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Old 07-18-2013, 05:24 PM   #21
lexington
 
Join Date: Jan 2010
Default Re: IT:DR (Armored Flesh)

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Originally Posted by gjc8 View Post
But what does "not threaten the structural integrity of the object" mean in the context of, eg, explosions? Or, really, anything but piercing/impaling.
A shallow dent.

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Originally Posted by gjc8 View Post
Actually, I'm pretty sure that attacking anything but a lump of flesh (and probably a more-or-less human-dimensioned lump of flesh) is outside the design case. The frigate and the muskets come to mind.
That's a result of blowthrough being based on HP rather than thickness, IMO. A frigate is mostly air, after all, cannon balls should hardly being getting full injury when they hit.

But yes, whatever the reason once you move away from "humanoid things between 6HP and 20HP" results begin to noticeably breakdown.
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Old 07-19-2013, 06:29 AM   #22
reddir
 
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Default Re: IT:DR (Armored Flesh)

I'm sorry to butt in here, but this raises a cool idea I'd like to have more information about.

Is there such a thing as a 'damage divisor' type of armor or damage resistance or force screen in GURPS?

If not, what would be a fair price for that?
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Old 07-19-2013, 07:09 AM   #23
Varyon
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by Otaku View Post
Damage Resistance reduces the damage done to a target... that is all that is safe to assume. Generic and Universal, remember? Sometimes it is a literal shell, other times a force field around the subject... but it could also be something unidirectional. Its questionable usage at higher TLs is irrelevant to the discussion... and I am longwinded enough as is without giving me extra material. ;-)
I'm well aware that DR is meant to be able to represent anything from a shell to a being composed of hard-to-penetrate material. The issue I'm seeing is that DR behaves only as an outer shell. IT:DR seems to behave more like the hard-to-penetrate bit than DR does.

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Originally Posted by lexington View Post
That's a result of blowthrough being based on HP rather than thickness, IMO. A frigate is mostly air, after all, cannon balls should hardly being getting full injury when they hit.
Actually, the musket problem is a combination of ships having too low of DR (fixable), GURPS damage being completely cumulative (fixable), and the abstraction of counting the HP of an entire ship when only a small, relatively-unimportant part of it is being attacked (technically fixable, but potentially ungameable). Blowthrough certainly isn't the issue here, because a musket ball isn't likely to go all the way through a ship in the first place.

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Originally Posted by lexington View Post
But yes, whatever the reason once you move away from "humanoid things between 6HP and 20HP" results begin to noticeably breakdown.
Agreed. Personally, however, I think it's worthwhile to try to find ways to fill in these gaps. I think IT:DR (AF) does a decent job at the particular issue I'm having.

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Originally Posted by reddir View Post
Is there such a thing as a 'damage divisor' type of armor or damage resistance or force screen in GURPS?
Injury Tolerance: Damage Reduction divides penetrating damage by a factor depending on its level. A character with DR 4 and IT:DR 2 hit by a 20 damage attack would take (20-4)/2=8 points of damage, which would then be converted to injury based on the weapon's wounding modifier. You can find the Advantage in Powers.

...


I think I'm missing a piece of data here that would be useful for determining if this trait is realistic (for objects/machines, of course, not so much for people). All those RHA penetration tests that you hear about for firearms (and that apparently a good deal of the GURPS stats of firearms are derived from)... are those cases where you have a big lump of RHA steel that you shoot at and then see how deep the bullet went, or are those cases where you have a set of plates of various thickness that you shoot at and determine the thickest plate the weapon system can penetrate?
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Old 07-19-2013, 07:39 AM   #24
lexington
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by Varyon View Post
Actually, the musket problem is a combination of ships having too low of DR (fixable), GURPS damage being completely cumulative (fixable), and the abstraction of counting the HP of an entire ship when only a small, relatively-unimportant part of it is being attacked (technically fixable, but potentially ungameable). Blowthrough certainly isn't the issue here, because a musket ball isn't likely to go all the way through a ship in the first place.
Sorry, yes, for muskets blowthrough isn't an issue. Cannon battles also don't work properly. A hole in the hull should hardly count for dozens of points of damage.

