Independent Body Parts

Cost: [35]
A form of Injury Tolerance on page 52-53 of GURPS Powers.
==just one limb==
"Zombie Arm" in pyramid 4/1 uses a -40% disadvantage if IBP only applies to a single arm
This is the same value as if you limited DR tat way.
== Torsos ==
Torsos do not have an identifiable "HP required to destroy", though they do have HP of 100% implied by how they operate as Cover DR.
== Limbs ==
IBP can work more effectively by incorporating new hit locations introduced in Low-Tech.original entry by Tycio
The pelvis location does this for limbs. The location is somewhat mis-named though. The pelvis is a big bone connected to BOTH legs, however when reading how injuries to it work, it becomes clear that there are actually TWO pelvis locations: one for each leg:
*Instant Armor page 19 "Until healed, you have Lame (Missing Legs)(p. B141)." This matches B419's description of the effect of a crippled leg. Therefore the "pelvis" is actually the Hip Joint effectively.
It thus makes more sense require damage by applied to the hip to sever the leg from the thigh and below.
This should be required to represent severing a leg, with targetting the thigh itself actually damaging it!
The shoulder is a location mentioned in LT which is analagous to this. That should be assumed as the target (at -3, harder to hit than trying to damage the limb itself) when talking about severing an arm!
The knee would be where you would target to sever HALF the leg, from the shin and below. The ankle presumably is what would sever the foot.
The splitting of legs into thigh/knee/shin is found in Low-Tech for armor sub-locations. It does not use "hip" but this IS effectively what the "pelvis" represents.
*taking into account an elbow location should complicate IBP: it should be possible to have a "hand+forearm" ally which results either from severing the arm at the elbow, or severing it first altogether but then targeting just the upper aftarm and destroying that half of it.
*similarly a knee location should have a "foot plus shin" ally who is better than "just a foot" but inferior to "foot plus shin plus thihg".
Unlike a hand/foot by itself (which can move due to fingers/toes) a "solitary thigh" or "solitary shin" or "solitary forearm" or "solitary aftarm" probably would not be able to move, so severing a "handless arm" at elbow or "footless leg" at knee ought to effectively incapacitate it as an ally.
====blood notes====
"intended for undead" probably assumes that the optional Blood Loss rules would not be in play due to No Blood.
In cases where this does apply, severing a limb causes HUGE blood loss to the torso, and would probably also apply to a loss of HP by the limbs themselves.
This would explain why the head would not live for a particularly long period of time after severing, nor the torso survive long after decapitation.
Treating extremities/limbs/allies as allies with their own HP is an approach that could make sense even without IBP. The difference being that they are obviously not animate allies who can DO anything.
This is like the Reattachment Only version ("they can't fight for you") whose only benefit is the capacity to reattach limbs and damage not crossing over.
The crossing over of damage is somewhat exaggerated anyway, and optional rules were suggested in Basic to limit that. Optional Rules for Injury on B420 called this Last Wounds which appears right after Blood Loss and Cumulative Injury which dictates:
:once you have less than 1/3 your HP left, you can totally ignore any wound to a limb or extremity
Exceptions being:
*critical hits
*crippling hits
*injury equal to 1/3 your HP or more at once
This is still problematic though, because being killed by ANY blow to the foot (not just a 1 HP blow) still stretches belief.
The "crippling hits" exception is also a problem when combined with "Cumulative Injury", since it does allow 1 HP injuries to cripple a foot if prior injury existed.
The need for extremity-injury to cause overall HP loss really isn't needed at all if using Blood Loss because BL gives a mechanic for systemic HP loss from ANY injury. It doesn't necessarily represent blood leaving the body, but also internal bleeding.
The main problem with it is a lack of granularity. HT rolls every minute don't cause immediate compromising in combat. Bleeding for 1 HP or 3 HP is also a BIG impact.
