Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 08-23-2019, 09:29 AM   #1
CarrionPeacock
 
Join Date: May 2018
Default [Powers] Are Multiplicative Modifiers Fairer?

At first glance they seem to be:
Create Fire (Destruction,+100%;PM,-10%)
Default: 10*(1+(1-.1))=19/level
Multiplicative: 10*(1+(1))*(1+(-.9))=18/level

But some powers can become too cheap:
Control Rain (Natural Phenomena,+100%; Immediate Preparation Required (10 minutes),-45%; Requires Magic Words,-10%; Requires Gestures,-10%; Costs Fatigue (1 FP),-5%; PM,-10%)
Default: 15*(1+(1-.45-.1-.1-.05-.1))=18/level
Multiplicative: 15*(1+(1))*(1+(-.45-.1-.1-.05-.1))=6/level

Are cases like the second example still fair and balanced? I'm afraid breaking the system by using it.
CarrionPeacock is offline   Reply With Quote
Old 08-23-2019, 09:59 AM   #2
Seneschal
 
Seneschal's Avatar
 
Join Date: Jul 2009
Location: Pula, Istria, Croatia
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

The power to summon drizzle after a lengthy, tiring ritual is cool roleplay-wise, especially in heavily agrarian societies, but it shouldn't be worth almost as much as raising DX by 1. Multiplicative seems fairer there.

Basically, if you "ruin" your power power by putting lots of limitations on it, then the multiplicative cost will reflect the fact that the power is barely usable anymore. The GM should be careful however, and make sure that the power is actually crippled (as opposed to just super-focused in a way that thethe player can exploit).
Seneschal is offline   Reply With Quote
Old 08-23-2019, 11:13 AM   #3
zoncxs
 
zoncxs's Avatar
 
Join Date: Oct 2010
Location: earth....I think.
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

Example of broken multiplicative.

Super ST (max duration, 30s, -75%; super effort, +300%; PM, -10%)

Normal cost = 31.5 per level

Multi cost = 8 per level

So for 320pts you can get:

ST 20/110. With 5 points to spare.

Or

ST 50/ over 5,000,000
zoncxs is offline   Reply With Quote
Old 08-23-2019, 11:43 AM   #4
WingedKagouti
 
Join Date: Oct 2007
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

Quote:
Originally Posted by CarrionPeacock View Post
Are cases like the second example still fair and balanced? I'm afraid breaking the system by using it.
Even if an ability is technically legal within the rules and setting being used, the GM still has the final word on whether any ability is allowed for whatever reason they want.

I doubt many GMs would consider the example you use an exploit, but doing the same type of math with an innate attack with an area of effect and you could easily end up with something that can circumvent just about any encounter that would be reasonable for the rest of the party.

Something like Crushing Attack (Area Effect (32 yd), +250%; Costs FP (2), -10%; No Blunt Trauma, -20%; Emanation, -20%; Magical, -10%; Takes Recharge (15 seconds), -20%)* would have a cost of 13.5 points per level with Additive Modifiers but 3.5 points per level with Multiplicative Modifiers. A character with 10 levels of this Innate Attack would likely be able to go into an area, explode, then pick up all the loot and proceed to the next room. That might be ok for 135 points, but it feels a bit too good at 35 points unless all party members have similar broken stuff and the challenges are tailored to them having those abilities.

Overall, the GM should always police the abilities the players try to come up with to make sure there isn't a major disparity in what they can do. If you have eg. a barbarian with a good amount of Strength, solid skill and a big sword, they're going to feel useless if paired with a mystic using the above ability at 3.5 points per level. "I swing my sword and deal 3d+4 damage!" (ST 20, Fine Broadsword) feels inconsequential compared to "I walk into a room and deal 10d damage to everyone", especially if the sword swinger likely paid close to 200 points for their feat (ST, DX and Skill) while the mystic paid 35 points (even if they spend 2 FP and need to wait 15 seconds to repeat it).

*The exact limitations aren't important, the fact that they combine to -80% is.
WingedKagouti is online now   Reply With Quote
Old 08-23-2019, 11:46 AM   #5
Mark Skarr
Forum Pervert
(If you have to ask . . .)
 
Mark Skarr's Avatar
 
Join Date: Feb 2005
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

It's a matter of taste. I, personally, prefer Multiplicative Modifers as it allows more powerful abilities on a reasonable point budget. The trade-off is that, the moment you have any enhancements, the abilities' minimum cost is raised.

And, to be honest, there's nothing broken about zoncxs Super ST. It lasts for 30 seconds, then is gone for five minutes. Yeah, it's cheaper but so is almost everything else.

DR 100 (Cosmic +100%, Force Field +20%, PM -10%, Max Dur 1 minute -65%) is 275 points compared to 725 points. That's way more effective than the ST 20/110. It lasts twice as long and can soak anything the ST 20/110 can throw at you. It'll even let a hero absorb the average damage from a car moving 100 mph.

It's not broken, it's different. Everything's value changes. If you're playing with high-point/high-power abilities, MM is, in my opinion, better as it allows you to do more with less. It isn't as effective at low-levels/low-point abilities.

Another advantage of MM is that it keeps people from stacking ridiculous limitations on their powers trying to get their costs under control.

If everyone is using Multiplicative Modifiers, then it's fair across the board. Multiplicative Modifiers actually reflects how limiting the limitations of a power are. This is most apparent with Afflictions:

Take Affliction 1 (Incapacitation: Sleep +150%, Malediction 2 +150%, Magical -10%, Accessibility: Only on Men -20%).
Normally, that ability is 37 points.
With MM it's 28.

