I love the Size-Speed/Range table in GURPS. It’s a logarithmic progression where every six steps is a factor of ten in magnitude.

Every time I used to look at a scaling issue, I’d try and work it, and work it, and work it . . . and in the end, I’d realize that the answer was within me all along, like the answer to the question “Who is the master?” from The Last Dragon. (Come on, you saw it too: “…there is one place that you have not looked and it is there, only there that you shall find the master!”)

The Last Gasp? I struggled to find the right progression for how long-term fatigue recovered. The best mathematical solution I found was to use the progression for the SSR table so that each FP recovered at basically 1.5x slower than the FP before. Every single FP accumulated was worse than the last.

Steven (Marsh) came up with the suggestion that it was too complicated as-is (true), and that levels of fatigue, rather than a continuous progression, would be more playable (also true). But mathematically, boy was the SSR-based table pretty.

You can also do some really fun work extending the Size table when it comes to shooting things at large and small creatures and objects. David Pulver did something like this in his Eidetic Memory column on Extreme Damage. Personally, I’d use the Size-Speed Range table for both size modifier and bullet sizes, and just let them interact naturally. I have a SJG Forum post on this somewhere; I’ll have to search for it, but I did this, and it worked well enough. Both are good solutions to the same problem: Age of Sail warships didn’t exactly disintegrate after receiving one broadside (they can do so in GURPS), and some creatures are large enough that firing lots of low-power bullets at them will just piss ’em off, and do very little real damage.

Anyway, wherever you encounter a scaling issue, be it weapons, powers, etc., the table provided at the core of GURPS is a great place to start.

I hope everyone had a safe and happy New Year, wherever you are.

I made good progress on a very stubborn project (actually, several of them, one was not gaming related) yesterday. It’s amazing what staring at a blank piece of paper will do sometimes.

Looking forward to this year in gaming. I hope to see publication of GURPS Martial Arts: Technical Grappling, and I have a few concepts for Pyramid articles that I’d like to set down. I also have a mental thought about another book-length project or two.

Continuing, I hope, will be the Dungeon Fantasy game I play in, and another GURPS game will be starting up with the group I currently play Pathfinder pirates with. It’s interesting and cool to use the online video and chat technology to game with people all over the world.

But that’s the subject for another post.

I love tinkering with rules and mechanics. The things I’ve published have all been basically tweaks to the rules and mechanics of GURPS. I did do one for Frag, once. (Huh . . . all my old articles are available as free samples. Weird.)

But why? The system is pretty darn cool as it is. It’s a freshly-cut Christmas tree, and you can put whatever lights and ornaments you want on it. You have to choose carefully, though. The box of stuff that comes with GURPS will overload any tree. And you’ll lose the specialness of a particular arrangement if it’s ornaments and glitter crowded and overlapping from base to star.

And yet, I write rules. Some of them are really complicated. Some seem that way, but are pretty workable in play.

I write rules in service of narrative. No, really. Why else would you do it? The old Star Wars RPG by West End Games was (and is!) one of my favorite treatments of Star Wars. Ever. It took five minutes or so to make a character (just pick out a template and assign the dice pool the GM gives you), and was able to help steer stunningly playable narrative that just felt like Star Wars. You just needed a ‘blaster,’ or maybe if you were badass, a ‘heavy blaster.’ If you wanted to call it a DL-44 Heavy Blaster Pistol, well, fine. Who cares? Much like Episodes IV-VI, it was all story, flash, and fun, and point-five past lightspeed and stupid comments about making the Kessel Run in less than some number of parsecs. And Han shooting first.

That didn’t mean they didn’t publish weapon, gadget, and especially starship expansions. They did, and I greedily consumed them. But mostly it was flash, and the most fun was had with my group back in college (with me as player) and in grad school (this time as GM) was heavy on plot, and a lot of “roll and shout.” And whip out lightsabers. Any game is made better with lightsabers.

OK, enough Star Wars – but how can someone as detail oriented as I am just love the hell out of such an almost aggressively non-simulationist game? Expectations. For a grounded/realistic game, you’re going to want to ensure your players’ expectations for a believable outcome do not clash with what the results of the game mechanics bring. The outcome must be plausible, believable (not necessarily realistic), and rare events must be, well . . . rare. Or at least something that happens due to good planning (like the nifty rules for “Tactics Re-rolls” on GURPS High Tech  p. 60 of GURPS Martial Arts) or the various versions of luck, such as Destiny Points from Monster Hunters or the Advantage of the same name in Basic.

So the bow design rules were targeted at having a weapon of choice for punching through armor be a gun, not a composite bow. It was not hard to match Strongbow, Arm ST+2, and a Composite Bow with (say) ST 13 to have an effective ST 17 and thr+3, for 1d+5 damage . . . about as much penetration (and injury, though that bothers me not at all; arrows are nasty) as a .40 S&W.

