Statting Custom Weapons

Games Discussion Ars Magica
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Any advice for how one would go about figuring out what stats a weapon ought to have if it isn't one the rules already cover? As a thought experiment I decided to try building some characters from the Berserk manga, and while most of them are pretty easy since they use standard armaments and I can use the effect-building systems for the supernatural stuff, Guts is an outlier.

First of all is sizing up a pre-existing weapon - he uses a great sword called the Dragonslayer which nobody but him is strong enough to use effectively because it weighs 400 pounds, since (per its namesake) it's designed to have enough swinging force to cut through the natural armor of dragons, demons, and other supernaturally resilient enemies. So I'd increase the Minimum Strength column probably all the way up to +6, as I'd probably build Guts with Giant-Blooded and Great Strength x2 to cap him out, but what should that do for the rest of its stats? I'm not sure whether the greater reach of the weapon would increase its Initiative or if the huge inertia would lower it or whether those effects would cancel out. Same with the Attack & Defense modifiers, really - the blade is so wide that Guts effectively uses it like a shield on occasion (using the flat side to deflect arrows and such) and it gives him a reach advantage so maybe it's a plus, but then again it's harder to use with the dexterity of a normal blade. The only sure thing is Damage going up, but even then it's hard to decide exactly how much is appropriate. This is probably the most YMMV element, but if anybody has ideas for a ratio of how increasing the size and weight of a weapon would affect its stats, I'd be interested in hearing them.

The second one is a whole thing in its own right. Some of Guts' arsenal are things the rules cover, throwing knives and a crossbow built into his prosthetic arm, but the big one is the literal hand cannon (not like "predecessor to modern guns" but like "his hand detaches to reveal that the forearm is a cannon"). Cannons in general are a little post-Ars, never mind one built into a metal prosthetic. Normally I'd just give up and design the arm as an enchanted item, but the problem is that Guts' whole concept is based around using mortal ingenuity and iron willpower to fight supernatural beings; not only is the arm not magical in the source material, but more importantly Ars Magica's way of handling Magic Resistance basically means he can't be dependent on anything vulnerable to that. Arguably could use the "Finesse to aim" workaround for that, maybe? In general Ars Magica keeps the weapon system pretty minimal and leaves all the fun effects to the supernatural side, or else I could also have fun with the fact that enemies who aren't killed by the cannon tend to be blinded/staggered if it's used at point blank (either by the explosion itself or the small cannonball). Or I could be being silly, and maybe one of the supplements already has something I could translate into this? Fishing for ideas here too.

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I recall there are rules for giant's weapons somewhere...RoP:M or F.

As to the hand cannon, just make a Pilum of Fire with no magic behind it. If you want him to have the equivalent of a wand of pilum of fire, but with no misfires, then just say that's what it is mechanically and move on...

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RoP:F p 98

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To me one of the issues with (natural) giant weapons is that there is more to a weapon being wieldable than simply it's weight. I used to be in a dagohir group where I had the opportunity to weild an 8' long foam sword weighing about the same as my 3' long steel katana. The length difference not only radically changes the balance but a lot of other factors about how it handles, and the weapon was- even for a game where how hard you hit was largely irrelevant, useless. Secondly a larger heavier weapon is not always going to penetrate better.
Now if you want to upsize a club to a two handed club (aka unbalanced large stick) then looking at the differences between longsword and greatsword can certainly provide a clue, for example. If the weapon is magical then assign it stats based on its magical nature rather than its mechanical properties.

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I'm looking all over that page. I cannot find any changes to weapon stats. I can see a note about combat stat changes: -1 Initiative and Defense, +2 Damage. But those are from the -1 Qik and +2 Str for each 1-point increase in Size. As such, outside of likely increases in minimum Strength and Load, it doesn't appear there are any changes to the statistics for a club no matter how big it is.

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This is a good answer, and has resulted in me doing some research on what the upper bounds of usefulness could be given a character with superhuman strength but otherwise following the laws of physics, but as a more general question, I'm curious whether you have a better option for fighting something more resilient than a guy in full plate. It seems like the two main options are increasing angular momentum (putting a lot of weight behind a swing, hence the big sword idea) or combining velocity with penetration (such as through a lance charge on horseback, though my understanding is lances were highly prone to breaking). What would you say is the practical option?

