GUTHS: GURPS Unified Theory of Hitting Stuff

Intro: Grand Unification Theory

Why do ranged and melee TH use different rules in GURPS? What happens when a weapon is really big compared to the target? What happens when combatants are odd-sized? Does SM apply in melee? If so, how can you overcome a -15 or so penalty to slap a teeny mosquito on your arm? How can two tiny combatants possibly strike each other? Why can’t ranged weapons get a bonus for really close range? And if they can’t, again, how can tiny shooters ever manage to blast each other?

All is answered: there exists a GURPS Unified Theory of Hitting Stuff (or GURPS Unified TH System; it’s GUTHS either way). Okay, it’s not in the rules, and I coined the name just now. But this isn’t just some rules bit I’ve had posted on my site for ages, nor even much of a “house rule” at all. It’s a simple interpretation of existing GURPS rules that instantly sets all the above running smooth as a duck, 100% rules-as-written compatible. In fact, you’d assume it was the default set of assumptions behind current rules, except that it’s not, and thus the above questions remain needlessly unsolved. Unless you look at existing rules through the GUTHS lens.

The simple code

Enough of that. Here’s the GUTHS interpretation of how things get hit:

  • 1) Whether GURPS knows it or not, its ranged and melee combat actually use the same rules for TH. The core assumptions:
    • 1a) All TH, ranged and melee, uses the Size and Speed/Range table. Easy!
    • 1b) The Range column extends its mods equally in both directions, offering bonuses for close range under two yards as well as penalties for range beyond two yards (just as it was properly handled in 3e). On your 4e table, replace those dreary “+0” entries with the appropriate bonuses!
    • 1c) Range can logically be as close as circumstances allow, such as mere inches if you shoot a padlock to break it, or if you slap a bug on your arm; the appropriate big TH bonus would apply. But, when making regular combat attacks against an active target, with its movement, uncertain distances and positioning, and need for maneuvering space, effective Range (melee or ranged) can only be as close as the attacker’s SM-based height/length (two yards for a human).
    • 1d) For both ranged and melee TH, target Speed may or may not be relevant: if the target is not in combat with the attacker, its Speed generally counts for Speed/Range purposes. But if the target is engaging the attacker, it can be considered to have no Speed for TH purposes.
    • 1e) This may be a wholly new addition to GURPS combat, but it’s a logical one: when a big weapon strikes a small target, use the larger of the two as effective target size. That covers wide flyswatters hitting tiny flies, or room-wide dragon-flame jets washing over PCs.
  • 2) A couple of logical ranged-vs-melee considerations crop up, as follows:
    • 2a) While both ranged and melee attacks have an effective minimum Range (above), melee attacks also have a short maximum Range (typically a yard or two).
    • 2b) Related to the above, melee attacks face a cap on effective target size: any target size outside of a melee attack’s reach is essentially meaningless as a target, and can’t aid TH. Call that maximum effective target Size the attacker’s SM +4. (For a little more detail, that maximum might fall to +3 if your weapon is very short, i.e., Range C, or whatever the equivalent short range is for your size.)

Outcomes

From the above, the following outcomes fall into place:

Ranged combat

For ranged combat, all the above boil down to “rules as written”. Just follow standard 4e rules, using Speed (if relevant), Range, and Size (target SM) normally.

One important change occurs, though: do allow TH bonuses for Range closer than two yards, if that Range can be reasonably achieved. It can’t, for SM 0 humans shooting active targets; you should read 4e’s stance of “no bonus for Range” as reflecting that common situation.

But if a shooter can logically get closer to an unmoving target, or if a small shooter can reasonably shoot an active target from much closer than two yards (down to an effective range as close as his own height/length), do allow the appropriate close-range bonus.

This simple change makes many unusual situations – like those tiny gunmen having a close-range shootout, or a character shooting a lock from inches away – completely workable!

Melee combat

Melee, too, boils down to existing rules as written for typical situations. Target Speed is typically irrelevant in melee; ignore it, per normal GURPS melee.

Note, though, that under the above assumptions, each fighter strikes from an effective Range appropriate to his SM, at a target Size of the foe’s SM. The net result of this is the same as using relative SM as a TH mod: the difference in SM becomes a bonus for the smaller combatant to hit the larger, and a penalty for the larger to hit the smaller. Nothing changes from normal GURPS rules for two human-like fighters, but odd situations (like two tiny fighters) now work!

(Note: this relative SM rule is an official option in the 4e FAQ, thanks – at least in part – to Your Author lobbying for it from the GUTHS perspective. Though I’m sure many others have independently realized that it’s the only sensible way to handle size in melee.)

A couple of little things:

  • Don’t forget to place a maximum +4 on the smaller foe’s bonus vs the large target. (This is for melee only; there’s no cap on your ranged attack TH bonus for a large target.) 
  • Remember that you can hit small targets more easily by using the larger of weapon SM or target SM. (In other words: when chasing butterflies, use the big end of the net.)