The Last Gasp came from a desire to have lulls and flurries in GURPS combat. But I wanted it playable, so my first thought was “you have to spend a point every time you roll dice.” That didn’t quite work out, but what did come out – Action Points where most normal actions were 1 AP, “All-Out” actions were 2 AP, and various other actions were fairly simple – is intuitive enough that everyone who’s tried it (and written me back to comment) has enjoyed the feel. Once I had Action Points, though, Fatigue Points needed to recover more slowly. That, however, is worthy of its own post.

Technical Grappling? That one was inspired by a desire to have the quality of a grapple not be fixed (currently, a successful grappling attack inflicts -4 DX. Period.), ensure that strength was restored to it’s real-world importance, and allow grappling matches to have all the wonderful color and flavor that hand-to-hand striking and armed combat currently enjoy thanks to Sean and Peter’s GURPS Martial Arts.

What does that have to do with expectations? I studied Hwa Rang Do at the Minneapolis Academy for about ten years. We did serious grappling for eight or nine of them. And the rapidity and finality of “you’re grappled, you’re Arm Locked, you’re crippled” that fell out of certain applications of the existing rules just wasn’t right for reality, and strained suspension of disbelief in any realistic game. Not all grappling combats go like Black Widow taking on a bunch of guys in Iron Man 2. So I came up with an idea. That led to more thoughts. Then a system. Pretty soon, I had enough that I wanted to do a proposal, and after some back-and-forth emails, I had a contract.

So: Whom do I serve? I serve storytelling. I serve telling a believable narrative that allows (but never requires) people to have their characters enter the story in a meaningful way. Granted, I’m a geek with a rather technical background, so frequently that means math as the basis for what I do. I collaborate with people who smack me around when that math needs to be done mid-play, though.

Keeps me honest. We all need that.

I speculate that GURPS (and maybe The Fantasy Trip; I wasn’t around for that one) started with a fairly generic view of damage that incorporated penetration, blunt trauma, injury, and a certain amount of gamist fun. GURPS High Tech introduced the dependence on the square root of kinetic energy as a “damage” scale by giving the general rule of 20d = DR 70 = penetration of one inch of armor steel. I’m not sure from whence that one came, but I suspect David Pulver provided it to Mike Hurst

All of a sudden, you had two different progressions for damage, and some projectiles (bows) were on the ST-based scale, while the more-easily-quantified set (guns) were on another.

Sometime around the year 2000, I started fiddling with Excel’s solver. I thought that if I could find enough penetration data, I should be able to take a priori data about projectiles (specifically bullets) and turn that into GURPS stats. The result got me a mention on TV Tropes (look for Arbitrary Gun Power), and was published in 2002. But it worked fairly well, and got me noticed by a few other gamers

Anyway, THAT little adventure got me to notice that while firearms matched penetration of armor with known and quantifiable data – in this case the mass, velocity, and caliber of the bullet (from which you derive kinetic energy and momentum – that and cross-section are all you need to derive basic damage/penetration and a wound channel size modifier), weapons on the melee scale (things that you look up as “thr+2” or “swing+3” on the Damage Table on p. B16 of GURPS Basic Set, Fourth Edition) got pretty high penetration numbers pretty fast. Maybe too fast.

I once again scored a mention in TV Tropes by nearly breaking my brain (and Steven Marsh‘s sanity) figuring out how to do for bows and arrows what I did for guns. It was phenomenally more difficult. 

OK, so I’ve covered arrows and bullets. What about sling stones? Swords? Maces? Polearms? Pointed sticks? 

Um . . .

My previous post was an attempt to show how you could at least get the scaling of melee weapons right, where every doubling of ST also doubles penetration.

What you say?! GURPS ST measures applied force, and it goes as your ST score squared (Basic Lift is measured in pounds of force). Energy is force times distance, and if distance is more or less related to how far you can move your body (push-pull-twist-turn!), then doubling force should double deliverable energy, quadruple force is quadruple energy, etc. Then when you put this on the same sqrt(KE) progression as guns, you can arrive at a nice progression where ST 10 is about 1d, ST 20 is 2d, ST 40 is 4d, etc.

Hey, that’s damn playable. Even for me.

Well, that’s penetration, great. But injury? GURPS as-is is probably more right than wrong here when it comes to squishing meatbags. People are notoriously fragile (and strangely and unpredictably robust as well). 

So then you get into wounds, penetrating trauma, blunt trauma, and other things.

Fortunately, GURPS already has the tools required to handle this.

It has a basic damage number that should be used to represent penetration.

It has damage type and damage size modifiers that I’d personally apply a bit differently (maybe that’ll be Part 3), but basically are a “wound channel severity” modifier. 

