How can you inflict % HP damage in GURPS?

[GodBeastX]

Originally Posted by Kromm

One way to look at things:

Unliving objects have twice the HP of living ones. Homogenous ones have twice the HP of Unliving ones. Injury Tolerance (Unliving) is 20 points; Injury Tolerance (Homogenous) is 40 points. So roughly speaking, each doubling of HP corresponds to a 20-point trait. Now of course those traits don't actually affect HP, but we could posit that removing them from an object that has them would temporarily make it flimsier, so we could imagine that's Affliction with Negated Advantage, +20%, but we could call it Hit Point Reduction, +20% instead.

Normally, that would work just once, so if repeated uses stack, that's Cumulative, +400%. And duration is normally minutes, so if it's "permanent until healed," that's Extended Duration, Permanent, +150%.

There would still be resistance rolls aided by DR; to remove the effects of DR, add Cosmic, +300%.

So for 97 points, you could have an attack that cuts HP in half, round up, if the target misses a HT roll. I'd say it affects current positive HP; at 1 HP or below, it wouldn't do anything. Thus if a fighter with HP 16 were currently at 13 HP, the first zap would make it 7 HP, the second zap would leave 4 HP, the third would leave 2 HP, and fourth would leave 1 HP, after which nothing would happen.

Damage Reduction (Injury Tolerance) starts at 50 points and then goes 25 point increments to divisors.

Homogenous and Unliving and such don't affect all damage types so I would probably go to a higher % otherwise that works pretty well.

However, this has farther reaching affects. He's looking to actually do damage, this is an affliction which lowers max HP in general.

Shock Penalties, Knockdown checks, Crippling, etc all comes with actual damage which wouldn't come with dividing hit points.

IS that important to him? I don't know.

[Bathawk]

What your describing is a variation of an "absolute" (Powers p.117-119)...it's one thing if you do "50% of HP" on a street thug....quite anotherto do 50% HP damage" on Galactus

I would start by determining the absolute maximum amount of damage your power can do. For example a 200 HP opponent you can do a maximum of 100 points of damage

assuming a "bio" attack 100pt's of toxic damage would be equal too (100 x.3) 30 dice of toxic damage (120pts.)

Next for your "percentage" use the accessibility chart on Powers p.99....50% of max HP would be a -20% limitation =96pts.

[whswhs]

Originally Posted by Kromm

So for 97 points, you could have an attack that cuts HP in half, round up, if the target misses a HT roll. I'd say it affects current positive HP; at 1 HP or below, it wouldn't do anything. Thus if a fighter with HP 16 were currently at 13 HP, the first zap would make it 7 HP, the second zap would leave 4 HP, the third would leave 2 HP, and fourth would leave 1 HP, after which nothing would happen.

If you rounded down, then starting from 13, you would go to 6, 3, 1, and 0. That's marginally faster (going by when you reach 1) and it works like the way halving works for required times (for example, for changing shape); and subjectively I find it a little neater. But it still has a natural stopping place, at a quantity of damage that can't kill you—just knock you out.

[kirbwarrior]

Originally Posted by Bathawk

What your describing is a variation of an "absolute" (Powers p.117-119)...it's one thing if you do "50% of HP" on a street thug....quite anotherto do 50% HP damage" on Galactus

I would start by determining the absolute maximum amount of damage your power can do. For example a 200 HP opponent you can do a maximum of 100 points of damage

assuming a "bio" attack 100pt's of toxic damage would be equal too (100 x.3) 30 dice of toxic damage (120pts.)

Next for your "percentage" use the accessibility chart on Powers p.99....50% of max HP would be a -20% limitation =96pts.

Actually, this is a good start. One thing I would add (to give a feel that you can't affect certain targets) is to add a limitation to reflect that if it doesn't do enough damage, it does none, so it's "restricted" to targets with low enough HP (and thus no one has to worry about Galactus, the planet, or other super beings being affected)

[Anthony]

Originally Posted by Bathawk

Next for your "percentage" use the accessibility chart on Powers p.99....50% of max HP would be a -20% limitation =96pts.

Though what he wants is a percentage of current hit points, which is significantly more limiting, as it means the character can be weakened but not finished.