Armor is also extremely low for wooden ships, I agree. It sounds like in reality they had very thick hulls.

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Originally Posted by Varyon View Post
Agreed. Personally, however, I think it's worthwhile to try to find ways to fill in these gaps. I think IT:DR (AF) does a decent job at the particular issue I'm having.
I think it does, yes, I'm partly being difficult because that's the best way to see if things actually work (and partly because I do think the DR system is better).

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Originally Posted by Varyon View Post
I think I'm missing a piece of data here that would be useful for determining if this trait is realistic (for objects/machines, of course, not so much for people). All those RHA penetration tests that you hear about for firearms (and that apparently a good deal of the GURPS stats of firearms are derived from)... are those cases where you have a big lump of RHA steel that you shoot at and then see how deep the bullet went, or are those cases where you have a set of plates of various thickness that you shoot at and determine the thickest plate the weapon system can penetrate?
They're testing armor (hence Rolled Homogeneous Armor) and fire against a plate of the material. Guns are inevitably rated for "penetration". I can't find any specific examples online but you can find videos of people doing these tests on their own (with a steel plate or whatever) and they end up with dents or with holes, never with a bullet embedded in the armor they're testing.
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Old 07-19-2013, 07:59 AM   #25
Rupert
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by lexington View Post
They're testing armor (hence Rolled Homogeneous Armor) and fire against a plate of the material. Guns are inevitably rated for "penetration". I can't find any specific examples online but you can find videos of people doing these tests on their own (with a steel plate or whatever) and they end up with dents or with holes, never with a bullet embedded in the armor they're testing.
Actually, with thick sheets of armour, as found on tanks and warships up to the end of WWII, you did get projectiles stuck in them. This would sometimes happen when the projectile almost, but not quite had the energy to penetrate.

In fact, if the nose had penetrated some militaries counted it as a penetration for testing purposes, while some did not, and others required the projectile penetrate in a condition where it could still explode if explosive, or in one piece, while others just required that it made a hole - it was (and still is, sometimes) a real mess.
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Old 07-19-2013, 09:52 AM   #26
Varyon
 
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Default Re: IT:DR (Armored Flesh)

I managed to find a bit more information on penetration tests, namely these two studies. Both made use of thick plates of armor - too thick for the penetrators used to punch through. Neither made any note of needing to find plates that were "just right," as would be necessary if partial penetration only occurs over a very short range of penetrator vs armor. The general tone and methodology of each study indicates that my initial assumption (penetration is based on how deep the projectile goes rather than how thick of a plate it can punch through) was correct. In particular, the linear relationship seen between armor hardness and depth of penetration in the first study indicates IT:DR (AF) may indeed be realistic... at least for homogenous chunks of RHA steel.
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Old 07-19-2013, 10:07 AM   #27
naloth
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by Otaku View Post
Yes... but you said it yourself: usually. GURPS injury/damage rules are built first and foremost for people. Sometimes armored people, but people.
GURPS has strong roots in human centric statistics but it's quite good at handling other characters and situations.

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<snip extraneous abstraction info>

Damage Resistance reduces the damage done to a target... that is all that is safe to assume. Generic and Universal, remember? Sometimes it is a literal shell, other times a force field around the subject... but it could also be something unidirectional. Its questionable usage at higher TLs is irrelevant to the discussion... and I am longwinded enough as is without giving me extra material. ;-)
Yes, and not really relevant. The game effect is that damage under DR doesn't do any harm and damage over DR is injury.

The higher TL thing isn't really important either - it's just an example where you often have DR values that are a magnitude greater than the HP they protect. Overcoming such DR by a little bit (relative to the DR) usually wipes out the very tiny HP value entirely in one shot. Ideally you want to have them in proportion somehow so that attacks are meaningful but not instant kills.