It has armor divisors to represent something that penetrates better (or worse) than the raw energy might otherwise indicate.

With those things in mind, the only thing that’s really missing is a better way to represent blunt trauma and other non-penetrating injury.

Were I to start from scratch, I’d try and figure out:

Penetration rating, probably mainly based on energy. This would be GURPS’ “basic damage,” but possibly on a new scale. I like the “ST equivalent” number from the last post, since many weapons just act as lever arms, multiplying force. Multipliers are also nice because they allow the quite-simple “add +1 per die” type math, which is even easy in play.

Blunt Trauma rating, probably based on momentum and impact force. I think this is mostly what is done for hand weapons now, implicitly.

Armor Penetration modifier based on shape, hardness, or other factors. This is the source of my assertion that impaling weapons (a damage type I loathe) should probably get a (2) armor divisor, due to all their force being concentrated on a tiny, hard point.

Wound/Injury modifier based on the size and depth of damage. If I were really good, you’d incorporate some sort of “you have to achieve so much penetration before you can get to a Vitals type location.” That would help scale certain effects where you really NEED to go deep (Giganotosaurus hunting! Or a Frumious Bandersnatch)

I’d also have blunt trauma (including punches) be resisted by a HT roll, possibly influenced by skill. During the writing of The Last Gasp, one of my helpers ran a boxing match, and we decided that a HT roll to avoid actual HP of damage (but preserving the AP loss damage causes) from punches would make a LOT of sense, since even with boxing gloves, a typical 15-round boxing match as played in GURPS would kill both fighters. Extending this to all blunt trauma wouldn’t be too much of a leap, and if there were a penalty to HT rolls based on the rolled damage or something, that would keep maces and staffs scary. Alternately, padded hands might do the trick for bonuses to HT. People CAN get killed in fights, after all. They just usually don’t.

None of this is to say “GURPS is broken, wah!” It’s the best playable simulation out there that you can nod your head and say “yep, I get that” for most things. But when the tool of choice for penetrating DR 8 plate armor is “give me a sword” rather than “give me a spiked warhammer” (this one, not that one) or “grab me my gun,” then some head scratching might be in order!

The key in all this is to keep it fun and playable. All this crap needs to be subsumed into a table and calculated but once, during character generation or on obtaining the item the first time, and then never again. Even as ugly as The Deadly Spring was, the math is all in a spreadsheet (generously provided by Steven along with the issue of the magazine!) done up front.

Over at the GURPS Forums, there’s a really interesting (well, interesting to me) thread asking the question if basic melee weapon damage is too high (what you look up on p. 16 of the GURPS Basic Set).

I think the answer is “yes.” In fact, as part of my “Armor Revisited” article I had originally written about a page explaining why, how, and how I’d fix it. But I cut it out since it opened up a few cans of worms, potentially, that didn’t need opening.

Still, it was Just Sitting There, so I posted it on the forums, and now I post it here (this will make my musings in Part 2 of this topic a bit more cogent, I hope).

I note that JCurwen3 posted that he used it in his games, and finds that whatever cans were opened, they might have been more Whup-Ass than worms.


Rescaling Melee Weapons

While firearms are explicitly on an energy-based scale that doubles penetration for every quadrupling of energy, melee weapons do not scale this way, and the raw damage rises much faster, making high ST unrealistically effective when applied to hand weapons and muscle powered ranged weapons.

For an alternative take that scales the same way as firearms, consider rescaling thrust and swing damage. A cinematic scale would have thr equal to ST/10, and swing equal to ST/5; a more realistic one might have thrust as ST/20, and swing as ST/10.

Oddly Small Damage Increment Table

Roll one off-color die, and adjust the number rolled to the table value. The Notes entry shows where rules of thumb can be used to more quickly interpret the roll of the odd die. Each entry is scaled to give an average result consistent with a fractional d6.

Roll on 1d6
Dice Average Damage 1 2 3 4 5 6 Notes
0.1 0.35 0 0 0 0 1 1 1d/5, drop fractions
0.2 0.7 0 0 1 1 1 1 1d/5, round normally
0.3 1.05 0 1 1 1 1 2 1d/4, round normally
0.4 1.4 0 1 1 2 2 3 1d/2, drop fractions
0.5 1.75 1 1 1 2 2 3
0.6 2.1 1 1 2 2 3 3 1d/2, round normally
0.7 2.45 0 1 2 3 4 5 1d-1
0.8 2.8 1 2 2 3 4 5
0.9 3.15 1 2 2 4 4 6
1 3.5 1 2 3 4 5 6 1d6

Implications for Play

Using the “realisitc” scale with ST/10 for swing damage has many repercussions, which must at least be considered before adopting these rules.

