Heavily modified (logarithmic) damage system for GURPS: feedback wanted!

[Varyon]

Originally Posted by ericthered

Ahah! that's it! I wonder if using AV -Infinity wouldn't make more sense.

I mean, 1d-5 is pretty pointless already. Having human skin at AV 0 isn't terrible. Setting it to -1 might work well.

Since we're already using tables and bumping things numbers up from the Size and Range table, I'm curious if a different bump number isn't desirable.

I think I agree that having 1d-5 be largely incapable of causing Injury to a human is probably fine. An average of 0.17 damage and an average of 0 damage aren't that far removed.

I think his current ranges work well (after adjusting TR to be 10 at HP 10, which makes damage work better as well). Consider:

1d-5 is about as low as you can get in damage in GURPS. Having it be DV 1 is intuitive.

This results in human skin being around AV 0, for the baseline. Humans as baseline is intuitive, and rather baked-in to how GURPS normally functions.

Average TR is 10. Given TR is a statistic for the character, this works intuitively for those used to GURPS - above 10 means above-average resilience, below 10 means below-average resilience.

[Infornific]

I took a stab at a creating a damage system tied to log ST a while back. It's here if you want to look at in for ideas.

The effort to work in armor is interesting but I think it might be simpler to come up with some way of combing Armor Value and Toughness for a single value. I tried to do that in my system but I'd probably change how I handle cutting and impaling damage.

I think it might read better if you started by laying out your system and after that how to convert GURPS values to SOLIDS. But that might just be me.

[Varyon]

Originally Posted by Infornific

The effort to work in armor is interesting but I think it might be simpler to come up with some way of combing Armor Value and Toughness for a single value. I tried to do that in my system but I'd probably change how I handle cutting and impaling damage.

You'd need to use the rules for layering armor here, essentially treating TR as though it were another layer. Note this means a TR 10 average human would need AV 7+ armor - equivalent to DR 4-5 - before there would be any benefit to wearing it (of course, I think I've seen mention in the past that historical armors tended to give DR 4+). You lose more resolution, but gain more simplicity... although you'd probably need to shift DV or AV+TR (either +4 to DV or -4 to AV and TR), as there's no longer the armor adjustment.

[Infornific]

Originally Posted by Varyon

You'd need to use the rules for layering armor here, essentially treating TR as though it were another layer. Note this means a TR 10 average human would need AV 7+ armor - equivalent to DR 4-5 - before there would be any benefit to wearing it (of course, I think I've seen mention in the past that historical armors tended to give DR 4+). You lose more resolution, but gain more simplicity... although you'd probably need to shift DV or AV+TR (either +4 to DV or -4 to AV and TR), as there's no longer the armor adjustment.

Mine was a little more complicated. Basically, you combined AV & TR as follows:

If AV>TR, effective Toughness is the higher of

1. 3+AV-((AV-TR)/2)
2. AV

If TR>AV, effective Toughness is the higher of

1. 3+TR-((TR-AV)/2)
2. TR

So if TR is 6 or more higher than AV, the armor is ineffective. My conversion for DR was slower - I assumed DR is quadratic (i.e., 2 DR is four times. So my armor value would be something like:

(log(GURPS DR)*12)+7.

So mail with DR 4 would have an armor value of 14. A character with TR 10 wearing that armor would have a net Toughness of 3+14-((14-10)/2) or 15. Leather Armor would have a value of 11 or so - still providing a little benefit to someone with Toughness 15 or less.

[Varyon]

Musing on this some more, how much thought have you put into how muscle-powered weapons behave? In theory you could keep a note of how much ST-based damage your character "should" do, and toss in the Adds from the weapon to recalculate DV. But that's going to slow things down if a character has to pick up a new weapon during combat, and you also get similar breakpoints as what "round up" would give you between the M16A2 and the AK47, where using a slightly higher-damage weapon functionally boosts damage by x1.5.

I wonder if you could use something more akin to the way layering armor works. That is, instead of a weapon doing thr+2 imp, it's instead something like DV 6. If you have DV 3-5* (from ST), this makes your damage with the weapon be DV 7. If you have DV 6, it's DV 8. If you have DV 7-9, the weapon gives you +1 to DV. If you have DV 10+, you may need to check your strength to use it (much like how current weapons are limited to damage based on 3*MinST), restricting it to DV 10. For cut/imp Weapons of Quality, perhaps Fine gives +1 AM (so better at getting through armor, but no better at wounding unarmored foes), while Very Fine gives the better of +1 AM and +1 DV (so it performs better against unarmored foes... and against those with hardened armor). Might be worth playing around with. Of course, this makes Striking ST intermediate between two DV's useless - but honestly, I think with a system like this, you'd be best served breaking ST up into TR (which would start at 10 and arguably be [+25]/level, although having it ramp up to this - [10], [10], [20], [25], to mimic HP's pricing at lower levels - might be appropriate), BL (following Lifting ST's pricing - or KYOS), and DV (which would start at 5; I'm not sure exactly what would be fair pricing, here).

*The need to match MinST - or MinDV if taking my later advice - may mean you can only have DV 1 or 2 points below that of a typical weapon.

