GURPS Melee Damage pt. 3.5

Well, here’s how I got to what I posted last week (part 3) and some stuff about how I failed to come up with a proper formula and stuff… But first science, that’s always fun. Though this one might not be that interesting, as it’s just some background and stuff. Whee.

Physics! Yay

So, googling around the interwebz seems to reveal almost no easily available speeds on how fast weapons can be swung. I did, however, find some data on baseball bat swings, which I will use as a substitute. It’s not a perfect fit but better than nothing. The top-end swing speed seems to be around 45 m/s for the best recorded results. This is definitely an all-out-attack (strong), which means that the “normal” swing is a bit weaker here. I think +1 damage per die could be averaged out to around +25% damage overall. This means the fastest non-berserk swing should be at around 35 m/s. Compare that with the 20 m/s for the world’s fastest punch. I assume that that’s also an all-out-attack, meaning a two-handed swing is 125% more powerful than a one-handed thrust. How much of that is two hands and how much is the swing? Hard to say. Maybe it’s more about being able to swing a higher weight in your normal speed.

I assume for now that you cannot swing two hands any faster than you can swing one. It allows you to swing heavier things in your normal speed, but apart from that you might be actually be able to add speed to a weapon by rotating the “hilt” a bit. 5 m/s? It’s just a wild guess, if anyone knows better please do tell.

Energy of Attacks

GURPS has a formula for bullet damage based on the shot’s kinetic energy and cross section. As the base damage of an attack is more accurately called penetration, this very much makes sense. That’s why speed is important, as kinetic energy  [J] is equal to mass [kg] times velocity  [m/s] squared, divided by two. So that’s the basis, and you apply that in a formula I think I linked here. I’m going to use this for the damage for melee weapons, despite them technically not being bullets. Not using two different formulas for damage should be good, right?

Strength to Damage

For this one I’m going to assume that the world records are made by people with 20 Strength for striking purposes. I feel this is a reasonable level, as for comparison 20 Strength in lifting allows you to carry 360 kg (800 lbs) without expending fatigue if I’m not confused. Sounds pretty high, compared to world records of ~450 kg which definitely makes people tired. But 20 should probably be some kind of limit for regular human strength, hard or soft. And for now, I’m focusing purely on the human scale of things.

Baseball Bats

According to Wikipedia, the weigh about a kilo, and is about a meter long.

So How Did I Do It?

I used the ballistic formula, inputted the maximum speed (45 or 20 m/s) as well as the weapon weight (plus either the full 2 kg arm weight for a thrust or half that for a swing). I used that as the 20 strength A-o-A. And that’s like it… Yeah… I’m not sure how much damage loss a cutting blade would be (worse transfer of energy), so that should factor in too, but to what degree..? I’ll have to think on this for a while longer…

I tried to come up with a general formula that’s easy to use, but I didn’t have time to finish that last week and now I’m distracted with other projects.So yeah, this is possibly not the end of this series. Unsure if it’s going to end up playable but I feel like a new kind of scaling fits better, as now the damage difference between different weapons doesn’t gets smaller when your strength goes up instead of staying similar. But this is it for this time, another part (if any) requires more thought.



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