Devalued ST

ST is “the attribute that you use to buy damage” in GURPS, with a healthy side-order of “lifting heavy stuff” and “more HP.” The realistic scale requires ST 20 to do 1d thr and 2d sw, and probably calls for a price break. HP are 2 points each; Lifting ST is 3 points per +1 ST, and Striking ST 5 per +1.

HP and lifting are as valuable as ever; reducing Striking ST to 2 per +1 ST in realistic campaigns, with overall ST at 7 points per +1 ST, seems appropriate.

Hand Weapon Damage

Weapon damage is lower, and thrust weapons in particular will have limited penetration capability. This takes what was the historically preferred method of punching through heavy armor and nerfs it further. To compensate, add a (2) armor divisor to weapons with a sharp, narrow penetrating surface. Consider optionally allowing a still more impressive construction, buying a fine (hardened) penetrating point that gives a (3) for ¥4 cost. This would not be available for arrows (see The Deadly Spring, Pyramid #33, for suggestions concerning bows and arrows).


With most hand weapons using the realistic scale, personal armor just got a whole lot more valuable at low DR, especially using the revised armor weights from GURPS Low Tech. This isn’t a bad thing; in fact, it might make a campaign world more closely resemble what we know about our historical real one . . . on didn’t need to lather on 80 lbs. of mail, leather, and plate to protect against basic cuts from swords, or long-range shots from flight or hunting arrows.

Character Differentiation

With thrusting damage at ST/20, and swing at ST/10, there will be very little differentiation between average, fairly strong, and even very strong characters. Weapons rated at sw+2 or sw+3 (maces, axes, and falchions, for example) have their damage almost all defined by the weapon, not the user.

Consider treating the “adds” as an indicator of the power of the lever arm being applied. Treat each +1 as adding +1/3 to a ST multiplier – a sw+2 weapon instead multiplies ST by 1.66. A ST 14 warrior swinging a falchion (sw+2) will do damage as ST 23.2, or 2.3 dice.

One would thrust using the same calculations: a short spear thrust by the same warrior for thr+1 imp would multiply ST by 1.33, for ST 18.6; damage would be ST/20 (2), or 0.9d (2) imp. Note that same spear using the Damage Table (p. B16) would do 1d+1 imp, an average of 4.5 points of penetration. Even the realistic scale here will do 6.3 points, thanks to the armor divisor.

Coup de Grace

The changes to melee damage on the realistic end would bring GURPS damage on the hand-to-hand scale more in line with firearms damage. For a character to do as much damage with a punch as with a 9mm pistol would now require about ST 52 . . . well into supers territory. Even a strong character with ST 20 (1d thr) will be out-penetrated by a .22 LR (1d+1 pi-). For those who want a more realistic scaling for penetration, this may be more satisfying.

Today while doing a home improvement project I had occasion to walk around the house with a dueling version of the venerable “Ten Foot Pole” from Dungeons and Dragons.

Well, not too much – the pole was nine feet long.

Boy was it a pain in the butt. My basement has ceilings that range from seven to nine feet, with nine being the distance, MAYBE from concrete to up inside the joists.

But to wander around with such a thing? In anything resembling a real dungeon? Icky and annoying.

Heck, I self-imposed this on myself while playing Cadmus, my character in the Pathfinder-inspired GURPS Dungeon Fantasy campaign I play in on Tuesdays. He’s an axe-and-shield guy, but I wanted him to also be skilled in a long weapon, and so I chose a dueling poleaxe, with spear, hammerhead, and pick. But realistically, a Reach 2,3 (6-9 foot beyond the 1-yard hex he’s standing in)  weapon is just unwieldy. I kept making jokes to the GM about “can’t I have one of those Highlander polearms, that you can just procure out of nowhere and that doesn’t encumber you at all?”

GURPS gives Bulk ratings only to ranged weapons; Holdout penalties in the Basic Set come close, but top out at -6 for a “heavy sniper rifle,” and a bastard sword is -5. A longbow, which is going to be six or seven feet long, is -8. I came up with a formula (as I always do) for Bulk as a function of length for The Deadly Spring (my article in Pyramid #3/33) making Bulk equal to 9 – 9*log(weapon length in inches). If you have a crossbow, add the length of the bow-part to the length of the stock. So a 9-foot pole is -9, and a 10-footer is -10.

If you apply this (or some fraction thereof) as a penalty to DX to move around with the damn thing, especially in a hurry, well, given how many times I banged it into the ceiling, it reality checks well.

First blog post!

Why will anyone care? Mostly, gaming stuff. I’ve got a few things in Steve Jackson Games’ Pyramid, one “real” e23 supplement on the way as soon as the Big Damn Ogre gets out of the way of the publishing queue, and it’s Just Fun to muse about games.

Bear with me as I get this blogging thing figured out, and thanks to Dungeon Fantastic for leading the way.