries will be quite brutal. Fencers who keep their distance will be VERY dangerous.

Armed and armored combat: Cuts become largely useless. Damage happens mainly by high-damage crushing attacks (which don't cause a lot of wounding at any one time, but can batter the enemy down even in armor), specialized thrusting weapons with (2) armor divisors and targetting chinks in armor (combine with the specialized thrusting weapons, for even greater effect). Warhammers and poleaxes will be VERY scary. Grappling the guy in plate armor and getting a dagger in his armpit is very good as well. Again, realistic.

Firearms: Shooting a guy in the torso with a 9mm (2d+2 pi) will result in an average of 9 damage, which is significant but not a "manstopping" injury. For that, you need a Vitals hit. With a vitals hit the same shot now causes 27 points of injury, which is a Major Wound and drops a normal 20HP man to minus HP territory and that means he's going to fall unconcious right away or in the next few seconds (HT rolls every second). That means that shot placement is necessary to reliably stop people with handguns and, at the same time, it's quite possible to survive being shot a couple of times in the chest, as long as you're lucky enough for not getting hit on the Vitals and the attacker rolling Medium-to-Low results for the damage (this is also realistic). For rifles and shotgun, for the most part, if you hit them, they will drop. Rifle shots to the vitals will most likely result in actual instant death.

[DouglasCole]

Originally Posted by TheVaultDweller

I feel we could use some structure in combing the best pieces of each other's work and submitting it to critique. When I was doing MY changes I kept coming up with fringe cases where things broke down and had to think on a solution. I belive this process could best be done in some collaborative way.

More thorough response when I have more time, but this seems a very good gameable start, and with a few exceptions, which I'll call out later, and one or two tweaks would work well.

[TheVaultDweller]

Originally Posted by DouglasCole

More thorough response when I have more time, but this seems a very good gameable start, and with a few exceptions, which I'll call out later, and one or two tweaks would work well.

Great, I look forward to it.

Now that it's not the wee hours of the morning, I can explain a bit what were my thought processes to get to these. I followed these three principles:

1) No multiplications, table lookups or log scale stuff. Math has to be kept at the same basic level of RAW. That is, you only do sums and convert dice.

2) Don't add any more dice rolls then RAW has to resolve an attack. That means one attack roll, one defense roll and one damage roll.

3) Try to avoid as much as possible creating new mechanics when what's in RAW can be re-purposed to fit. That means, for example, not using the rule you proposed here. Rolling HT for avoid injury is not on RAW, so that means is a completely new mechanic and, thus, I will try to get round the "boxing match" problem some other way.

The purpose of sticking with the above three rules is to make things easy to use and be able to be "dropped in" without having to mess with a ton of other stuff. The idea, for me, is that this system becomes the new "RAW" for my campaign and it's easy for me to iterate on it, as well as adapt regular content of the GURPS line to it without having to do a lot of work.

So, I only changed numeric values (2xHP, the new ST table, firearms armor divisors, etc), or made very minor rules alteration. The most significant one is the adoption of the -, base, + and ++ symbology from piercing attacks to cuts. I guess saying that humans have some inate DR counts as well, but it's a very easy to remember minor effect and it's crush-only, so it doesn't disturb the system too much, IMO.


As for the damage types, I feel that a simplification/streamlining was in order, while at the same time making them more nuanced. I divided damage types as follow:

1) Crushing damage is caused by blunt force trauma, high-speed collisions, falls, etc. It covers all forms of non-penetrative trauma to the body. You can divide it into crushing attacks proper, represeting things like being hit with something hard like batons, maces, a car, the ground, etc. That's a regular cr attack, with no armor divisor or wound multiplier. Then there are atttacks made with relatively soft or padded material, the main one being unarmed attacks. That's a crushing attack with a (0.5) Armor Divisor. I didn't renamed it on the post above, but I figure it could be understood as a cr- attack to keep the notation consistent. Anything softer then this counts as a knockback-only attack (fire hose, shoves, being hit with a giant exercise ball, etc). These attacks are innefective at both penetrating armor and causing injury, so they are the least useful form of damage you can deal, but it does have some hidden advantages. First, it is very effective against flexible armor. Second, it has no ovepenetrating risk, if you're hit with enough force, you'll be squashed into a paste and you'll be dead, period. Lastly, it's the easiest attack to make use of leverage. A mace will have a high swing damage and a mace can be something as simple as a stick with a rock tied to one end. To sum up, a strong person can do significant damage with it, even if it's not as efficient as the other two damage types, and it's easy and cheap to make a weapon that can take advantage of that strength.

2) Cutting attacks represent tissue-penetrating damage caused by a large striking surface (i.e, a blade). They can cause gross physical trauma, meaning that according to RAW they don't over-penetrate. Some sort of high-powered robot can hit someone with enough damage to cause instant death (-5 x HP), meaning you cut the person in half. They are also highly effective against limbs and extremities (where pi+ and pi++ attacks have no wound multiplier). You can have a balanced weapon, like a sword, cause this kind of injury with the much better swing damage values. This is a extremely important consideration, since a balanced weapon is much more effective at defending. Disadvantages of this is that it is very weak against all forms of armor and that while it's easy to give crippling injuries to the limbs, it's much harder to make quickly fatal hits to the torso (you can't target the vitals) and since it's generally tied to high swing damage, it's more useful to strong persons, though strength is far less important than on crushing attacks (due to the wound modifier).

