IT:DR (Armored Flesh)

[Varyon]

Occasionally in fiction, you have a creature/machine who has "flesh" that is significantly more difficult to penetrate than that of a human. To properly damage such a foe, armor-piercing weapons/ammunition (or techniques) are necessary. This goes beyond simply having a tough outer shell - every millimeter of flesh is equally difficult to penetrate.

How do we represent such characters in GURPS? DR may be tempting, but ultimately falls flat as it seems better to represent initial resistance to damage. It also has the oddity that, once you can reliably crack the DR, switching to AP ammo (with its reduced wounding modifier) results in less damage! The armored flesh seems more like something that would be DR assessed per HP of damage, effectively being a multiplier to HP, so perhaps higher HP is appropriate? Unfortunately, this has the same effect as above, where you are better off using non-AP ammo - in fact, hollow point may well be your best bet.

The ideal method would be to have Injury Tolerance: Damage Reduction that is affected by armor divisors. What would be the best way to build something like this? The simplest method is as a Limitation on IT:DR - call it Armored Flesh or what-have-you, its effect would be that Armor Divisors apply, reducing the value of IT:DR down to a minimum of 1 (the level baseline humans have). What value should such a Limitation have? Of course, in some fiction armor piercing effects are even more effective than this would indicate - often, any Armor Divisor completely negates the target's IT:DR, even if you're just dealing with AD(2) against a creature with IT:DR 100. I'm thinking it would be appropriate to give the character a Weakness (I think that's the Disadvantage - if not, it's the one that's the exact opposite of IT:DR, multiplying rather than dividing damage) against attacks with Armor Divisor... but how should we set the frequency, and how do we account for the fact that this multiplier can only negate IT:DR, not increase damage beyond it?


tl;dr: What is a fair Limitation value on IT:DR that is affected by Armor Divisors, and how do we build a character who has IT:DR that effectively multiplies Armor Divisors against it?

[lexington]

I don't see why DR isn't what you want.

A block of steel has DR that rises faster than HP to represent that "ever millimeter of flesh is equally difficult to penetrate".

[Varyon]

Originally Posted by lexington

I don't see why DR isn't what you want.

A block of steel has DR that rises faster than HP to represent that "ever millimeter of flesh is equally difficult to penetrate".

Because DR subtracts from damage, rather than dividing damage. A block of steel would be a good case of an object that should have IT:DR with Armored Flesh. A 1 yard cube of RHA steel would have 188 HP and offer 2520 DR to anything behind it. But what if we are targeting the block of steel itself? If we apply the 2520 DR, only things that would completely penetrate it are going to damage it at all. Additionally, regardless of what DR we set, once you get past it you end up with any excess damage being applied directly to HP. Let's say we go with DR 1236 (this will have it nearly continue to give DR 2520 to whatever is behind it - 1236 for DR going in, 47 for HP/4, 1236 for DR coming out is a total of 2519). So, it takes (using average rolls) no damage up to 350d, comes close to risking being destroyed at 450d, and isn't completely penetrated until a bit over 700d (at which point it is at -6x HP and is "dead"). These results are more consistent with having an armored shell than with being composed of something tough.

If we instead model this cube of steel with IT:DR (Armored Flesh), it still has 188 HP (still homogenous and the same weight, after all), has no DR (it lacks an armored shell, because it is armor), and has IT:DR (AF) 54. It should probably have Cosmic (round down) if using the default GURPS wounding system (I prefer lwcamp's House Rules here). In this case, that 350d attack drops it to a little over 7/8 HP, and the 700d attack nearly penetrates it, causing a little less than 1/4 HP damage. So, you have a linear progression of damage, and have the possibility of punching through the cube without outright destroying it, as one would expect of "armored flesh" rather than an outer shell of armor.


EDIT: I forgot to mention it in the first post, but IT:DR (Armored Flesh) would also include the Limitation that it is applied before the blowthrough damage cap, and the Enhancement that it also increases the DR the character grants as Cover. So, for the block of steel above, you divide damage by 54, then apply the damage cap of 47. Similarly, the block grants DR equal to 188/4*54=2538 (close enough to 2520). I assume these two (which are probably edge cases) cancel out.

EDIT2: During the last edit I noticed that, with a homogenous object giving cover DR of 1/4 HP, I had the wrong damage divisor. 54 is the correct one. As an added bonus, this value works for any cube of RHA steel, meaning each material could be given an IT:DR (AF) value that would be consistent for modeling it.