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Real world penetration is about putting a lot of power into a very small area- with superhuman strength you could wield a blade that is simply heavier without being significantly longer and get more power into it, whether you are measuring energy or momentum. The other option, and the one which was pursued in the middle ages, is trying to affect the surface characteristics, essentially trying to get it to hold a sharper, more penetrative edge through more more abuse. Real world medieval anti-armor technology tended to go smaller- arrows with a smaller tip for more punch or metal bolts for crossbows, daggers which could deliver power to a point instead of along a blade- large weapons were about extending reach, especially to deal with things on horseback, and tended again to be either stabbing- spear like weapons or handled by multiple people, or with very different techniques.
For what you are trying to do I would think having a bladed staff like weapon with a heavy handle- perhaps a steel shaft to deliver more power to a halberd blade or the like would be the solution for a super-strong character. It would keep the same balance since the extra weight is being distributed evenly, allowing the character to deliver a more powerfull blow.
In game terms this kind of super-weapon will require a highly innovative smith, and can probably be handled to some degree with the weapon quality rules from city & guild, and maybe discuss with your SG about what sort of trade off should fall with increasing the minimum strength to get more effect.
For example a pole axe compared to a pole arm- the pole axe gets +1 min str and -2 spd, +1 attk, -1 def, and +3 dmg in comparison- it would seem that y increasing the minimum strength by 1 you have1 more net point to distribute amongst the other attributes, so a super-halberd requiring str 6 to wield - I would also give it a load of 3, allowing an extra point if I were the SG on this, allowing an extra 6 points in combat statistics net from a halberd. I'd probably still decrease the speed by another one because momentum is still an issue once it gets going no matter how strong you are, but it will be similar enough that I would then distribute the net effects of the rest between attk and dmg, probably favoring damage, for final stats of Init:0, attk:+7, dfn:0, Dmg+16, Str +6 load:3, then add whatever quality bonus the smith brings to the attack and damage as well.

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The angular momentum of an object moving in a circle with radius ' r ' is the product of the mass , velocity, and the radius of the circle. For a swung weapon, there are a few modifiers to the formula.

First the radius is the most complex part of formula. A weapon is not swung through a full circle and has multiple pivot points with different lengths between each pivot point. Pivot points can include the hips, shoulder, elbow, and wrist. Then you need the length of each pivot point to the striking point (sweet spot of a sword, head of a shafted weapon). Finally you have what percentage of a circle each pivot point moves through during a given swing. Due to the multiple pivot points possible, longer weapons gain the most. However this is offset by increased total weight which decreases control, recovery and speed.

Maximum usable length for "Battlefield Weapons" (two handed swung) is roughly the height of the wielder from the point the pivot hand grips it to the striking point. The actual weapon length can be even longer, including things such as thrusting points and length of grip between pivot and base hand.

The maximum usable length for "Sidearm Weapons" (most swords and other weapons that can be carried on the belt) is roughly the height of the wielders waist from the point the pivot hand grips to the tip, though are often shorter. The longer lengths of sidearms require the weapon to be sheath at an angle to avoid striking the ground, but makes them more likely to strike things around the wearer.

The mass and velocity of a weapon are inversely related. Increasing one requires reducing the other for a given motive force (the strength of the wielder). However due to mass having multiple negative effects, keeping it as low as possible is an important part of weapon design and manufacturing. The actual weight of swords (and in fact, all melee weapons) is only a fraction of what most people think they weigh.

Combining all of these gives you the angular momentum (the force of a swung weapon) which is then divided over the point of impact. A smaller point of impact serves as an effect multiplier for the strike, allowing it to more easily penetrate defenses (armor) and the target. Even bludgeoning weapons favor smaller points of impact, using smaller faces, flanges, and protrusions (spikes, studs, pyramids, etc).

The overall take away is that you want the longest weapon you can effectively wield (sidearms are capped by the need for easy carry), with the lightest weight possible to reach the required structural strength to survive use, and having the smallest possible striking surface that can survive impact. Hence even big swords tend to be as light as possible.

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With the caveat of the fact that 1) Mythic Europe physics are not real world physics, so any of the above might be tossed out the window by alternative physics and 2) even within real world physics there is a maximum speed the body can move at, such that for any person of a given strength and specific maximum body movement speed there will be a "sweet spot" that maximizes the speed and weight to get the most damage from a weapon. A super strong person who does not move their limbs faster will gain a significant advantage from swinging a heavier weapon.

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(I wrote a bunch about actual hand speed, length multiplication of it, center of balance being critical, and the oversized nature of weapons in movies and comics. If you could get a great sword down to one pound while maintaining the required structural strength, you would. Tossed it all to focus on a simple thing.)

