A damage system for LogST

[dataweaver]

The following idea is based on a half-remembered recollection of someone's blog post somewhere, over a decade ago. I do not take credit for the idea; but I don't know who to attribute the credit to.

OK; here's the idea:

1. HPs go away. Or rather, the system works as if everyone has 10 HPs. When damage drops you to zero, the same thing happens as per the normal rules. If you reach -10 HPs, the same thing happens as if you reached -1×HP in the current system. -20 is the same as -2×HP; and so on. Basically, your Hit Points cease to be a largely abstract measure that incorporated both how hurt you are and how hard it is to hurt you, and simply become a measure of how hurt you are.

2. HPs are replaced by, for lack of a better term, a “Ruggedness” trait, which has its value set the same way that HP are set in the current system: that is, Ruggedness is equal to ST by default, and can be bought up at the same cost as per buying additional HPs in the current system. Ruggedness scales with mass the same way that ST does; that is, Log ST means Log Ruggedness. Where HPs have been repurposed strictly as “how hurt are you?”, Ruggedness becomes the measure of “how hard is it to hurt you?”

3. Weapon stats and character traits don't measure damage in damage dice anymore; they measure damage as “attack ST”.

4. The damage dice that you roll after successfully hitting a target is determined by the difference between your attack ST and the target's Ruggedness. A difference if 0 rolls the same damage dice as for someone with ST 10 under the current system; a positive difference adjusts the damage upward from there, and a negative difference similarly adjusts it down. That is, you don't roll a huge pile of attack dice unless your Attack ST is overwhelmingly higher than the target's Ruggedness; and if you're rolling a single die with a large penalty, it's not because you're weak in any sort of absolute sense; it's because your target's Ruggedness is significantly higher than your Attack ST. In fact, it's possible for the target's Ruggedness to be so much larger than your Attack ST that you have no hope of inflicting any damage.

This is the heart of the system: the idea that damage done is based on a relative measure, not an absolute one.

That's the essentials of the system. From here, additional work involves determining what the Attack ST of various Innate Attacks, spells, and weapons is; how such things as Damage Resistance and Injury Tolerance interact with this system; how muscle-powered weapons interact with this system; how swarms factor in; and so on. Some thoughts:

1. Under the current system, the biggest difference between HP and Ablative DR is that the former implicitly adjusts the “damage thresholds” (that is, how much damage it takes to go from full health to 0, from there to -1×HP, -2×HP, etc.). With the “damage thresholds” becoming fixed values, what distinguishes Ruggedness from DR in this system?

2. I'm thinking that there might be a parallel between how DR interacts with Ruggedness and how muscle-powered weapons interact with Striking ST. As with the previous thought, I'm not sure what the implementation of this should be.

3. Should Innate Attacks inflict swing damage, thrust damage, or something else with their Attack ST?

Thoughts?

[Anthony]

The big problem I've always run into is that logarithms make multiplication and division easy, but make addition and subtraction hard. Thus, if you want to know what happens when attack goes through a barrier (or armor) and affects what's on the other side, you tend to wind up with one of:

• Layered minor armor winds up ridiculously potent. For example, let's say LogDR is equal to 10 * log10(DR), or actual DR, whichever is less. Let's say a reinforced door has DR 10, and the person behind it is wearing a bulletproof vest with DR 12 (LogDR 11). If you add them together, you get LogDR 21, which is the same protection as a single DR 120 layer. 10+12 = 120 seems wrong.
• Layering doesn't do anything at all (you just use the highest armor value). This would mean 10+12 = 12.
• Dealing with barriers results in table lookup. This means LogDR10 and LogDR11 would add up to LogDR 13.

All of these are inconvenient in their own way.

[Infornific]

Is this what you were remembering? That's only about a year old so you might be remembering something else.

[dataweaver]

I'm definitely remembering something else. That said, I definitely prefer “Body” to “Ruggedness” as a name for the trait that replaces HPs in the Relative Damage system.

[dataweaver]

Originally Posted by Anthony

The big problem I've always run into is that logarithms make multiplication and division easy, but make addition and subtraction hard. Thus, if you want to know what happens when attack goes through a barrier (or armor) and affects what's on the other side, you tend to wind up with one of:

• Layered minor armor winds up ridiculously potent. For example, let's say LogDR is equal to 10 * log10(DR), or actual DR, whichever is less. Let's say a reinforced door has DR 10, and the person behind it is wearing a bulletproof vest with DR 12 (LogDR 11). If you add them together, you get LogDR 21, which is the same protection as a single DR 120 layer. 10+12 = 120 seems wrong.
• Layering doesn't do anything at all (you just use the highest armor value). This would mean 10+12 = 12.
• Dealing with barriers results in table lookup. This means LogDR10 and LogDR11 would add up to LogDR 13.

All of these are inconvenient in their own way.

Agreed — although the table lookup can be made fairly simple: start with the highest-rated layer, then do a table lookup based on how far behind that layer the next one is, and augment the highest rating based on that. For instance, if it's a decibel scale, the toughest layer should get a +1 boost if the next layer is within 6 steps of it, a +2 boost if it's within 2 steps, and a +3 boost if they're tied.

[Infornific]

Originally Posted by dataweaver

Agreed — although the table lookup can be made fairly simple: start with the highest-rated layer, then do a table lookup based on how far behind that layer the next one is, and augment the highest rating based on that. For instance, if it's a decibel scale, the toughest layer should get a +1 boost if the next layer is within 6 steps of it, a +2 boost if it's within 2 steps, and a +3 boost if they're tied.

That's basically what I did. And remember if you're looking at a difference of 6 or more the weaker layer of defensive doesn't significantly improve the stronger layer.

[Seneschal]

The Log thing makes my head spin, but the relative damage is something I introduced into a homebrew system I made, and it worked pretty well! Everything, living or otherwise, has a Body stat that represented the overall size, mass, and structural integrity. Every level corresponds to a doubling of GURPS Basic Lift. Humans are around Body 4 (10 kg), while a blue whale is Body 11 (2,000 kg).

I use a wound system in which also doubles with every step:
- 1 damage is a minor wound (equivalent to 1 GURPS HP of injury)
- 2 damage is a moderate wound (2 HP of injury)
- 3 damage is a major wound (5 HP of injury)
- 4 damage is a critical wound (10 HP of injury), etc.
Everyone and everything has the same number of wounds. You can take several wounds of the same level before any further wounds overflow into the next level, so it's semi-cumulative, but still goes by GURPS's "one good hit is enough to drop you"-philosophy.

Damage is determined by the difference in Body between the attacker. So a blue whale (Body 11) belly-flopping on a human (Body 4) would do 7 damage (the equivalent of 100 HP). Splat.

As one may infer, my group really likes GURPS, but doesn't like playing GURPS, so I made us a simplified system with tiny numbers and simple math that no make brainbox hurtsy.

[zedlopez]

Were you maybe thinking of Anthony's Exponential ST (though your proposal has more in common with the more recent Know Your Own Damage)?

https://sites.google.com/site/anthon...exponential-st
https://sites.google.com/site/anthon...our-own-damage

or maybe tbone's Toughness?

http://www.gamesdiner.com/gurps-toughness
http://www.gamesdiner.com/gurps-new-damage-for-st

[dataweaver]

No, and no. You're not thinking old enough: what I recall was from back in the late 90s/early 00s, well before the Fourth Edition had even been announced.

[Anthony]

Originally Posted by zedlopez

Were you maybe thinking of Anthony's Exponential ST (though your proposal has more in common with the more recent Know Your Own Damage)?

Which is super incomplete, so surprised anyone even knew it exists.