EDIT: Looking at the document again, I see you did have some information on muscle-powered weapons, but it was such that you simply get a flat boost to DV based on the weapon's Adds, which seems excessive. I think revamping the table, with weapons having their own DV that "stacks" with your personal DV as above, would work better. Weapons that are rescaled for a character's ST/DV would actually be fairly simple - every +1 to weapon DV increases MinDV (probably weapon DV -2 for most weapons) and MaxDV (weapon DV +3 for most weapons) by +1, and increases weight by +1 SSR. Generally revamping tables is probably appropriate for this system, along with lumping a lot of similar weapons together, with the exact weapon being more flavor than stats - you don't have M16A2 vs AK47, you just have an Assault Rifle; you don't have Longsword vs Katana, you just have a Hand-and-a-Half Sword. And so forth.

[Sam Baughn]

I put a fair bit of thought into melee weapons and tried a lot of different ways to calculate damage, then settled on the simplest option. It looks like I should have put more thought into it though, because the 'layering' method you propose is brilliant and should work a lot better.

I'm considering dropping Armour Modifiers and just increasing Damage Value and dropping Injury Modifier by the same amount instead. I maybe need to consider it when I'm less tired, but as far as I can see, there's basically no difference between (AM -2) and (DV+2, IM-2). Not sure it actually makes things simpler though; removing one stat seems like a step in the right direction, but it means adding another step in calculating Injury Modifier.

[Varyon]

Originally Posted by Sam Baughn

I put a fair bit of thought into melee weapons and tried a lot of different ways to calculate damage, then settled on the simplest option. It looks like I should have put more thought into it though, because the 'layering' method you propose is brilliant and should work a lot better.

Don't give me too much credit, here - it's just your armor layering rules, applied to damage. I suspect the way to calculate what a given weapon's DV is would probably be to calculate the RAW damage for it using ST equal to MinST, and applying the weapon's Adds to that, but it's something you'll want to play with a bit.

Originally Posted by Sam Baughn

I'm considering dropping Armour Modifiers and just increasing Damage Value and dropping Injury Modifier by the same amount instead. I maybe need to consider it when I'm less tired, but as far as I can see, there's basically no difference between (AM -2) and (DV+2, IM-2). Not sure it actually makes things simpler though; removing one stat seems like a step in the right direction, but it means adding another step in calculating Injury Modifier.

Armor Divisors struck me as a great idea when I first saw them in GURPS, and I think getting rid of them would cause more issues than it would solve. Really, I think "Apply this modifier to AV before comparing it to DV" is sufficiently simple. It's one number (the modifier) and one operation (apply modifier), rather than one number (again, the modifier) and two operations (apply the modifier to DV, then apply the opposite of the modifier to IM)... or two numbers (one for DV, one for IM, with each being the opposite of the other) and two operations (applying each to DV and IM).
EDIT: Consider if, instead of an Armor Divisor, GURPS had opted to multiply damage, then divide wounding by the same factor (IIRC, this is how they handled armor piercing and hollowpoint bullets in Fallout: New Vegas, to get around inherent shortcomings of the Fallout 3 engine it was built on top of; of course, it works there because it's a computer handling everything, but some sort of armor divisor/multiplier would have called for less computation and been overall cleaner). The latter is clearly more complicated - and more prone to accidental errors of calculation - than the former.

[Anthony]

Originally Posted by Varyon

Armor Divisors struck me as a great idea when I first saw them in GURPS, and I think getting rid of them would cause more issues than it would solve.

There's no particular reason why 2d pi- and 1d(2) pi (both of which average 3.5 injury and will penetrate DR 7) should have different mechanics. Getting rid of either armor divisors or wounding modifiers seems like it would be a net improvement.

[Varyon]

Originally Posted by Anthony

There's no particular reason why 2d pi- and 1d(2) pi (both of which average 3.5 injury and will penetrate DR 7) should have different mechanics. Getting rid of either armor divisors or wounding modifiers seems like it would be a net improvement.

If Hardened armor doesn't exist, perhaps. Are you suggesting something with, say, DR 20 and one level of Hardened should instead simply be DR 40? Note also that those two behave differently on hits to the Skull/Eye and Vitals, although that's arguably a bug of sorts in the GURPS rules.
EDIT: I'll also note that, if you're tracking it at least, the 2d pi- should cause less physical damage to any cover being shot through (same depth of hole - all the way through - but less width to it). Realistically, there really is a difference between a fast, small standard bullet and a slower, larger armor-piercing one.

[Anthony]

Originally Posted by Varyon

If Hardened armor doesn't exist, perhaps. Are you suggesting something with, say, DR 20 and one level of Hardened should instead simply be DR 40?

Or DR +20 vs a specific class of attack. Hardened armor doesn't actually represent anything meaningful.

Originally Posted by Varyon

EDIT: I'll also note that, if you're tracking it at least, the 2d pi- should cause less physical damage to any cover being shot through.

No it shouldn't. The effort required to penetrate armor is more or less linear in quantity of armor affected, so the way you improve armor penetration is by making a narrower, deeper hole (for that matter, armor divisors on cutting attacks don't make any sense at all, things that make blades chop through armor better also make them chop through flesh better).