*if using a system with <1 HP fractional granularity (ie 0.1 increments) then this could be tweaked to be "per 10 seconds" or "per second", with failures resulting in smaller losses such as 0.1. Instead of requiring 3 consecutive successes for bleeding to stop, the requirement might be tweaked to 4 or 5 consecutive successes, due to more rolling required
**or perhaps instead of # of successes, be linked to some kind of "cumulative margin" system, where MoS are totalled up and bleeding stops when a target number is reached. This avoids a "bleed forever" problem where someone might win 2/3 rolls but unluckily fail every 3rd roll and never stop.
The "-1 per 5 HP lost" is probably written with 10 HP humans in mind. "Per 50% HP lost" is probably more fair.
MA137 under Veins and Arteries mentions "The sudden blood loss increases the wounding modifier" implying a "spurting effect" of rapid loss preceding a 1 minute countdown and HT roll.
*"ignore crippling effects and damage limits for limbs" means this cannot cause severing but allows for unlimited HP loss, making it incredibly powerful.
The femoral artery is named after the femur, the upper leg bone in the thigh. This eventually branches into the anterior tibial artery (front of shin) and posterior tibial artery (back of shin) below the knee.
The brachial artery is named after the arm/aftarm in general runs along the upper arm bone (humerus) so it could also be thought of as the humeral artery. It splits into radial artery and ulnar artery below the elbow.
The VaA rules could be elaborated upon further than general MA concepts. The usual guideline is an extra -3 for a sublocation, just like Joints uses.
The problem is that -2 for limb needs to be split into -3 for "proximal limb" (thigh or aftarm) and -3 for "distal limb" (shin or forearm). This would mean it would be -6 to target the femoral/brachial arteries mentioned on MA137, that thigh/aftarm armor protects against it, and that they could not be targeted by attacking an exposed shin/forearm since DIFFERENT arteries exist there.
Arguably since the upper is "meatier" you could make the lowers an additional -1, -4 to hit. Since this is the penalty to hit extremities, those could be increased to -5. OR: use the traditional -2 to hit for proximal limbs, and -3 for only the distal limbs, keeping extremities at -4.
Blood loss should exist by targeting arteries in "distal limb" locations, but to a lesser degree. Being harder to hit, they would be targeted at an extra -1 relative to proximal-limb arteries, and penalties should be lesser (clotting should be easier).
MA137 notes "Dismemberment still requires twice the injury needed to cripple the whole body part – not just the joint." for Joints hits: the lower injury thresholds only pertain to crippling.
That's one major problem: joints (whether the hip/shoulder or knee/elbow) are natural severing points for limbs, because it allows dismemberment via cutting merely through muscle+ligament instead of muscle+bone.
Ignoring MA137's note reflects that: just require twice the injury needed to cripple the JOINT (not the whole body part) for severing. This would be 2/3 HP for limbs and 1/2 HP for extremities.
====fighting notes====
*B141 "You have lost some, but not all, of your legs" actually doesn't appear to distinguish a difference between which leg was crippled.
*"You can still kick, but between the standard -2 for a kick and the -6 for this disadvantage, you do so at DX-8!" This gives the impression you can kick with EITHER leg, and it doesn't matter which leg was crippled.
*the -2 could be removed via the Kicking Attack technique
*Martial Arts 99 Lying Face Up "modified attacks" allows ignoring the -2 penalty for kicks in a lying posture, so it would only be DX-6. There appears to be no "stability" benefit for those who bought up Kicking Attack though. The idea being this only buys off a penalty which applies in non-LFU situations
**this does not however take into account the -4 to attacks for a Lying posture, which bumps it up to DX-10.
***this can be bought off via MA73's Ground Fighting technique. "Cannot Exceed Prerequisite Skill" is a soft cap which can be removed via Technique Mastery which eventually makes ground fighting even more impressive than standup fighting in point efficiency.
*there is no known way to buy off this -6 DX penalty as a technique.
Presumably kicking can only be done with the "one leg" someone has (or "non-crippled leg" in the case of someone only suffering temporary crippling). Thus there would ben o way to attack with the non-crippled leg in cases where it's still there.
