Dodgin' Bullets

[Andreas]

Originally Posted by HANS

The problem with this, again, is that Dodge for firearms does NOT involve dodging the bullet. The speed of the projectile (or laser beam) is completely irrelevant. You dodge the line of sight of the shooter, really. You dodge his presentation (his aim). You move erratically. Again, all the discussions about the velocity of the bullet miss the point. The reason is that we KNOW that you cannot dodge a bullet by seeing the projectile and moving out of its way. However, we also KNOW that you can dodge the presentation and that you can make hitting yourself more difficult. That is Dodge. I concede that the terminology might be flawed, as it lumps it together with dodging things that you can, actually, evade this way (baseballs, spears, 40-mil grenades, etc), but it works.

Cheers

HANS

The rules I'm referencing in the Dodge This article are rules for spotting the projectile and dodging it. It is true that it is generally not possible to dodge bullets like that, that is why I'm saying that the penalties are way too low.

However having such rules rather than declaring it to be impossible to do anything but move erratically and hope that the attacker misses makes sense. There are attacks that are slow enough to be dodged like that (such as thrown rocks) and there are plenty of people in fiction who are fast enogh to dodge bullets. You just need to make the penalty for dodging bullets large enough that realistic humans can't manage it under nomal circumstances.

[DouglasCole]

Originally Posted by Andreas

The penalties Dodge This assigns based on the speed of the projectile seem very small. An attack moving 2000 yards/second only give a -4 to dodge even though that is too fast for a human to be physically capable of moving out of the path of the bullet unless the attacker is very far away. Even an attack moving at light speed only gives a -12 penalty...

Also what is the reasoning behind only having a half as large penalty to dodging as the penalty for parrying or blocking? Dodging is generally easier than parrying, but it seems very strange for the difference to grow without bound with the speed of the attack. A constant difference seems like it would be more reasonable. Also is blocking with a shield really that much harder than dodging?

Your question actually inverts the causality here. The origin of the relationship for Skill, Parry/Block, and Dodge is based on how penalties to DX are reflected:

Skill - penalty to DX is 1:1 with skill
Block/Parry - penalty to DX is 1:2 with skill, because Parry/Block are half skill
Dodge - penalty is 1:4 with DX, because Speed = (DX+HT)/4, and Dodge is based on Move which is based on Speed.

That said, plenty of things are "penalizes all defenses." If you want to unify them all, use the penalties for Parry/Block for Dodge.

But that's why the penalty for Dodge is low - it's 1/4 of the skill penalty.

[DouglasCole]

Originally Posted by Ulzgoroth

...It probably shouldn't be. If the difference between c and 100*c makes any even slightly meaningful distance aside from turning Relativity inside out, you're shooting from astronomical ranges.


(I have long thought that active defenses, especially Dodge, really need to be modified by travel time at longer ranges. I mean, whatever you think about dodging bullets at close range, it's obviously not hard for unpredictable movement to force a miss if your opponent has to predict where you're going to be two seconds in advance.)

We didn't modify active defenses (though that's clearly one way to do it), but in Tactical Shooting, the Time of Flight rule modifies skill at the time of the shot.

Any rule that works for shooter and defender given the turn granularity of GURPS is going to be tricky. Anything that ignores shooter skill will provoke (justified, I think) howls of "my character with super-high Guns skill can predict where the target is going!" It will also encourage somewhat metagame behavior that any course changes or random movement will completely fox a shooter's ability to hit anything. Of course, at long ranges, this is probably exactly true.

Putting it all onto the attacker, as with the Time of Flight rule, will feel a bit funny because, of course, it ignores the defender's motion which likely will occur before the bullet arrives.

[Ulzgoroth]

Originally Posted by DouglasCole

We didn't modify active defenses (though that's clearly one way to do it), but in Tactical Shooting, the Time of Flight rule modifies skill at the time of the shot.

