What circumstances are Multiplicative Modifiers appropriate?

[PiperHolmes]

Hello all:

I'm finishing up my notes for an upcoming Modern/Myth/Supers campaign, and wanted to get your thoughts on one more optional rule: Multiplicative Modifiers (pg 102, Powers).

It seems like this modifier might be similar to the Super Effort rules from Powers and Supers; the intent is presumably to reduce the CP cost of Supers level campaigns so that players can create characters that simulate the four color strips at a cost efficient price point.*

Obviously if the decision to use multiplicative modifiers is made, it applies across the board. No taking such a character to an additive campaign without significant rework, for instance. And presumably a significant, campaign appropriate Unusual Background would apply**.


*e.g. a 300% enhancement combined with a 20% limitation equals 3.8*base cost in an additive modifier calculation, whereas 300% enhancement with a 20% limitation in a multiplicative modifier scenario is 3.2*base CP cost of advantage.

** To unlock the supernatural abilities in general. That UB could be on a descending basis, based on what level of access to supernatural advantages are unlocked.

[ericthered]

I'm probably on the more aggressive side when it comes to multiplicative modifiers. I generally pull it out anytime I see myself working with a powers system. If I've stuck more than four modifiers on anything during campaign prep, I strongly consider using multiplicative modifiers. Cases I already know I may want it:

• Extreme alien Species
• Magic as powers
• Super Heroes
• Some Psi games

[Celti]

My group and I use multiplicative modifiers for all our games, unless it's a quick-and-dirty one-shot using pre-made packages (e.g., Dungeon Fantasy). It's never seemed particularly unbalanced except in a few cases that seem to cater specifically to the RAW modifier system (such as Raise Dead/Resurrection in Divine Favour).

[naloth]

I strongly considered using it, but how Affliction works essentially convinced me otherwise. Using the normal additive modifiers, everything is essentially adds or removes a fixed point amount. You can't really use it to get an advantage cheaper than it would normally cost. Using MM, other modifiers have more a role on how much you're paying than what the Affliction does.

[nudj]

I think MM work much better for accessibility limitations. I like using MM only for that and applying it at the end.

[Anthony]

Really, all modifiers should probably be separately multiplicative (so two +50% enhancements and a -50% limitation multiplies cost by 1.5*1.5*0.5 = 1.125), but doing that is a giant PITA.

[Anaraxes]

I tend to find MM working out better when there are a lot of large Enhancements involved. The rules are pretty free with values like +100%, +150%, +300%, but there are very few Limitations that can counter those values with AM.

[Mark Skarr]

I use Multiplicative Modifiers almost exclusively. I play a lot of supers/powered games and have never seen it to be anything other than a boon.

While you can use it to get the effect of an advantage cheaper than the base cost, the GM should be watching to ensure that any limitations placed on an ability are actually limitations, and preventing abuse of the rules.

[a humble lich]

Originally Posted by naloth

I strongly considered using it, but how Affliction works essentially convinced me otherwise. Using the normal additive modifiers, everything is essentially adds or removes a fixed point amount. You can't really use it to get an advantage cheaper than it would normally cost. Using MM, other modifiers have more a role on how much you're paying than what the Affliction does.

I have the complete opposite feeling. Affliction is one of the cases where multiplicative modifiers make the most sense, because they effect other modifiers that are already on the Affliction. Consider a magic power to turn a person to stone:

Affliction (Paralysis +200%, Extended Duration: Permanent +150%, Malediction +150%) [60]

Now the wizard decides that is too powerful and wants to make it only available during a total solar eclipse, so the power becomes:

Affliction (Paralysis +200%, Extended Duration: Permanent +150%, Malediction +150%, Accessability: Only during eclipse -80%) [52]

The wizard saved a whole 8 points for a power which will be basically useless. The wizard further realizes that any limitations he puts on the power won't give him back many points. Making the petrify power touch only would only give him back 3 points which seems not worth it.

In comparison, if multiplicative modifiers were used, the petrify (only during an eclipse) would only cost 12 points, which seems much more fair.

A problem multiplicative modifiers have is if there are a lot of negative modifiers. With multiplicative modifiers, a power cannot have more than -80% in limitations, even if offset by enhancements.

Personally, I agree with Anthony, that all modifiers should be separately multiplicative, but that would be a PITA. I have toyed with trying to make some kind of hybrid system (use additive modifiers when the modifiers are small, multiplicative when they are large) but that too would be a pain.

[Anthony]

If you really wanted everything multiplicative, you would probably want to assign each modifier a log value (and for that matter, each advantage) and you just sum up everything, then use a lookup table for final cost.

For example, a 5 point advantage would have a value of 7.0 dB, a 50% enhancement would have a value of 1.8 dB, a 20% limitation would have a value of -1.0 dB, so you'd add them up to get 7.8 dB or 6 points. With some tolerance for rounding (its not like the existing values are particularly sacred) you can get it so you're working with integer values. I'd probably want to drastically cull the number and precision of modifiers, though.