March 28, 2015

An exploding damage die for GURPS?

Some of the recent threads and comments about armor as dice have led me to think about alternate ways to get what I want out of Armor as Dice - less variable penetration so that if you armor rated for X (and GURPS defines X as 3.5 points per die for both penetration and resistance), and a bullet hits you with basically less energy than X, it won't go through.

Some of these distinctions don't seem like much, or important. And to a certain extent, they're very much not. If you have (say) a DR 8 bullet resistant vest, in theory it should be proof against a .45 ACP (2d pi+) but not a 9mm (2d+2 pi).


Turning to AnyDice (and we'll be doing that a lot this post) we see that the .45ACP will punch through DR 8 with 1 point or more of damage potential remaining just over 27% of the time in round numbers. The 9mm, which should always go through, will go through 58% of the time.


This is very easy to rationalize. Poor angles, uncertain coverage, and other variables make armor less certain. The tendency to treat an armored vest as if it fully covers the entire torso (a legit simplification) makes the push to make every thing just work out neatly less mandatory.


Still, players buy armor to buy protection, and some armors really are that good. The "solution" tends to be "if you want full protection in a gamist manner, buy DR6 per die of protection you want." Thus, if you want to be fully protected vs. that 2d or 2d+2 bullet, buy DR 12 and DR 14 respectively, which will increase the weight of that armor piece by about 70%.


OK, fine, but I am going to press forward and solve the non-problem anyway, because though there are many instances where you can rationalize the roll, there are others where you can't.


March 27, 2015

Advantaged Rolls in GURPS

Over at Bat in the Attic+Rob Conley thought about using the D&D5 Advantaged/Disadvantaged mechanic in GURPS, or for 3d6 rolls. Basically, roll extra d6s, and pick the lowest three.

I've written about the D&D mechanic before. More than once.

This has the beneficial aspects you'd find in D&D, in that it keeps the die roll in the usual space, but alters the probability of a given result for the better.

As you can see, in the heart of the curve, you get the equivalent of a +2 bonus (or -2 to the die roll) for 4d6 drop the highest, and +3 for 5d6 drop the two highest.

This scenario only works when you really, really want to not modify the roll. GURPS is so modifier-heavy for most things that I'm not sure this mechanic is the right fit, though it's worth thinking about when you would want to do this. One area that would be interesting would be in (for example) a hit location chart, where you might use this (or 4/5d6 drop the lowest) to deal with locations struck from an elevated or prone position.

Where else would this apply?

Grip Strength Made Easy (Easier)

Originally in Technical Grappling, Grip ST - how many dice you get to roll when you grab someone - was figured differently. During revision, it was changed, and during playtest, it was altered, folder, spindled, and mutilated.

Ultimately, I decided to go with a precise way to combine limbs when grappling. Figure out the contribution in pounds of force (represented by Basic Lift) of each limb or pair of limbs depending on bioloty, add 'em up as Basic Lift, and figure out the ST required to produce that level of Basic Lift.

The advantage here is that it didn't produce insane numbers, and it also gave a great way to figure out the grappling power applied when you're dogpiled by seven kobolds or something. Take their Trained ST, square each one, add that value up, and take the square root.

But ew. Hot mess at the table, with or without the handy chart.

+Peter V. Dell'Orto and I have looked at some of this, and found a nice solution for certain parts. But ArchonShiva over at Further Up the Spire has come up with a fast way to work it. It might not be accurate in all cases, but it's way more tractable at the table.

So go check out Manageable Grip ST in Technical Grappling and see what he's all about.   

March 26, 2015

Designer's Notes - On Target (Pyr #3/77)

Am I bound and determined to revisit and rewrite every GURPS rule? 

No. But in writing Technical Grappling, I became very taken with effect rolls, in the vein of hit points and control points. The general progression of a hit roll followed by an effect roll is familiar and favored by gamers.


Personally, I like the differentiation between skill and effect. 

Where it comes to On Target, this gestated for a goodly long time. I think it originally came from a basic unease with the Precision Aiming rules from Tactical Shooting. A series of somewhat vague, somewhat concrete misgivings with the direction of the rules, the amount of time they take, the determinism of them.

But I really did like the overall concept of rolling for extra aiming bonuses. 

March 25, 2015

Blowthrough and Armor as Dice

Apologies for references without links, but I'm behind a work firewall and for some reason they don't want me surfing the SJG Forums from work. Unreasonable folks, corporate IT. It's like they want me working or something.