3) Piercing attacks representing tissue-penetrating damage caused by a narrow, small surface or projectile. This is relatively weak against limbs and it can waste a lot of it's power overpenetrating the target if it doesn't hit anything important (a torso hit without Vitals). On the plus side, it can target more precise locations (eyes, chinks in armor, and, cruacially, the Vitals). A piercing attack can also be made to penetrate armor better, by using a hard material specially shaped to defeat the armor, thus giving a (2) or better armor divisor. It's also generally much easier to manufacture a decent piercing implement then a effective cutting one. This makes it the most basic form of improvement over raw blunt trauma and, incidentally, the first purpose-built weapons mankind devised after the club (i.e arrows and spears). It tends to favor skill more then strenght and it can be made into a very quick weapon, capable of recovering very rapidly from parries/beats. This comes to the pinacle with the rapier, a weapon unmatched to this day for unarmored dueling. It's reach and parrying ability keep you safe, while it can deliver deadly attacks to the Vitals, Neck and Face, all targets where it's pi type wound would not be a drawback, due to generous wound modifiers for these regions already. It can ALSO be made into an effective anti-armor weapon.

So, by tweaking with these things, armor divisors, wound modifiers, etc, I think it's possible to come up with a fairly good representation of the relative deadliness of unarmed, armed and firearm damage, as well as things like the evolution of armor and sword design, while changing as little as possible of RAW. Anyway, that's what I'm going for.

I hope this stuff is useful to others. Cheers!

[TheVaultDweller]

I also remembered to say something about Swing damage.

As I envision it, Swing damage is the kind of damage you do when you can leverage core muscle groups and use your extended limbs as a leverage device. So, you neeed to, well, swing to be able to claim it :)

That has some ramifications, the most important of which is this: It means no attack at close quarters can be a Swing attack, because you lack the leverage for it. Closing with your foe becomes an effective tactive for a unarmed person trying to survive against an armed one. This is, again, realistic. Every martial arts that teachs unarmed against armed is all about closing in and negating your foe's advantage by reducing the engagement distance (as well as grappling, most of the time).

This also has some bearing on spacing. Historically, one of the reasons stabbing weapons have been prefered in both war and civilian use is because a stabbing weapon allows a tight formation, whereas troops equipped with axes and things like that require more maneuver room to swing the weapons properly. In civilian context, rapiers and knives were preferred, among other reasons, because narrow urban streets would cause difficulties for a slashing sword. This also makes knives, specially stabbing knives, very, very dangerous at close quarters. Which they are in real life, so, that's a bonus.

I'll even scale this to SM. Meaning that a SM 0 human needs a Reach-1 attack to be able to claim a Swing modifier and a SM+2 giant needs a Reach-3 attack to do it. If the heroes can get inside this rather large radius, they can work "inside" his weapon. For a giant, that sword of yours is like a dagger!

This works beutifully with a rule I found in a article in Pyramid 3-34, called Distance and Defence. This rule basically states that if you need to close distance to strike at your opponent, he defends at +2, that if your attack starts at striking distance (other then C) it is solved normally and that if you start a attack from ALREADY being at Reach-C, the defender is at -2. Again, this works very, very well to represent the deadliness of daggers and the importance of proper spacing. Oponents with longer reach will want to keep foes at bay and people with shorter weapons face the prospect of trying to close in, which is diffcult and potentially dangerous (due to stop-thrusts), but can grant big rewards.


There's one snag to all this, though, and that's the fact that all the weapons in Low-Tech and Martial Arts need to be statted again :(

All C-attacks need to be based on Thrust, you need to assign proper pi-, pi, pi+ or pi++ modifiers to all formely impaling weapons and do the same thing for cuts. I would also adopt the following rule for swing damage: Very light one-armed weapons cause Swing-4 damage and gigantic unwieldy reach-2+ maul cause Swing+6 damage, and adjust everything in between based on these two extremes. Most swords will be in the Swing-2 to Swing+1 range, with some fringe cases like very light fencing swords being worse and large greatswords being better.


So far, I have failed to see a way around this need. Between the new HP scale, the new wound modifiers and other things, re-stating melee weapons is pretty much a requirement. This is probably for the better, though, because a browsing of Martial Arts I did a while ago turned up some very dubious values for some weapons, IMO. I guess Low-Tech is probably a bit better at this, but I haven't reviewed their stats. Anyway, there's probably far too many weapons in Martial Arts, anyway. We can narrow it down substantially and treat most of the "types" of weapons as something that's either Cheap/Fine/Balaced whatever and trough familiarity modifiers.

[Anthony]

Originally Posted by ErhnamDJ

I've been working on this for a while. What I've been doing is trying to convert Basic Lift to wattage (which I think I have worked out) and using that to figure out acceleration (which I don't know how to do, though I have ample baseball literature which seems to have the math in it), and then applying that to the mass of the weapons (which I believe I've figured out how to get for swung weapons) to get the final delivered kinetic energy.

This really isn't going to work very well due to the complexities of how muscle tissue actually works, though this might be useful. Also, based on the problems you're having I think you may need more physics than you have to do even a basic job.