[Powers] Are Multiplicative Modifiers Fairer?

[Celjabba]

In Pyramid 70, Kromm have a small box about MM.

In particular,

The GM decides which model to use. The results aren’t the same (although they’re close for small modifiers), so using both isn’t recommended.
The additive model is a good “default,” but the multiplicative model can be fairer in campaigns where huge enhancements (like Cosmic, +300%) occur routinely.

This is a boxed-off “bonus item” because I’m not completely sure that we could have put it in the Basic Set. Adding it would have meant rethinking the value of every last enhancement and limitation – a matter of time more than one of space. If we had had more time, however, something akin to this rule would have made the cut.

So, You do need to check some modifiers. As suggested above, duration limitation are probably candidate for a revision under MM.
That sqid, I sometimes use MM and with a few "on the fly" adjustement, it work perfectly as long as you don't mix both systems.

[AlexanderHowl]

I think that MM is unbalanced if you allow for than one limitation or powerful limitations. For example, if I take a Crushing Innate Attack Backlash, Ecstasy, Resisted by HT (-50%), Cosmic, Irresistible Attack (+300%), Cosmic, No Dice Roll Required (+100%), Melee Attack, C (-30%), No Blunt Trauma (-20%), No Knockback (-20%), and No Signature (+20%), I end up with an additive modifier of +300% or a multiplicative modifier of around 2.15, which translates to a difference of 9 CP/level for an invisible power that will never miss and will ignore all armor (20 CP/level versus 11 CP/level)

[Celjabba]

Originally Posted by AlexanderHowl

I think that MM is unbalanced if you allow for than one limitation or powerful limitations. For example, if I take a Crushing Innate Attack Backlash, Ecstasy, Resisted by HT (-50%), Cosmic, Irresistible Attack (+300%), Cosmic, No Dice Roll Required (+100%), Melee Attack, C (-30%), No Blunt Trauma (-20%), No Knockback (-20%), and No Signature (+20%), I end up with an additive modifier of +300% or a multiplicative modifier of around 2.15, which translates to a difference of 9 CP/level for an invisible power that will never miss and will ignore all armor (20 CP/level versus 11 CP/level)

Actually, with MM, the cost is 6/lvl. You have over 80% of limitations, so you multiply by .2 the cost with enhancements (26/lvl).

A note : I would not allow 'no blunt trauma' on an attack that ignore DR. That limitation does nothing.
The additive would end a bit more expensive [21], no change for the multiplicative as you are above the limitation cap anyway

But the real point of MM is to make limitations actually worth taking :

Here, you have here a potent attack, yes, but one that have the potential of incapacitating you for several minutes each time you use it. Is the limitation worth it ?

With additives, If you don't take the backslash, the cost is 24 instead of 21 ... why take the dangerous backslash for such a small gain ?
With multiplicatives, the cost is [6] with the Backslash, [13] without ... Now it make sense to take the limitation !

Of course, you would need to reassign limitations values, per the Kromm quote, as [6] is a bit cheap indeed !

[AlexanderHowl]

Yes, I forgot that you sum and then multiply. MM makes it even more unbalanced then. Remember, this is a per level cost. Imagine a 15 dice attack, it would cost 300 CP with additive and 93 CP with multiplicative.

[Sunrunners_Fire]

Originally Posted by AlexanderHowl

Yes, I forgot that you sum and then multiply. MM makes it even more unbalanced then. Remember, this is a per level cost. Imagine a 15 dice attack, it would cost 300 CP with additive and 93 CP with multiplicative.

Assuming you're talking about this?

Crushing Innate Attack Backlash, Ecstasy, Resisted by HT (-50%), Cosmic, Irresistible Attack (+300%), Cosmic, No Dice Roll Required (+100%), Melee Attack, C (-30%), No Blunt Trauma (-20%), No Knockback (-20%), and No Signature (+20%)

• If using Additive Modifiers: [5/level] * (1 - 0.50 + 3.00 + 1.00 - 0.30 - 0.20 - 0.20 + 0.20; floor 0.20) = [5/level] * (4.00) = [20/level]
• If using Multiplicative Modifiers: [5/level] * (1 + 3.00 + 1.00 + 0.20) * (1 - 0.50 - 0.30 - 0.20 - 0.20; floor 0.20) = [5/level] * (5.20) * (0.20) = [5.2/level]

If I'm buying 15 levels of your innate attack, at the above prices, then I'm spending either [300] (Additive) or [78] (Multiplicative) for it. I'm also taking too many limitations on the attack if we're using multiplicative; everything past -80% (of which it has -120%) does nothing.