That’s it

With those simple interpretations in place, all the initial questions about size, speed, range and TH are answered. Dwarves vs Giants in melee, ants brawling with ants, creatures of every size shooting away at each other from any conceivable distance; everything is answered and everything works.

  • A knife-fight between two Pixies? It now works the same as a fight between two humans. (Except I’d pay more to see the Pixie brawl.)
  • Shooting a padlock from inches away? Sure; it’s a tiny target, but you can take a big bonus for teeny Range. Just watch for shrapnel…
  • Need to slap a mosquito? Same deal: tiny target, but you can take a big Range bonus for having sneaked that slapping hand up close. (And use the hand’s SM, not the mosquito’s, as your target Size. Also don’t forget AoA (Determined) and Telegraphic Attack (if the bloodsucker is too busy feeding to roll a defense). In the end, it’s an easy shot with GUTHS!)

No existing rules have been mangled to enable the above effects; the rules have just been examined and made sense of. And ranged and melee TH are now unified, which is cool, because… well, just because.

GUTHS. Spread it far and wide.

6 Comments

  • Captain Joy

    tbone wrote:

    Melee combat

    Under the above, melee also continues to follow standard procedure. Target Speed typically is irrelevant in melee; ignore it. Each fighter strikes from an effective Range equal to his SM, at a target Size of the foe’s SM. The net result of this is the same as using relative SM: the difference in SM becomes a bonus for the smaller combatant to hit the larger, and a penalty for the larger to hit the smaller. However, as described above, place a maximum +4 on the smaller foe’s bonus vs the large target.

    I would add to this final paragraph: “and remember to used the larger of attacker’s weapon’s SM or the foe’s SM when determining the larger foe’s penalty vs the smaller target.

    You might also add that the +4 maximum assumes the small foe has a weapong that extends his reach beyond 1/2 his size. So, if the smaller foe has no way to extend his melee attack range, e.g. punching, biting, a small knife, then a +3 maximum is more realistic.

    I know I’ve said it before, but *fantastic* stuff T-bone.

    • tbone

      Ahoy, CJ. Thanks for the very kind message.

      I’ll make the suggested addition re using larger of weapon SM and foe SM.

      And as for the max SM + 3 vs SM + 4: Unless I’m mistaken, this isn’t part of the “official option” in 4e, which just offers a flat SM + 4. You might be referring to the original GULLIVER write-up on the topic, where I suggested a max SM + 2, or SM + 3. Since the 4e official option chose a +4 instead, I went with that in GUTHS, for compatibility.

      With a nod to my original rules, I’ll add a compromise in 2b): a flat +4, or a varied +3 to +5 depending on attacker Reach. I think +5 is getting awfully generous, but it all averages out to to the “official” +4, and should work fine in play. Look OK to you?

      • Captain Joy

        tbone wrote:
        And as for the max SM + 3 vs SM + 4: Unless I’m mistaken, this isn’t part of the “official option” in 4e, which just offers a flat SM + 4. You might be referring to the original GULLIVER write-up on the topic, where I suggested a max SM + 2, or SM + 3. Since the 4e official option chose a +4 instead, I went with that in GUTHS, for compatibility.

        With a nod to my original rules, I’ll add a compromise in 2b): a flat +4, or a varied +3 to +5 depending on attacker Reach. I think +5 is getting awfully generous, but it all averages out to to the “official” +4, and should work fine in play. Look OK to you?

        I think +5 is too generous. Maybe just add a parenthetical: “(although a +3 is probably more realistic for reach C weapons)” or something like that.

        • tbone

          My preference would be to keep my original, old +2 as the simple, all-purpose maximum for all weapons; and for more detail, sandwich bonuses around that: +1 for really short weapons, +3 for really long, +2 for everything else.

          But since Dr K decided upon +4 instead, that makes detailed sandwiching hard: +3 for short, +5 for long, +4 for everything else. And we agree that +5 is just sounding too big.

          Oh well, if sandwiching around +4 doesn’t work so well, I guess the next best may be as you suggest. I think I’ll work that in. (And anyone reading these comments can pick up alternate ideas to try.)

          Thanks!

  • Esteemed Visitor

    Aw, by the title I thought it’d be “Unified” as in joining To Hit and To Defend on a single roll…

    Well, a man can dream :C

    • tbone

      Hmm, that’d be the GURPS Unified Theory of Hitting And Defending (GUTHAD)…

      Single-roll TH and defense? I’m not interested myself, but there are plenty of examples in other RPGs; HERO System is one. For GURPS, I imagine it’d have to work something like a Skill roll, plus a big bonus (+10 or so?), minus the target’s AD. I’m pretty sure I’ve seen people on forums discussing such a mechanism… Whatever the negatives, I’m sure it’d play pretty fast!

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