[lexington]

Originally Posted by Varyon

Because DR subtracts from damage, rather than dividing damage. A block of steel would be a good case of an object that should have IT:DR with Armored Flesh. A 1 yard cube of RHA steel would have 188 HP and offer 2520 DR to anything behind it. But what if we are targeting the block of steel itself? If we apply the 2520 DR, only things that would completely penetrate it are going to damage it at all. Additionally, regardless of what DR we set, once you get past it you end up with any excess damage being applied directly to HP.

The block of steel would protect people behind it with DR 2567, actually.

When you hit a block of steel with a fist nothing happens to the steel.
When you hit a block of steel with a wrecking ball you dent the steel.

Using DR simulates this. Using IT:DR does not simulate it at all. Nothing I would describe as having "flesh made of armor" could have a person gradually punch through it. If its superdense (like various Marvel superbeings) it would have very high HP, IT:DR is a cheap way to simulate that. I think the game mechanical effects that you want are DR30 plus IT:DR at whatever level you like, I just don't think it matches the justification you're using.

[Tinman]

If you really feel that you need to use IT: Damage Reduction, go ahead and do it. I don't see why you need a new class. As to what the modifier would be: it's very dependant on how available AP is. Ball park, I would say -10%.

[Varyon]

Originally Posted by Tinman

If you really feel that you need to use IT: Damage Reduction, go ahead and do it. I don't see why you need a new class. As to what the modifier would be: it's very dependant on how available AP is. Ball park, I would say -10%.

-10% sounds rather low, as AP is typically available in some form at any TL above 2 (IIRC), and in campaigns where characters can get this form of IT:DR, I'd imagine there would be AP available as part of various Advantages and the like. I was thinking somewhere around -20%, reversing the worth of Hardened on DR, but thought it might even be appropriate to go higher (as under this scheme, IT:DR is by default fully hardened).

Any ideas on how to go about the bit where armor divisors are even more effective against the IT:DR?

[Varyon]

Originally Posted by lexington

The block of steel would protect people behind it with DR 2567, actually.

When you hit a block of steel with a fist nothing happens to the steel.
When you hit a block of steel with a wrecking ball you dent the steel.

Using DR simulates this. Using IT:DR does not simulate it at all. Nothing I would describe as having "flesh made of armor" could have a person gradually punch through it. If its superdense (like various Marvel superbeings) it would have very high HP, IT:DR is a cheap way to simulate that. I think the game mechanical effects that you want are DR30 plus IT:DR at whatever level you like, I just don't think it matches the justification you're using.

Did you happen to read the rest of the post? I continued on to model the block of steel where it would give DR 2520 and then, when I came to modeling it as IT:DR, I mentioned the fact that under default GURPS wounding rules it should realistically get Cosmic (Round Down), to insure you can't slowly punch through the big chunk of steel. With the linked house rules this isn't even necessary, as wounds below 1/16th HP are outright ignored.

[lexington]

Originally Posted by Varyon

Did you happen to read the rest of the post? I continued on to model the block of steel where it would give DR 2520 and then, when I came to modeling it as IT:DR, I mentioned the fact that under default GURPS wounding rules it should realistically get Cosmic (Round Down), to insure you can't slowly punch through the big chunk of steel. With the linked house rules this isn't even necessary, as wounds below 1/16th HP are outright ignored.

You made some significant edits to that post. The post as it existed when I quoted it talked about being able to punch through it given time as a desirable trait . . .

[Mangolaw]

I agree, high DR makes the most sense to me.

In games I've played the only time this sort of thing came up was with creatures like tree ents who's flesh was essentially wood! A combination of DR and injury tolerance seemed to sufficiently describe their toughness.

As far as I can see the rules seem to encourage human sized things with exceptionally high DR to take the ablative limitation so that the DR pretty much just acts as a second skin. I'm not sure if that's useful to you though.

[Sunrunners_Fire]

Originally Posted by Varyon

What is a fair Limitation value on IT:DR that is affected by Armor Divisors,

1 / (1 + 170%) = 37%
... and so either -35% or -40% depending on which way you wish to round it; -37% if you don't wish to.

Originally Posted by Varyon

and how do we build a character who has IT:DR that effectively multiplies Armor Divisors against it?

I believe the above does this, though I may be misunderstanding the question.