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Which, if your character is using additive and my character is using multiplicative does result in an incredibly ugly situation! But that doesn't happen. Our GM isn't using both additive and multiplicative modifiers in the same time. There isn't an imbalance between two characters when they both spend the same amount of points for the same ability.

I can roflstomp the universe for [50]~ using additive modifiers. (It actually comes out more expensive if using multiplicative!) Having to spend [300] for the ability to maybe whack one dude a second feels ... well, it feels like I'm being cheated.

[a humble lich]

I think it is important to remember that with both multiplicative modifiers and additive modifiers there are situations where the point cost is off. Consider the power:

Innate Attack 1pt burn (Area Effect 32 yd +250%, Cosmic: Ignores DR +300%, Cyclic 1s interval for 10 cycles +1000%) [25]

Which makes everyone in a large area burn in their souls. If I wanted to add the limitation "Only at midnight on the winter solstace -80%" the power becomes nearly useless. With multiplicative modifiers the cost becomes [5], with additive modifiers it is [24]. A 1 point reduction in cost for a limitation which makes the power nearly useless seems wrong for me.

In my view, multiplicative modifiers are better in theory, but I feel most of the enhancement/limitation costs were designed/playtested with additive modifiers so in practice they tend to give better results. I have toyed with the idea of using multiplicative modifiers for afflictions, because afflictions often end up with a large number of enhancements which then makes taking limitations on them not worthwhile.

[Seneschal]

Hmm, I realized from the last few posts that I don't remember how GURPS multiplicative modifiers work - I had assumed they were calculated like in the HERO System, where:

Enhanced cost = base cost x (1 + enhancements)

Limited cost = enhanced cost ÷ (1 + limitations)

That way, there's no need to have an 80% maximum on limitations. However, modifiers also come in chunks of ±¼ in HERO, so you end up with an enhancement total of "+3" or a limitation total of "-2½", which is easier to plug into that formula.

Anyway, given the flexibility of GURPS modifiers, a GM serious about maintaining balance should do more than just set a CP total and check if powers are "legal" - it's also important to sets a range for traits and modifiers allowed in the campaign. Much like a realistic setting sets a "human maximum" for attributes, a GM could forbid powers that have a base cost above 50 pts, have more than +150% worth of enhancements, or more than two limitations, or veto specific combinations of modifiers. As was pointed out already, you can make a universe-destroying attack for cheap even with additive modifiers; it's the GM's job to spot such abuses (and it's the player's job to not be a jerk about it).

[WingedKagouti]

Originally Posted by Sunrunners_Fire

Having to spend [300] for the ability to maybe whack one dude a second feels ... well, it feels like I'm being cheated.

On the other hand, that's closer to what you have to pay if you're using your Strength, Dexterity and Skills to deal damage to others and want a good chance at downing one enemy per turn. Additive Modifiers is better balanced compared to baseline stats.

Also M.U.N.C.H.K.I.N. (despite being a solid attempt at very broken usage of Limitations) is not RAW legal since Emanation and RoF are mutually exclusive, and the ability needs Emanation to not nuke the user and RoF to deal the damage.

[Sunrunners_Fire]

Originally Posted by WingedKagouti

On the other hand, that's closer to what you have to pay if you're using your Strength, Dexterity and Skills to deal damage to others and want a good chance at downing one enemy per turn. Additive Modifiers is better balanced compared to baseline stats.

I disagree.

However! That conversation (characteristics vs skills vs advantages) dives headfirst into a shallow pond full of murky waters and very sharp rocks. IME, it is one of those evergreen arguments that never goes anywhere useful as we've all different experiences and different playstyles which strongly influence our opinions on the subject.

And, so, thereby, I'll bow out of the thread and leave y'all to it.

[Gold & Appel Inc]

* SPENDS 3 FP TO SUMMON M- * Oh, wait...

I'm mostly with the pervert, for his reasons. The only time I don't use MM is when I think the players involved would prefer the greater simplicity. We have GMd and played in each others' supers games and are probably a pretty good testing ground for this discussion, actually.