*although perhaps it might be used via Proxy Fighting or as a Fist Load
PU2p6 Peg-Leg Fighting treats sideslips like retreats, presumably ignoring the -1 they usually have to the usual base. This doesn't alter the -2 penalty for forward-slipping through
*unpredictable all-out attacks giving -1 to defend via exploiting the "lurching gait". Without the perk there is no exploiting of the gait.
== Detachable Head ==
When struck on the neck or head, don’t apply injury to your HP. Instead, apply it to that body part’s HP score! A cutting attack that would cripple a limb or extremity costs you the use of that part (see p. B421)
* In this case "inflicts no injury" does not apply to head blows (face/skull) because cutting attacks to that location do not cause decapitation, that happens when the neck is hit!
* Conversely the neck itself IS injured. It is presumably destroyed by this, because a severed head has Move/Dodge of 0, whereas a neck+head should theoretically be able to wriggle around using neck muscles.contested assertion!
* A severed head under IBP rules has merely HP/2 HP. Apparently less than the neck itself. No separate HP amounts are given for the face or skull.
=== The Seat of Consciousness ===
*If your head is your seat of consciousness, your body fights as its ally.
*If it isn’t (for instance, if you have No Brain), your head fights as an ally of your body!
Creatures like skeletons which have no brain apparently do not have an identifiable "seat of consciousness" in any particular body part. Presumably the "seat of consciousness" for them would be the torso, since that is the only location which has no rules for fighting as a separate ally. Most fantasy skeletons don't have IBP levels of durability, however.
=== Errata and Considerations ===
By the wording of the advantage, IBP makes it effectively impossible to try and destroy the neck with an initial cutting attack, or to sever the ally with a non-cutting attack. Consider that any attack on the head still counts vs the head's HP (base HP/2).Powers, p.52
== As Cybernetics ==
As an alternative to using this to building cybernetic limbs, in 2007 Kromm posted http://forums.sjgames.com/showthread.php?p=376027 proposing that "it's mechanical" is a 0-point injury and gave this breakdown:
:Electrical (Limited, Arm, -40%) [-12]
:High Pain Threshold (Limited, Arm, -40%) [6]
:Immunity to Metabolic Hazards (Limited, Arm, -40%) [18]
:Injury Tolerance (Independent Body Parts; Limited, Arm, -40%; Reattachment Only, -50%)* [7]
:Injury Tolerance (No Blood; Limited, Arm, -40%) [3]
:Injury Tolerance (Unliving; Limited, Arm, -40%) [12]
:Maintenance (1 person, Monthly; Limited, Arm, -40%) [-1]
:No Extra Effort (Limited, Arm, -40%) + No Fatigue (Limited, Arm, -40%)† [0]
:Reprogrammable (Limited, Arm, -40%)‡ [-6]
:Social Stigma (Valuable Property; Limited, Arm, -40%)** [-6]
:Susceptible 1 (Unclean Environments; Limited, Arm, -40%)†† [-1]
:Unhealing (Total; Limited, Arm, -40%) [-18]
:Unnatural Features 5 (+5 to detect with sensors; Limited, Arm, -40%)‡‡ [-3]
:*Simulates independent HP, ability to remove/cripple arm without affecting overall health, etc.
:† The usual zero-point feature of machines that can neither have nor burn FP.
:‡ Represents the manufacturer's ability to hide evil programming, the limb's susceptibility to hacking and machine control, and random programming glitches.
:** Stands for the fact that airport personnel can ask you to remove it, judges might decree that you can't have it in jail, etc. It's "just" property, not a part of you that others need to respect. Even chopping it off in a fight might be vandalism but not assault!
:†† In salt air and other very minor corrosive environments, it needs to make the HT rolls on p. B485, while meat people do not.
:‡‡ Specifically, the limb sets off sensors that detect RF emissions, metal, etc., in a way that live people do not.
:Total: -1 point.
And arguably, that -1 point could be balanced by a 1-point Accessory perk, since in most settings, you can build in a minor gadget for close to no cost.
Clarifies in http://forums.sjgames.com/showpost.php?p=376446&postcount=14 that Unhealing prevents reattachment.
Category:Advantages