An issue with "limited enhancements"

[Bathawk]

hello, I'm trying to adapt an ability from a well known superhero game to GURPS, the ability does fatigue damage, ignoring all armor, but ANY force field DR...even one level blocks ALL damage

the initial ability looks like this:

4d fatigue innate attack (cosmic +300%, no effect against force fields -10%) (156pts.)

But using the "limited enhancements" sidebar for pg.111 of the basic book, it looks like this

4d fatigue innate attack (cosmic {not vs. force fields -10%} +270%) (148pts.)

Not only is the second option cheaper by 8 points, I can still use the attack against those protected by a forcefield, they just get the force fields full protection....while in the more expensive version, it's "all or nothing"

wondering which option makes more sense, and what your thoughts are

[Kelly Pedersen]

Well, for starters, I'd argue that "completely ineffective against force fields" is a bigger limitation than -10%. It depends on how common force fields are in the setting, but since this is a superhero setting, which tends to have force fields around every corner, I'd price this at -20%.

Anyway, you're right that the pricing here is off. I think this is just a case where the GM needs to exercise discretion. I'd say that any enhancement worth more than +100% needs the cost of any limitation applied to it adjusted anyway, in order to avoid issues like this. I'd suggest dividing the value of any limitation by 2 for every 100% the enhancement being limited is worth. So for this one, worth +300%, you'd divide the -20% I suggested above by 4, for a final limitation value of -5%, which means the "limited enhancement" build works out to +285%, while the "Cosmic and Accessibility" works out to +280%, meaning the more limited version is cheaper than the less, and things work out.

[ravenfish]

Yet another point in favor of multiplicative multipliers. This optional rule (it's in Powers on p.102) has enhancements raise the cost of the ability as normal, then sums up the total value of limitations (capped at -80%, obviously) and reduces the total cost (i.e., the cost after enhancements) by that much. At the price of very slightly more complicated math, it produces what to me feel like much fairer costs when high values of enhancements are involved, as well as avoiding this particular issue you have discovered (EDIT: Since a limitation on the trait will reduce both the base cost and the added enhancement cost, whereas a limitation on the enhancement will only reduce the added enhancement cost).

[Nereidalbel]

Perhaps the flavor behind why any forcefield stops the damage may help figure out a way to stat it.

If there is any AoE to the attack, it could be an Area Effect with Contact Agent. Sure, this means a Haz-Mat suit will protect a basic human, but, it's fair to say force fields would stop the attack, too.

[Bathawk]

Originally Posted by Kelly Pedersen

Well, for starters, I'd argue that "completely ineffective against force fields" is a bigger limitation than -10%. It depends on how common force fields are in the setting, but since this is a superhero setting, which tends to have force fields around every corner, I'd price this at -20%.

Anyway, you're right that the pricing here is off. I think this is just a case where the GM needs to exercise discretion. I'd say that any enhancement worth more than +100% needs the cost of any limitation applied to it adjusted anyway, in order to avoid issues like this. I'd suggest dividing the value of any limitation by 2 for every 100% the enhancement being limited is worth. So for this one, worth +300%, you'd divide the -20% I suggested above by 4, for a final limitation value of -5%, which means the "limited enhancement" build works out to +285%, while the "Cosmic and Accessibility" works out to +280%, meaning the more limited version is cheaper than the less, and things work out.

Well I agee in "genre" that force fields are ubiquitous, in GURPS it's a bit more rare. For effectively +1point per level all your getting is protection for your carried posessions (if any) as well as protection for your eyes/ears/mouth, for a character with dr:20-30, spending 20-30 points on such limited utility makes force fields a bit rare in my campaigns....

...still a better value than nictating membrane though

[RyanW]

Originally Posted by Kelly Pedersen

Anyway, you're right that the pricing here is off. I think this is just a case where the GM needs to exercise discretion. I'd say that any enhancement worth more than +100% needs the cost of any limitation applied to it adjusted anyway, in order to avoid issues like this.

The discount you get for a limitation applied to an enhancement should probably be capped in the same way Temporary Disadvantage is. For simplicity, say that if the base enhancement is +80% or more, it subtracts 4/5 the limitation value directly from the enhancement cost instead of multiplying.