The occasional silliness of Dodging lasers

I got to play GURPS at TL9 this past Saturday, with +Jeromy French , +kung fu hillbilly , +Alina Cole , +Carl Miller , and +Matt Sutton .

We got into a battle with lasers and slugthrowers. There was an awful lot of successful dodging going on. Some of this just “the dice say what the dice say.” But after a bit, you could tell from the body language (and post-game conversation) that the overall assessment of that was “no frackin’ way.”

GURPS has a fairly realistic outcome level when it comes to gun battles. The real level of hits in combat at ranges spanning a mere 3-10 yards is something like “less than 10-15%.” If you figure GURPS Dodge scores on the order of 6-10, (15-50% chance of a successful dodge), you’re still looking at “attack” level percentages on the order of no more than 30%. That’s 8- or 9- at best net/net, even before dodging.

So at 3-10 yards (-4 down to -1) skill levels are presumably in the 9-13 range (not spec ops, from “joe average or a cop who doesn’t do much range time). Again . . . realistic. Most of these exchages involve considerable fear and andrenaline, and sighted but not aimed shooting. See GURPS Tactical Shooting for how these differ.

Given “on the range” bonuses of something like +6 to +8 for knowing range, not being in any sort of danger, no stake in the outcome, etc, that’s likely looking at range-level accuracy on the order of 15 to 21, plus Acc 3 of the gun. Net raw score is likely 17-24, meaning that on a quiet range shooting once every second or two, you can probably put every shot on the paper (at a raw skill of 9) to being able to eat a -6 penalty to put 90% of all your shots in a 0.2-yd circle: every shot in an 7″ circle.

When I took a range accuracy test in Texas years ago, shots from 3-25 yards were all within 6″ of target. I’ll admit it (Texas rules apply – if you can do it, it ain’t braggin’): I’m a good shot on the range. You might also call much range shooting Guns (Sport) and hit shooters with an additional -3 in real combat situations unless they’ve been on live-fire, shoot/no-shoot, or kill house training.

And yet . . .

Lasers. There’s no recoil to deal with, unless you’re ejecting a chemical cell. If you can put the red X on the target and pull the trigger, they shouldn’t get to dodge. They just take it. Beam spread is certainly not appreciable at the kind of distances we were facing.


DECIDE . . . and quickly

Well, one possible thing to do is steal from T-Bone: use his DECIDE rules where you declare your defenses before you know if a blow hits. That means you have to declare defenses before the to-hit roll is made, or sometimes you can do it retroactively at a penalty (but not for lasers, he clarifies).

There are ways to tweak this, such as if the defender succeeds, you still roll to-hit, fishing for a critical.

You can also do something like this:

Evasive Movement (a sort-of variant on All-Out Defense)

At the beginning of your turn, you may declare you are moving evasively. You’re bobbing and weaving, moving side to side, up and down, etc. You can take a certain penalty to all your actions on your turn, in exchange for inflicting that same penalty on your foes’ ranged weapon attacks. This has zero effect on your foes’ incoming melee attacks (but still penalizes you!). The maximum penalty you can voluntarily accept is (say) how many yards you actually moved this turn, plus your Basic Speed.

I might need to divide that by two. So if you have Basic Speed 6 and have moved your full 6-yard allotment  the best you can do is take a -6 to your own stuff and -6 to your foes.

Maybe I even need an exchange rate. You can inflict up to -6 on your foes, but you take -12. You may be disrupting everything you do, but it’ll be easier for your foe to plug you than it will be to shoot him while doing the crazy dodge and zigzag thing.


I have always liked the logic of DECIDE, but the all-or-nothing of the attack/defense sequence, even when you declare first, bothers me. There’s an argument, and not a bad one, for allowing Prediction Shot (-2 to hit for -1 to penalize Dodge for ranged weapon attacks) in realistic games. It’s in GURPS: Gun Fu, probably among other places.

Yes, both Gun Fu and Tactical Shooting were written by +Hans-Christian Vortisch. He’s just good that way.

Still, a nice way to split the difference is to reverse it. Use DECIDE, and make the defender choose his decision first. But . . . apply double the margin of success of the Dodge roll to the to-hit chance. A critical success on the defense roll means your foe must fire, and always misses (though might hit someone else). But any other result only alters the to-hit penalty. A critical success on the attack roll obviates any penalty from the defense except a critical, which has primacy of place. This favors defense over attack in this case, but since defenses are usually so very much lower than attacks, I’m cool with that.