Guts Goldenage sword weighs some 40 lbs. His Dragonslayer sword weighs 200 lbs, though some sources have it weigh 400 or even 625 lbs. Actual two handed swords of the same length as Dragonslayer weigh 5-8 lbs. These weapons also all had massive guards and pommels to bring the center of balance of the weapon close to the hand.

Even if Guts is 10x stronger than a normal human, you are looking at a sword which would effectively feel 2.5-4 times heavier to him than a great sword feels to a normal wielder. And that is using the weight given by actual bladesmiths (200 lbs), rather than the weight given by other sources (400 or 625 lbs).

Additionally even if Guts weighs twice as much as a normal human and could manage to swing that thing, the momentum of it would make it impossible for him to control. At 10x the strength and double the weight of a normal human, it would still have only a small fraction of the acceleration and deceleration a sword of its length should. It would pull him around like a rag doll. Just carrying the thing would restrict him the way a normal man is by wearing a fully stuffed rucksack.

+- + - + - +

If you are willing to use magic, a Re(In)Te effect that maintains concentration and determines what actions he is attempting to perform by his movements would allow the weapon to be used. I would go so far as saying this or a similar effect is the only way to achieve the way he wields the weapon within Ars Magica.

(Side Note: I have taken up the hobby of forging bladed weapons since my retirement from the Army three years ago. So I have a great deal of interest in historical weapons.)

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Do not underestimate @InfinityzeN's point here!
I've seen a grown man (though a slender one) moved about when he tried to use his (then-)new bo-staff. Weight 2-3 kg (4.5-6-5lbs, I forget the exact mass). He ended up giving it away to a heavier (and more experienced) practitioner, because even he realized that he couldn't control it.

Swinging a sword heavier than yourself is an exercise in loosing control of your own movements. To do so in combat is to die.

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To be fair, I didn't specify how much weight to add, aside from my re-statted glaive having one extra load for +5 str requirement to wield... and I figure ars magic physics gives some wiggle room. At least its not anime physics...

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To be fair, your answer was the most grounded attempt in the thread to that point and I was was not specifically targeting you.

When I took a class on forging a sword, the ABS master had us swing around a length of spring steel with a 'blade' about three feet long, that looked like an old car antenna. The velocity you could get with it was rather scary and the point was to teach us that weight was the enemy past what you needed for the weapon to survive use.

Compare the arming sword vs the katana. A katana weighs more because it needed more of its weaker steel to meet the structural stress requirements to survive use. Of course the Japanese finishing techniques were really top notch.

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Just watch out. Your analysis is very focused on swords even when talking about other weapons, and swords mostly developed toward thrusting when heavier armor was involved. With thrusting weapons, you can put yourself (or your horse) into it, so the sword needn't carry as much mass on the striking end. If you're not thrusting, most swords won't get through heavy armor well. And their length against armor is effectively shortened (as you mentioned), only managing their full reach on swinging with things like tip slashes and the like which are utterly ineffective versus armor. Meanwhile, you want to bring the center of mass very close to the hilt of the sword and keep the blade lighter to make things like parrying easier as well as quick changes in direction for thrusts.

Now look at non-thrusting weapons. Consider a war hammer or a flanged mace. These were much more effective swinging weapons against heavy armor. The war hammer specifically came into common use because it was so much more effective against heavy armor. Yet these are very specifically not designed with "the lightest weight possible to reach the required structural strength to survive use." Noticeably extra weight is put on the far end, moving the center of mass away from the hand and increasing their rotational inertia. They still were not nearly as heavy as many people seem to think, just as swords weren't. While your physics there is decent, this should reveal that it is a bit off.

On a related note, you may be interested in a calculation I did years ago here on just how much impact is lost if you take your hand off an axe (I think I used an axe.) just before striking (this was due to a discussion on ReTe bypassing MR). I'll have to see if I can find it.

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My break down of the force calculation in my first post had nothing limited to swords, but covered all swung weapons. Additionally "war hammers" weigh roughly the same or less than swords. In point of fact, pole arm hammers (such as the Lucerne hammer) usually weigh notably less than bladed pole arms while having better balance. These weapons were designed to put the maximum force into the smallest area possible to punch through armor. They were also far better balanced then people believe.

The only reason I moved on to things that are advantages specifically for sword design is because the "Dragonslayer" is technically a sword. But only technically because in reality it is closer to a giant metal club.

