ST damage formula

[zoncxs]

so I finally made a neat formula that you can use to determine how much damage a given ST can do for both swing and thrust.

the formula assumes using the (N+1)d-1/+0/+1/+2 formula that ST10-22 is based on (1d, 1d+1, 1d+2, 2d-1, 2d etc)

for swing: ((ST-10)+4)/4 = dice of damage.

for thrust: ((ST-10)+4)/8 = dice of damage.

decimals are treated as such:

less than or equal to .25 = add 1
less than or equal to .5 but more than .25 = add 2
less than or equal to .75 but more than .5 = add 1d-1

so, lets say you want to know ST 14?

14-10 = 4+4 = 8/4 = 2d6 for swing
14-10 = 4+4 = 8/8 = 1d6 for thrust

what about, say, ST50?

50-10 = 40+4 = 44/4 = 11d6 for swing
50-10 = 40+4= 44/8 = 5.5 = 5d+2 for thrust.

ST 2550? 636d6 for swing and 318d6 for thrust

so what do you all think? :D

[vierasmarius]

Originally Posted by zoncxs

so what do you all think? :D

I think it's a decent alternative to using the formula in Pyramid 3/34 (which gives ST/2-10d or -8d for high ST thrust and swing). It does break with the convention of both the Basic Set damage table and the Pyramid one which makes swing and thrust damage vary by no more than ~2d, but I suspect that's the issue you were trying to address anyways.

[DouglasCole]

Originally Posted by vierasmarius

I think it's a decent alternative to using the formula in Pyramid 3/34 (which gives ST/2-10d or -8d for high ST thrust and swing). It does break with the convention of both the Basic Set damage table and the Pyramid one which makes swing and thrust damage vary by no more than ~2d, but I suspect that's the issue you were trying to address anyways.

Yeah, there are quite a few potential solutions to this one. Letting them continue to deviate works. The cleanest is to probably decide how much extra oomph swinging gives over thrusting as a force multiplier, take the square root of that, and then multiply your ST by that number and plug it into the thrust formula.

If you want to git wacky, you can re-scale thrust to 1d per 10 ST, and that brings it much more in line with other damage quantities in GURPS.

[vierasmarius]

Originally Posted by DouglasCole

If you want to git wacky, you can re-scale thrust to 1d per 10 ST, and that brings it much more in line with other damage quantities in GURPS.

While that's certainly a "clean" progression, that ends up costing 50cp per 1d of thrust damage (using Striking ST), so I'm not sure how that is in-line with other damage quantities. Would you care to elaborate on that?

[DouglasCole]

Originally Posted by vierasmarius

While that's certainly a "clean" progression, that ends up costing 50cp per 1d of thrust damage (using Striking ST), so I'm not sure how that is in-line with other damage quantities. Would you care to elaborate on that?

1d per 10 ST would require repricing ST, I think I have an article stub (search search search here) where I go into why.

Short version is that ST-based damage scales too fast, and hits a value where you can punch as hard as many pistols shoot very quickly. That's a bit of thread necromancy, but basically, there's a case to be made that GURPS "damage" is really "penetration of stuff," and that means it would be more consistent all over the damage scale if quadrupling your energy input doubled your penetration.

If you keep a person the same size, and double his ST, you quadruple his input force (and applied over the same distance, you can handwave that as Force x Distance = Energy) and say his input energy quadrupled. So if you do damage based on (say) ST/10, then ST 10 = 1d, ST 20 = 2d, ST 40 = 4d . . . that is, every time you quadruple energy (double ST), you also double damage.

That's the same basic scale as in The Deadly Spring and that has been for firearms scaling since High Tech (2ed?) had DR 70 = 20d = 1" of RHA Steel.

[vierasmarius]

Originally Posted by DouglasCole

1d per 10 ST would require repricing ST, I think I have an article stub (search search search here) where I go into why.