I think I like DECIDE + Blended.

You’re shooting a laser at someone. They can’t react to the fire after they know it hits; they must choose whether or not to defend (nearly always dodge). If they roll vs. their Dodge-9 and get a 6, making it by 3, then you take -6 to hit. If you miss, you miss. If you hit, or hit with many shots, so be it. But they have to declare the defense (and suffer the consequences for things like Dodge and Drop) ahead of time.

[Note: I clearly have a rodent living in my wall, eating away at my insulation. It is distracting, and will ultimately be expensive. Sigh. I can hear the bastard chewing away.]

The decision order and how defenses only need be rolled on a successful hit raises eyebrows for nearly everyone. I can see why it’s done; why drive extra rolls on a miss? But for people with sparring, combat, or any kind of experience with fighting, it always strains, sometimes breaks, suspension of disbelief.

I think there are fixes to this that won’t burden the GM or players, but will help with the “yeah, that makes sense” factor.

Might result in some dead PCs, though. Better hope you took Luck and its variants.

Seeing It Coming

After I posted this, I remembered something. GURPS appropriately doesn’t allow any defenses against stuff you can’t see coming. So in order to actually be allowed to make the DECIDE roll:

  • If you’re defending against someone you’re actively attacking or aiming at – you get to make the  call, no problem. Just DECIDE.
  • If you are not engaged in an Aim or other “stare at someone” action (Wait, Evaluate, for starters) you should probably be able to make a modified Perception roll to see someone bearing down at you. 
  • If you are actively focusing on someone, then your Per roll is modified severely downward for tunnel vision. 
For the second one, you can probably take a general “Evaluate” that says “I’m looking for threats” that gives a bonus to the “does anyone draw a bead on me?” roll, but doesn’t give the usual Evaluate bonuses for focusing on one guy.
Note also that Tactical Shooting has actual playtested rules for situational awareness that certainly must apply here!

8 thoughts on “The occasional silliness of Dodging lasers

  1. Why not just give a defense penalty to lasers?

    Otherwise, you really need to invert the whole order of combat rolls for all combat. Say, -2 to Dodge.

    I'm not really sure lasers would really be so much more accurate in actual firefights – most of the same factors apply to initial shots (sighted not aimed, nervousness, timing of the trigger pull vs. where the target is, your own vision and confusion, make of the gun and how well its targeting laser orients to the killing laser, condition of the gun, etc.).

  2. Penalty to Dodge is one way to go, and has the simplicity appeal. IF you hit, dodging line-of-fire is harder.

    T-Bone argues that inverting the order of combat rolls is no big deal, and based on my experience with online gaming with Tabletop Forge and MapTool, I agree. We roll – some using macros, some typing away on the command line – for hit and often "does 13 cut damage, if successful."

    Doing hit declare, defense declare and resolution, hit resolution or hit declare, defense declare, hit declare, defense resolution would be a change, no doubt, but I don't think it would have too much impact in difficulty of rules comprehension.

    Once again, Peter, your thoughts have occasioned another future post. Thanks!

    1. I just hate inverting the rolls, because it adds ones you don't need to actually resolve. Rolling defenses before I roll to hit is like rolling damage before I find out if I hit you or not – it better do something really useful for the extra die rolling and tracking it will entail.

    2. I like rolling all at once. with 6 + D dice, divided into three groups differentiated by color.
      The black three roll to hit
      The white three roll random location
      The red ones (however many there are) roll damage

      To me it is one physical action and can all be determined at the same time. Sure, some of it won't apply. If I crit fail on the to hit roll I don't need the hit location or damage roll, but then again, the GM can use that info to make an interesting story out of the results. e.g. You miss his foot so badly your sword sticks into the ground -or- You swing right into his shield with so much force your sword leaps out of your hand.

  3. For lack of time, I've cut out far more gaming-related reading than I'd like… but D Cole has a blog? For this, I'll carve out time.