Any rule that works for shooter and defender given the turn granularity of GURPS is going to be tricky. Anything that ignores shooter skill will provoke (justified, I think) howls of "my character with super-high Guns skill can predict where the target is going!" It will also encourage somewhat metagame behavior that any course changes or random movement will completely fox a shooter's ability to hit anything. Of course, at long ranges, this is probably exactly true.

Putting it all onto the attacker, as with the Time of Flight rule, will feel a bit funny because, of course, it ignores the defender's motion which likely will occur before the bullet arrives.

Yeah, I'm specifically saying that a character could have a guns skill of "Yes, all of it" and it wouldn't really let them do anything about the consequence of long flight times meaning sometimes the target just isn't there, and I want the rules to acknowledge that.

[DouglasCole]

Originally Posted by HANS

The problem with this, again, is that Dodge for firearms does NOT involve dodging the bullet. The speed of the projectile (or laser beam) is completely irrelevant. You dodge the line of sight of the shooter, really. You dodge his presentation (his aim). You move erratically. Again, all the discussions about the velocity of the bullet miss the point. The reason is that we KNOW that you cannot dodge a bullet by seeing the projectile and moving out of its way. However, we also KNOW that you can dodge the presentation and that you can make hitting yourself more difficult. That is Dodge. I concede that the terminology might be flawed, as it lumps it together with dodging things that you can, actually, evade this way (baseballs, spears, 40-mil grenades, etc), but it works.

Cheers

HANS

Shooting at 600yds with an M1 Garand, looking through a spotting scope you could see the bullet travel by the air it displaces. If that were visible to the naked eye, you could likely dodge the bullet the same way (but more difficult) you could dodge an arrow.

The Dodge This rules include two things: a very difficult roll to spot the incoming projectile (penalized by -13 or more because tiny, tiny bullet) and a less-difficult roll to get out of its way assuming you can spot it.

You can easily see and spot slow-moving projectiles like axes and baseballs. You can see and avoid faster and smaller projectiles like arrows. I've seen video of a swordsman cutting an airsoft pellet in two, and you can dodge paintballs. At some point, this ability to see and avoid breaks down, and Dodge This lets that ability break down by applying larger and larger penalties to the perception and avoidance rolls.

It also introduces (or restates; I've seen similar concepts elsewhere) Evasive Movement, which is an attempt to generally make yourself harder to hit.

This article was born from several games with honest-to-goodness suspension of disbelief issues that nearly ruined those games for the players. I hit it from several directions - perception, tactical awareness, evasion, and pure avoidance.

I know - and acknowledged right there in the article - how the Dodge rules work in GURPS, or how they're supposed to work. I also know, from experience as well as repeated complaints here on these forums, where they break down. Dodge This addresses many, though perhaps not all (such as Kalzazz's observation about prediction shots and shotguns) of those complaints systematically, which allows GMs and players to customize their game to taste.

[DouglasCole]

Originally Posted by Ulzgoroth

Yeah, I'm specifically saying that a character could have a guns skill of "Yes, all of it" and it wouldn't really let them do anything about the consequence of long flight times meaning sometimes the target just isn't there, and I want the rules to acknowledge that.

Reducing the benefit of Prediction Shot by 1d per second or thereabouts (and allowing that to give a bonus to dodge) might do it. Would require the target to have actually moved, though.

[Varyon]

Originally Posted by Andreas

I questioned why the difference in difficulty should increase with speed like that.

I see, I misunderstood your question. Basically, you want to know why the difference is based on a multiplier/divisor rather than a simple linear adjustment. I think my example gives a good reason why a linear adjustment is a bad idea - if Dodge is always at +6 relative to Parry, then at the low-speed end (where you'd actually expect to see most characters being able to pull this off) Dodge and Parry are going to be too different. For example, a thrown hatchet is at -1 to Block/Parry, +0 or so to Dodge, which is consistent with Basic Set rules. If we go with the linear adjustment, we can either maintain the old Block/Parry rules or the old Dodge rules. In the former case, Dodge gets a whopping +5 to Dodge a hatchet. In the latter case, Blocking/Parrying a hatchet is at -6. We could go for the worst of both worlds and split the difference, for +3 to Dodge and -3 to Block/Parry.