Short version is that ST-based damage scales too fast, and hits a value where you can punch as hard as many pistols shoot very quickly. That's a bit of thread necromancy, but basically, there's a case to be made that GURPS "damage" is really "penetration of stuff," and that means it would be more consistent all over the damage scale if quadrupling your energy input doubled your penetration.

Interesting... I see that in your short damage article, you gave ST half the damage output of your earlier post in this thread. I suppose that, while realistic, it's a far more drastic change than just setting thrust damage = ST/10. Hmm... maybe unarmed attacks should be given a (0.5) armor divisor, similar to how cutting weapons (per Low Tech) only penetrate armor if they exceed double it's DR? That would keep unarmed penetration low, without nerfing damage too much... It also seems easier than going the route of doubling all armor DR and giving firearms AD (2).

If you keep a person the same size, and double his ST, you quadruple his input force (and applied over the same distance, you can handwave that as Force x Distance = Energy) and say his input energy quadrupled. So if you do damage based on (say) ST/10, then ST 10 = 1d, ST 20 = 2d, ST 40 = 4d . . . that is, every time you quadruple energy (double ST), you also double damage.

That's the same basic scale as in The Deadly Spring and that has been for firearms scaling since High Tech (2ed?) had DR 70 = 20d = 1" of RHA Steel.

This makes perfect sense. Going further, would it be possible to calculate how much force a particular ST could generate with a punch or kick, and use that to determine a more exact GURPS damage rating? I suppose there are a lot more factors to human limbs than bows, so it may not be feasible. Skill likely has a lot to do with it too, as training lets fighters put more of their mass behind their strike.

[DouglasCole]

Originally Posted by vierasmarius

Interesting... I see that in your short damage article, you gave ST half the damage output of your earlier post in this thread.

Yeah, ST/10 was for swing; I forgot that.

I suppose that, while realistic, it's a far more drastic change than just setting thrust damage = ST/10. Hmm... maybe unarmed attacks should be given a (0.5) armor divisor, similar to how cutting weapons (per Low Tech) only penetrate armor if they exceed double it's DR? That would keep unarmed penetration low, without nerfing damage too much... It also seems easier than going the route of doubling all armor DR and giving firearms AD (2).

Honestly, I might do both, limiting damage and using the (0.5) or even (0.1) armor divisor . . . fists just don't punch through solids well.

Remind me of this post in about three weeks. There's a concept in an upcoming Pyramid article that's relevant here. :-)

[ErhnamDJ]

Originally Posted by vierasmarius

Skill likely has a lot to do with it too, as training lets fighters put more of their mass behind their strike.

Maybe limit damage based on skill? Damage can't exceed skill/4 with a punch and skill/3 with a kick? It would at least be easy to keep track of and write down on a sheet. Also gives a reason to AoA and go Telegraphic.

[vierasmarius]

Originally Posted by DouglasCole

Yeah, ST/10 was for swing; I forgot that.

I could see using ST/20 Thrust for realistic games, but ST/10 for more cinematic ones (much as you included both Realistic and Cinematic damage outputs in your Deadly Spring article).

Honestly, I might do both, limiting damage and using the (0.5) or even (0.1) armor divisor . . . fists just don't punch through solids well.

Might this be related to unarmed fighters injuring themselves when striking rigid armor? Even without a fractional armor divisor, an attacker is as likely to damage his hand as his target. Realistically they may tend to instinctively pull their punches, or use a weaker strike (Hammer Fist or even Shove) that's less likely to hurt their hand.

Remind me of this post in about three weeks. There's a concept in an upcoming Pyramid article that's relevant here. :-)

I look forward to it!

And now, I'm off for pizza. (Hmm, how much DR does a crust have? And do human teeth have a fractional AD? Does it matter if it's incisors or molars?)

[Refplace]

Originally Posted by DouglasCole

Remind me of this post in about three weeks. There's a concept in an upcoming Pyramid article that's relevant here. :-)

I was thinking an article on alternate ST and scaling might be good for the Alternate GURPS issue of Pyramid