In any case, there's a weekly thread that got started up over on the GURPS forums called "Tweak of the Week." It's a neat brainstorming idea, and the first one on strength can be mined for good stuff.

I was pleased to find that the second one is about Armor as Dice, a concept I embrace (and while I may have published the first Pyramid Article on the topic, it seems to be a case of parallel evolution, since I remember way back when more than one person positing this as a solution to some perceived issues.

On that same thread, +Mark Langsdorf brings up a few cognitive challenges for Armor as Dice, which I can't help with, and one issue of figuring blow-through, which I can.

So, since you roll damage and stuff after primary armor penetration, would you then have to convert left-over damage back to dice, etc., to figure out how to kill five giants, all in a row?

Dice, Dice Baby

I think the notional solution to this problem is to invoke the dice concept one more time.

Blow-through thresholds should be expressed in dice, based on the HP of the target. Ideally, a 10HP average guy would have about a 2d+1 blowthrough threshold, allowing a .45ACP to not typically overpenetrate, but a 9mm at 2d+2 will. But frankly, that's more trouble than it's worth. I'll get to it later, though, for those that care.

Ultimately, just convert mass-based HP (or just use racial average HP) to dice, and for people, that would look like the chart to the right. For a 5-ton mecha, it'd be about 6dx2. 

So just look at the armor. If you've got (say) 6dx3 DR (DR 60-65 or so) on top of a 6dx2 mech by mass, and you hit it with a 6dx6(2) projectile (say, an APFSDSDU shell), you can look at a total interference of 6dx5 (DR plus HP), halved for the (2) AD to 6dx2.5. The downrange threat is thus 6dx6 - 6dx2.5, or 6dx3.5(2). That will penetrate the armor and the HP of the guy behind it, leaving a 6dx0.5(2), or 3d(2) threat, which won't penetrate the third guy's armor, but might be a threat to human personnel.

Parting Shot

It's all about the dice, 'bout the dice.

Kidding aside, Armor as Dice is supposed to make things simpler, not more complex. You deal with dice as long as possible, and only convert to injury at the end.

The assumption inherent is that the injury is variable (and thus rolled), but the penetration is consistent enough - even through flesh and whatnot - to just treat as dice.

It should be simple, playable, and fast - though the issues such as keeping the mystery of what the foe's stats are still remain, it's designed to keep the math a bit more simple where it can be kept simple.

March 24, 2015

You spin me right round baby right round

There's an interesting discussion over on the forums about using the Slip maneuver - a retreat in the forward direction - to maneuver around your foe.

+Sean Punch provided some feedback on how this should be treated, and how when looking at a system using discrete one-second turns,  sometimes judgement must be exercised to ensure sanity.

All well and good, but as I was thinking about it, I wanted to see if one could embrace turn breaks and still preserve the same kind of feeling as Sean's method: if you get shanked in the back, it's because you made a choice.

Now Here's the Situation (apologies to Will Smith)


The situation described in the post is actually harder to bring about than I first thought it would be. But still, the basic situation is as follows, as an example of moving with a Step of 1. The actual case involved is a two-yard step, but we'll take the 1-yard case first.

First, you have two foes facing off. In this case, the orc is going to attack with his foe on the right side of his front arc.

Why not turn and face? Let's assume he can't. Maybe there's a foe in his front left hex that he wants to keep there. Maybe he just likes having his foes on his weapon side.

But he attacks, and the defender parries, and exercises the Slip retreat option to move closer to his foe, instead of directly back (Retreat) or back and to the side (Sideslip).

When the orc's turn ends, the hero gets to step and change facing, which he does.

At that point, he's technically in our staff-wielding orc's back hex . .  but he didn't start his turn there, and this is a classic case of a Runaround Attack, which is explicit on this matter: this maneuver is not a true attack from behind, from which there's no defense. It's treated as an attack from the flank/side, and is thus only at -2 to defend, rather than "you're screwed, hope your will is up to date."

The Two-Step

The case where the fighter in the blue cape has a very epic Move 11 is the contributing factor here, since it gives him a step length of 2 yards. This applies to retreats as well as forward motion (I had to look that up, but it's quite explicit on p. B377).

So this time, our defender instead of slipping to the side by one he either sideslips and then steps forward (which might not be legal, as it changes direction), or in the case of two foes face-to-face, moves through his foe. Maybe he has to evade, or he does an Acrobatic Retreat to jump over or under him.

Still, that allows, just by virtue of a defensive option, the Slip or Sideslip Retreat, for Speedy McSpeedypants to start his turn behind the orc. He can then rotate and strike.