    I tried to say as much a week ago or so, but the commenting system isn't letting me in, at least when I attempt an OpenID URL. Before making any comment on topics at hand, let me see if I can get this through…

  4. Hm. Looks like the no-log-in problem was my browser (Safari); Chrome+OpenID worked. Haven't seen that happen before.

    Anyway, I like your shot at evasive action rules; it's a topic I'd thought about a little way back, but never did anything with. Off-hand, the only thing I might suggest adding is this: That crazy bobbing and weaving doesn't sound like it'd be too good for actually making quick distance. Should the degree of weaving also subtract from your Move? Perhaps in a 2:1 ratio, so that with Move 6, you can give the foe up to -6 to hit you, while you suffer (possibly) -12 on your actions, and take -3 on your actual Move. (I'd also assume that any such evasive action disallows sprinting.)

    It makes for an interesting defensive dynamic: Sprint at full speed to reach cover quickly, while creating a higher Speed-based TH penalty for the foe? Or bob around at a slower speed, to create the evasive action TH penalty instead, even if it means a lower Speed-based TH penalty for the foe and reaching cover more slowly? Ah, decisions…

    Also, perhaps the best evasive action penalty you can apply should be the lower of your Move or your Dodge? That way, a creature with high Move but poor Dodge (elephant?) can't get all that bobby and weavey…

    Finally, a note on DECIDE: Not sure what you're referring to by the "all-or-nothing" aspect of the rule, but in any case, I'd like to clarify for you and your commenter that inverting rolls, or messing with rolls at all, really isn't part of DECIDE. The concept is simply this: When the defender needs to make the decision to Dodge gunfire, he needs to do so before he *knows* what the TH roll was or will be. The TH roll itself may have already been made in the normal fashion, or may be made immediately thereafter; the GM is free to do it any way he likes. The result just has to be kept hidden from the defender (like a hundred other GM rolls) until the defense decision is made, as the TH result is something the PC simply couldn't know in advance.

    Thus, there's no need to roll and resolve defense before TH, or otherwise add a single extra roll. You can play it simply like this: The GM says "The Nazis open fire!", you say, "I Dodge! (or jump for cover, or take evasive movement, or whatever)", and then the GM checks TH in the normal GURPS manner. If the bullets "hit", then you check Defense, again in the normal GURPS fashion. (DECIDE's only difference from GURPS RAW: If it turns out the Nazis had poor aim and missed where you were, well, you sensibly jumped for cover anyway. That's the point of it all! : )

    1. tbone: Welcome!

      Some good suggestions as to the max value of evasive movement; basing it on Dodge makes good sense.

      My only thought on lowering Move is this: due to the perceived need to act every single turn, the GURPS battlefield is darn near immobile. The odds of working your way close are pretty low.

      The need to roll defense before TH was an outgrowth of my thought of applying the defensive margin as a penalty to the to hit roll. I find it more sensible to roll defense first, largely from a narrative flow point of view.

      I'm going to shoot at him.
      He dodges; he's really jinking around (he rolls), and you're at -6 to hit!
      No good; I don't fire (or he fires anyway).

      You could also "force" the attack to shoot (he declared it), and only avoid shooting if he makes an IQ or Per-based Guns roll (I'd allow Precision Aiming check if you have it).

      Anyway, more later. One important (to me) aspect of DECIDE (with or without roll inversion) is that if using the Action Point rules for short-term fatigue, it will make the defender spend them getting out of your line of fire on every shot, rather than every hit.

    2. You're right: for the evasive action mechanism you describe, if the penalty to attacker TH is based on a Dodge roll, then it does sound sensible to check Dodge before TH. And I like that: if some action has to logically take place before another action, I like resolving them in that order too. (Although, unless I misunderstand, it shouldn't be *necessary* to roll defense first. You could roll TH first, and if it's a clean RAW miss, then the degree of extra TH penalty from evasive action is moot. If it's a clean RAW "hit", then you'd roll Dodge to see whether the resulting TH penalty negates the provisional hit. Is that a correct understanding?)

      In any case, I just wanted to note, for any readers, that DECIDE by itself does not require a change in order of combat rolls (or any extra rolls). All it says, in a nutshell, is, "Hey, if you want to dodge freaking gunfire, you need to either do it or don't do it, regardless of how that TH roll is going to work out." That's it. That one little change, I think, makes GURPS' "anyone can dodge gunfire" assumption a perfectly agreeable one!

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