Originally Posted by Andreas

Those rules give the same penalty for parrying an attack moving at 100,000 y/s as for dodging an attack that moves at the speed of light. That does not seem very reasonable.

Well, to be fair, Parrying an attack moving at 57 mps doesn't really seem all that reasonable, and neither does Dodging an attack moving at lightspeed. Honestly, the speeds you have to be dealing with for the rules to become truly problematic are ridiculous themselves, so things breaking a bit there typically isn't going to be a big deal.

Originally Posted by Ulzgoroth

If, somehow, you character knows where a projectile is going to hit more than a second (really even, say, half a second) in advance their successful basic dodge by not being there shouldn't even take a roll. If they're capable of re-positioning out of the path, they can do so.

But there's no need to have any idea where a projectile is going to hit. The point is moving such that the shooter can only guess at where you're going to be a couple seconds after they pull the trigger.

The shooter may well be able to predict where you're likely to move to, and have the bullet heading there. Unlikely, of course, but then he is up against a 1d-5* penalty per second of flight. Theoretically, under the suggested system, if you have a small enough margin of error in your estimation you can always make certain you aren't in the area when the bullet hits, which would indeed be an automatic dodge.

*If you have a d10, you can actually break the TS penalty down into fractional seconds. At 0.3 seconds, the penalty would be 1d2-2, at 0.5 it's 1d3-3, and at 0.7 it's 1d5-4. 1d2 can simply be 1d6 divided by 3 (round up), 1d3 is 1d6 divided by 2 (round up), but 1d5 needs a 1d10 divided by 2 (round up). If you don't have a d10, 1d5-4 can be approximated as 1d2+1d3-5.

Originally Posted by DouglasCole

Skill - penalty to DX is 1:1 with skill
Block/Parry - penalty to DX is 1:2 with skill, because Parry/Block are half skill
Dodge - penalty is 1:4 with DX, because Speed = (DX+HT)/4, and Dodge is based on Move which is based on Speed.

Ah, and now I see how you came to your numbers. Interesting.

[Ulzgoroth]

Originally Posted by DouglasCole

Reducing the benefit of Prediction Shot by 1d per second or thereabouts (and allowing that to give a bonus to dodge) might do it.

Is there a reason I'm missing for you to state that as a reduction to Prediction Shot that can become a bonus to dodge rather than simply as a bonus to dodge?

Originally Posted by DouglasCole

Would require the target to have actually moved, though.

Yeah, this is emphatically a defensive benefit under 'only if you're actually moving unpredictably'.

Though it shouldn't necessarily require the target to be able to dodge in the normal sense at the moment they're being attacked...though that's getting into the (deliberately avoided) issue of bullet travel really meaning the shot doesn't resolve at the same time as it's fired.

[DouglasCole]

Originally Posted by Ulzgoroth

Is there a reason I'm missing for you to state that as a reduction to Prediction Shot that can become a bonus to dodge rather than simply as a bonus to dodge?

No, I started with Prediction shot and then realized that this should work with shots that aren't prediction shots as well, and didn't reverse-edit.

Though it shouldn't necessarily require the target to be able to dodge in the normal sense at the moment they're being attacked...though that's getting into the (deliberately avoided) issue of bullet travel really meaning the shot doesn't resolve at the same time as it's fired.

This could be hand-waved (and I swear I wrote this already) as shots that are past X range are, in fact, resolved the following turn - or at least defenses are. It might be complicated, but precedents exist. Suppression fire, for example, is resolved any time someone crossed the beaten path of the shots.

[Ulzgoroth]

Originally Posted by DouglasCole

This could be hand-waved (and I swear I wrote this already) as shots that are past X range are, in fact, resolved the following turn - or at least defenses are. It might be complicated, but precedents exist. Suppression fire, for example, is resolved any time someone crossed the beaten path of the shots.

Yeah, it's not hard (if you're already calculating flight time in seconds) to postpone resolution. I'm sure it's been discussed.