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I am not familiar with the "Super ST" rules... but if we are trying to accurately reflect reality, that doesn't matter, does it? Reality isn't always point optimized, and if something realistic isn't cost effective, it means the cost assessed is wrong and not the mechanics to which that point cost is assessed.
That two entirely different discussions. Different ways to buy things are just different tools inside the system. Being point efficient is important but only when you're building PCs and balancing them against each other. Some game mechanics (and abilities) are realistic, some aren't. Super ST and IT:DR are just different ways to scale up abilities. Some campaigns function better with that method of scaling while others don't. Sometimes it's because technology renders abilities less useful and other times because abilities don't scale well with character values. Striking ST generally isn't worth it where Innate Attack is available. Buying a few points of DR is a luxury when you can put in Kevlar instead.

IT:DR is simply a different method of making something tougher and it models some classic abilities much better. It's an easy way to tack on "takes half damage vs X" instead of trying to figure out what quantity of additional HP/DR to take. Likewise, while "massless" HP and ADR can be used for a damage soak, sometimes it's easier to just use a damage divisor.
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Old 07-19-2013, 10:13 AM   #28
lexington
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by Varyon View Post
Neither made any note of needing to find plates that were "just right," as would be necessary if partial penetration only occurs over a very short range of penetrator vs armor.
Why would there be a desire to get the armor "just right" in any case? You hardly want your armor to be obsoleted by the next upgrade in weapons technology.

I'm not clear on what your "narrow range" means, to be honest. It's not like the armor ceases to be useful once it can be penetrated. A weapon still has to be dangerous when it comes out the other side. Armor that makes an attack far less effective is still good armor.


Another point of complexity: In small arms body armor the NIJ standard is not "zero chance of penetration" but "fifty percent chance of penetration".

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Originally Posted by Varyon View Post
The general tone and methodology of each study indicates that my initial assumption (penetration is based on how deep the projectile goes rather than how thick of a plate it can punch through) was correct.
Extremely high speed long rod penetrators behave significantly unlike small arms. Newton worked out that penetration can be approximated as Projectile Length (Projectile Density / Target Density), with little consideration to the exact speed or material hardness.
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Old 07-19-2013, 10:52 AM   #29
Varyon
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by lexington View Post
Why would there be a desire to get the armor "just right" in any case? You hardly want your armor to be obsoleted by the next upgrade in weapons technology.
"Just right" because they needed to see how much more/less effective the various armors were. In the first study, they were comparing RHA against a range of "improved" RHA steels, in the second they were trying to figure out if hitting a "notch" in the armor was more effective (compared to hitting flat armor, with the thickness of the flat plate being equal to the thickness of material beneath the notch). If penetration follows the way it would work in GURPS - with a long range of "no damage," a narrow range of "some damage," and then "completely penetrated through," they would need to have the armor in the narrow range of "some damage," as otherwise there isn't going to be a very measurable effect (in the "no damage" range, decreasing penetration isn't going to do anything; in the "punch through" range, you would need to be on the lower end of it for a decrease in penetration to actually result in the projectile not punching through).

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Originally Posted by lexington View Post
Extremely high speed long rod penetrators behave significantly unlike small arms. Newton worked out that penetration can be approximated as Projectile Length (Projectile Density / Target Density), with little consideration to the exact speed or material hardness.
That is unfortunate. Looks like I'll need to look around some more to find out if IT:DR (AF) works for more traditional penetrators, then.
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Old 07-19-2013, 01:47 PM   #30
Otaku
 
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Default Re: IT:DR (Armored Flesh)

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Originally Posted by Varyon View Post
I'm well aware that DR is meant to be able to represent anything from a shell to a being composed of hard-to-penetrate material. The issue I'm seeing is that DR behaves only as an outer shell. IT:DR seems to behave more like the hard-to-penetrate bit than DR does.
The quote you were responded to was directed at another poster who's comment was quoted before that. Your response may be appropriate to other statements I have made, but quoting what you did kind of makes it confusing.

Speaking of which I am going to answer another of naloth's comments.

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Originally Posted by naloth View Post
The game effect is that damage under DR doesn't do any harm and damage over DR is injury.
Depends on the nature of the DR and level of detail of the game... and sometimes that is an appropriate result - if you didn't manage to "break it", it isn't damaged.
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