Under normal circumstances Only on Men is worth two points per level because it's figured off the base cost of the advantage, which is 10 points. With MM, it's worth eight, because it's figured off of the total cost of the ability's "offensive" capability.
Mark Skarr is offline   Reply With Quote
Old 08-23-2019, 11:58 AM   #6
ericthered
Hero of Democracy
 
ericthered's Avatar
 
Join Date: Mar 2012
Location: far from the ocean
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

Quote:
Originally Posted by zoncxs View Post
Super ST (max duration, 30s, -75%; super effort, +300%; PM, -10%)
There are a lot of ways you can skin that particular cat. Max duration is one of those limitations you really have to watch. Try sticking it on unmodified ST, an innate attack, Jumper, or any of a myriad of advantages useful mainly in short bursts. It just breaks things more evenly now.

With multiplicative multipliers, you do have to be more careful with limitations, and make sure they are actually meaningful. Some GM's have gotten a touch lax with that because players wanted to counter-balance large piles of enhancements and the sweet spot for limitations is in the 40 to 80 percent range. Duration advantages are a common way to abuse this, as are gadget limitations. This isn't to say that they are bad, its to say you need to ensure the limitations are meaningful.

The weather advantage earlier can make you popular and possibly a lot of money, but that's only its an in demand ability or you're rare. As a GM if I see an ability that can be used to make oodles of money I generally require them to purchase wealth or take traits that forbid them from making that money.

I love multiplicative multipliers, and I find they make the range of practical characters considerably wider.
__________________
Worlds Beyond Earth -- my blog
ericthered is offline   Reply With Quote
Old 08-23-2019, 12:01 PM   #7
Anaraxes
 
Join Date: Sep 2007
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

I find MM comes in handy when the game contemplates more significant powers (supers, powerful mages, creatures, whatever). There are a lot of large positive modifiers in the rules (+100%, +150%, +300%), thrown around fairly casually when there's a big increase in utility. Not unjust -- but there's no corresponding set of large negative modifiers (-100%, -150%, -300%) to balance them out.

(Even on the forum, "-80%" is used as shorthand for "almost completely useless" or "having nearly all utility removed". But that's really more a job for "-300%", letting the "nothing below 80%" floor save us from the math. Once you consider more than one positive and one negative modifier on an Advantage, then -80% is no longer a useful cap for individual mods. There's an intermediate calculation to be done.)

The chief drawback to using MM is that all those percentage values were arrived at by experienced judgement, playtesting adjustment, and cross-comparison. There's not a way to just derive a fair, proper value de novo, by breaking individual Limitations down into micro-modifier atoms. And the existing balance of all those numbers (to the extent that they're balanced) assumes that you're using AM. With MM, some of those numbers likely ought to change. There can be wonky builds with AM, but you can probably get more with MM. So it calls for that much more GM/player cooperation and judgement.
Anaraxes is offline   Reply With Quote
Old 08-23-2019, 12:56 PM   #8
malloyd
 
Join Date: Jun 2006
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

No. Nor are they less fair. The central problem is the *modifers* aren't fair. Many of them simply differently beneficial or crippling on different powers, and therefore any system that offers a fixed modifier - whether it's additive, multiplicative, flat cost or anything else - will fail to generate "fair" prices relatively frequently.

You can't "fix" this with a change to a mathematical system of computing costs. Not even for unmodified traits - because the usefulness of absolutely identical abilities can vary wildly with the details of the setting. That's why basically every rule system that ever included a build-your-own ability subsystem has included a GM vetting process or vaguely defined sliding scale modifier he can use to adjust them. Rules lawyers hate those sorts of meta-rules and ignore them, but game designers have been aware of the issue since forever, and know it's fundamentally unfixable with mechanistic rules - it needs a judgement call.
__________________
--
MA Lloyd
malloyd is offline   Reply With Quote
Old 08-23-2019, 01:28 PM   #9
Sunrunners_Fire
 
Join Date: Mar 2010
Location: Bullhead City, AZ
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

Quote:
Originally Posted by CarrionPeacock View Post
I'm afraid breaking the system by using it.
You shouldn't be. The system isn't that fragile. You may get results that look silly to people using the more common additive-modifiers, but they'll get results that look incredibly silly to you too. In practice, the difference between additive and multiplicative modifiers is that using multiplicative modifiers removes the incentive to stack gobs of limitations on your traits in order to reduce the costs to a reasonable value (by making it so that you don't have to stack quite so many limitations to get the same result).

So long as all of the players are using the same method to determine how many points something costs, what that number is does not, has never and will never actually matter. GMs don't use points. NPCs don't use points. Gear doesn't use points. Some of us run games where we don't use points for PCs, either; and that doesn't break the system.

You'll be fine. ;)
__________________
"Art thou wroth? Wherefore art thou wroth, brother?"
Sunrunners_Fire is offline   Reply With Quote
Old 08-23-2019, 01:43 PM   #10
CarrionPeacock
 
Join Date: May 2018
Default Re: [Powers] Are Multiplicative Modifiers Fairer?

Thanks for the replies. I was worried about the this optiona rule because it never became anything more than a footnote on Powers but now I'm more confident about using it.
CarrionPeacock is offline   Reply With Quote
Reply

Tags
powers

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 03:30 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.