None of my data relates to thrust weapons which use a completely different formula for how they generate power. It is the calculation for kinetic energy, combining multiple velocities (you arm movement, your body movement, your mounts movement, etc) and weights (up to and including a horse the welder is riding). The kinetic energy of the target is also applied or deducted.

For thrusting weapons their individual weight beyond required strength is even more of a detriment to use then with a swung weapon. Though taking on extra weight to increase the length can and often was a desired trade off, even if it made the weapon more difficult to use. Being able to kill your enemy before they could reach you was after all a desirable outcome.

What it all boils down to was an attempt to show that "Dragonslayer" is virtually impossible to make into an effective weapon without something like magic or anime physics. In Ars Magica that is easily done with a Re(In)Te effect, though some would argue a ReTe effect would be enough.

On the related note, would that not just be effectively throwing the axe at extremely short range from a rules standpoint? Though the actually calculation would be much more complex. You have peaked my interest. While I have not (yet) forged a sword, I did make an axe. Real ones are closer in design to a modern tactical tomahawk and are insanely destructive. RMJ has a video of them dismantling a car with one.

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Yes, I mentioned that they also weigh much less that people tend to think. We both agreed on that.

But in the case of hammers, axes, and similar, you very specifically need to make the head noticeably heavier than necessary for structural integrity. This is an important part of what makes it perform differently than a sword. If you don't do this, then it ends up with a "sweet spot" similar to a sword's, which is less successful at its job. The heads were still not nearly as relatively heavy as an with an axe we use on a tree, for instance, and certainly nowhere near the ratio with a splitting maul. But the issue remains: if the calculations show that you want to make the head only light enough for structural integrity (which can be done with a pole, no head really needed outside of making a small striking surface), then something is wrong because we know reality is not behaving this way.

This is needed for swinging, too. This is what silveroak had hinted at above. If you use only momentum (angular and linear) in your calculations for a swing (as the inverse relationship between mass and velocity, though it needs rotational quantities), then you're assuming all weapons swing at the same rate while identifying that they don't because that inverse relationship requires the amount of time for the swing to be the same if the person applies the same strength. This is, for example, why we dancers, when we want to spin quickly, make ourselves harder to spin at the beginning, not easier to spin; we only switch when we're done applying the force. There are, of course, limiting factors.

If I remember right, that's what my friend was trying to argue against. The thought was that you could actively swing with ReTe right up to the moment before hitting to get the advantages of controlling the blade the whole time while avoiding the disadvantages of throwing it Vilano-style and it should cause damage more like a swung weapon. But the reality ends up much more like a thrown axe, as you point out.

Oh, apparently I actually did it for a katana since I was able to look up breakdowns on it, including a typical sweet spot, center of mass, length, and weight all in relation to each other. I also did with with a very trivial scenario (the axis of rotation wasn't realistic) which was noted to be off because I was just presenting the basic behavior to show that holding on does most certainly matter.

The katana fares worse than a typical sword built for chopping does because of the sweet spot's location so far up it. Anyway, that calculation was just to show that follow-through is an important part of the strike.

I totally agree with that. We may see it a lot in MMORPGs, anime, and the like, but those huge, disproportioned swords don't work at all in reality.

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My interest is similarly piqued. I'll do some calculations for what seems to be a reasonably ideal split of mass for an axe or hammer for a reasonably sized person. I'll have to do a whole bunch of approximations, but I should be able to model it pretty well without getting overly complex. With a real example to compare it to, it would be interesting to see. If I do the calculations on a Google Sheet, I could share that here without having to put all the calculations here, so I could focus on the explanation in writing. But I have a ton of work to finish these next two days due to sudden, huge shifts at work.

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Different weapons have different "strategies"- for example a lot of pole weapons were less about fine control and more about dropping something heavy with the assistance of gravity at a distance, and the primary attack was a downward slice. Also there were weapons that took something more of the modern SLAP round approach- which is to say that rather than trying to penetrate the armor they simply delivered enough force to the armor that the shock wave would carry through it and injure the person within, which of course was even more effective against flexible armor. So which strategy you are pursuing would probably need to be considered before you finish the design.

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Yup. War hammers commonly had two options for employing those varieties. Hammering for the shock or piercing with the other end (or hooking with it). That gave them options. I found it interesting to note that the hammering for shock method was better against thicker armor, but game designers usually seem to make thicker armor better against the hammering for shock approach.

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I'd be curious how the composition of the armor fit into that analysis. It makes sense, if you consider- even if the thicker armor reduces the kinetic energy by more some will get through, while failure to penetrate is failure to penetrate.