Back Attack, or no?

In my games, I embrace the turn-by-turn nature of GURPS when I can, a lesson learned from chatting with +Peter V. Dell'Orto and playing Dungeon Fantasy with +Nathan Joy. In some of the games I played with Nate, especially, we fought huge numbers of foes. And Peter likes to remind me that that GM's job is quite hard enough already, thanks.

So if you start your turn in someone's back hex, you get a free shot at his back.

Now, it's easy to see why Sean counseled as he did. A one-turn run-around is really not that much different than a two-turn runaround. You still know someone just moved around you, and to say that if it happens within one arbitrary time span vs. another can get weird.

Sean's rule invokes player agency - always good. If you choose to leave your back to the guy, it's on you. If you don't have the opportunity to choose, you get some slack.

Rotation Station

But there might be another way to go, and that's to allow rotation at a few more spots.

Right now, in tactical combat you can change facing by any amount at the end of a move (including a step) if you use fewer than half your movement points. If you go faster, you can only change one hex-side. Sidestepping costs 2 movement points, and pivoting in place costs 2 points before or during a move, per hex-side of rotation.

I will attack, and you don't want that

Since you can change facing by any amount during your attack, I see no reason to disallow changing facing as part of your "attack," but in response to your enemy's movement. If you can take a step and rotate 180 degrees and attack (which I believe you can), you should be able to step, attack, and rotate 180 degrees.

At least forgetting the attack part, the step itself allows a free pivot of arbitrary amount before or after your step (not both!). So allowing a single hex-side of rotation after an attack, or just saying "during your turn, as part of your step and attack, you may make up to three hex-sides of rotation" might curb some of the abuses. If three hexes is too many after an attack, simply allow one.

In the case of our orc fighting Speedy, when he steps through or around our Orc as part of the parry, Eric the Orc can pivot by one hex, following his motion.

Now, Speedy's fast, and our orc will still wind up with him on his flank - but the only way Eric the Orc will wind up with Speedy in his rear hex is if he chooses to not pivot.

Parry, Block, Spin, Duck!

As part of any defense, you are allowed to rotate in place by one hex-side. You only get one retreat per turn, but in terms of rotation, have at it. This may produce many facing changes during the course of a turn.

Parting Shot

By giving the attacker and defender increased ability to rotate in place during attacks and defenses, it makes my own simplification closer in spirit - and I think easier to execute - than Sean's advice. Basically, if your foe begins his turn in your back hex, you're boned and he gets a free attack at your back against which you can't defend.

This takes the onus off both player and GM to remember what two guys might have been doing when the moves are buried within a battle that might have 30 combatants in it.

Granted, this may need some playtest to see if it's broken, but I think at minimum, allowing a single free hex of rotation after an attack shouldn't break anything.

Or maybe you treat an attack as costing half the total availble movement points, have a hex of rotation cost a movement point, so that if you have the movement left over to follow a defender as he tries to zip by you, you can do it. If not, guess you should have saved some movement.

On the defense, I think allowing a free pivot of one hex-side would be fun. I don't think it would break anything, no matter how many times it's done. But if you don't like it, you get one step and one hex of rotation on defense per turn (so you get one retreat and one rotation).

In any case, the final rule is if you start your own turn in your foe's back hex and stay there up to your attack is made . . . he can't defend against it.

March 23, 2015

Majestic Wilderlands - Do You Hear the People Sing?

Do you hear the people sing,
Singing the song of angry men?
It is the music of a people
Who will not be slaves again!

That's more or less where we left off, with the bunch of us victorious in the first battle, but winded, wounded, depleted of resources, and facing a very large number of foes of uncertain power but known quantity: lots of them.



We fade away to an inn for a moment, as Elder Carmina chats about the rebellion in Tain with the local clergy. Each person of worth is required to have a medallion to stay in town or do business, and service suppressing the rebellion is required to earn the medallion. 

They leave, passing the local shops, to arrive outside the gates of Caer Tain, within which the rest of the party is getting busy bleeding out, more or less.

In the main hall, there are several levels and a few balconies - the tower goes all the way up to the roof. We agree to clear the keep from the bottom to the top

March 20, 2015

Go welcome Chain Link and Concrete

New blog alert!

+Michael Eversberg II is blogging, and covering topics near and dear to my heart. Weapons, guns, fighting, GURPS, and he's got d20 stuff in there too.

Go check out his stuff, and you'll find longish, well thought out posts covering a lot of combative stuff.

Chain Link and Concrete. Go read it.