Removing the Rule of 16

[tbone]

Originally Posted by Mr_Sandman

In a setting that has supernatural attacks, without the Rule of 16 magic users, psis, etc. could raise their effective skill in one or more spells or abilities to the point that in quick contests it overwhelms the resistance of any characters limited to the human attribute range.

Right, that issue is clear (especially in DFRPG, which spells it out with "This prevents spellcasters from improving a single spell until it guarantees victory!").

But the thing that made me scratch my head was "But why go out of the way to limit a supernatural attack's success roll to 16 or less, when the roll – really, any success roll in the game – is already limited to 16 or less by the critical failure rules?"

And having now thought for a little bit (a rare thing!), I believe I can easily state the answer: The rule isn't going out of its way to limit the success roll itself (which is, indeed, already limited by crits). The rule is going out of its way to limit margin of success.

That is: When the wizard attacks with resisted Spell-28, the Rule of 16 doesn't change whether his spell's roll succeeds or not – it's gonna fail on 17 or 18 no matter what. But it does change the number of points by which he succeeds: if the wizard rolls a 13 but a cap of 16 is in effect, then he succeeds by 3, not by 15. His victim only needs to succeed by 3 to shrug off the spell.

Obvious all along to most readers, I know, but I think I get it now.

[evileeyore]

Originally Posted by tbone

The rule is going out of its way to limit margin of success.

Well yes. Referring to it as an 'attack roll' was probably the confusing issue.


For many of us, we first saw the rule in 3e under "Resisted Spells" so it wasn't 'attack' but rather this (and wasn't called 'The Rule of 16' until the Compendium II came out):

If the subject is a living creature, the caster rolls against a 16 or the subject’s actual resistance, whichever is higher, if his effective skill is over 16 and the subject is a living creature; thus, “automatic victory over resistance” is impossible.

[D10]

Originally Posted by tbone

I was wondering what problem the rule [of 16] is seeking to fix.

Basic Set doesn't make it clear, but Exploits in DFRPG does: "This prevents spellcasters from improving a single spell until it guarantees victory!"

Fair enough. But I still wonder: If a roll of 17+ is considered a critical failure anyway, is it meaningful to specify that some supernatural attack is capped at 16 (or more, depending on the resistance)?

I'm not sure I entirely understand the need for the rule. . . .

Heres a practical example from a campaign I recently played in

I had a wizard with very high IQ and many points invested in the mass daze spell. At one point my skill level with the spell reached 30 and was nearing 35

At that level of skill, the only thing preventing me from dazing dozens of enemies in every battle and making it trivial was the rule of 16.

Even enemies that have very good HT usually wont have a roll higher than 20-24, and without the rule of 16 even they would roll at a disadvantage against me. If you consider the average enemy to have an HT roll of 16, they would simply be massacred in the contest.

At skill 30, if I roll 16, my margin of victory is 14
At HT 16, if someone rolls 5, their margin of victory is 11

So as you can see, the only thing that would prevent someone from being dazed by my caster would be for me to critically fail or for the enemy to have a critical success

But with the rule of 16, it doesnt matter that my skill is 30, rolling 16 means I succeded by a margin of 0, and theres a real chance someone with non-godly HT can resist me.

This shows why the rule of 16 is so powerful, it adds risk and chance to spells that would otherwise be "I win buttons" when theres enough points invested in them, such as sleep, charm, daze, and roll or die spells.

This forces spellcasters to be more versatile, and prevents 1 spell win builds

[Anaraxes]

The problem appears most frequently in standard magic (spells as skills), because those skills really operate on a different scale than most GURPS skills. It's routine for your stereotypical starting mage build to have skill-15 in any spell, for 1 point. Skill-20 is expected for some key spells even for 150-point mages. Skill-25 is not unobtainable with a little experience. Improving spells by +5s is entirely normal -- it's the basis for skill-based energy reductions.

Spell defenses can't really come close to the same levels for anything like the same cost.

When the system is built around a 3-18 roll, numbers are bound to get wonky when they get way over 18. But standard magic is designed with that expectation.

It's not impossible to get other skills similarly high, but that's much more of a stunt than it is routine behavior. The only other case that readily comes to mind would be face characters, because there are an awful lot of influence skill modifiers that stack.

[Gnome]

Originally Posted by Mark Skarr

We have removed it in a number of games. It didn't really change the games in a meaningful way.

It also made games where there are supposed to be incredibly powerful beings feel more powerful.

I think incredibly powerful beings can be more easily distinguished by retaining the Rule of 16 and allowing such beings to break it, or at least raise it to Rule of 17, 18, etc. with the appropriate perk(s).

[Andreas]

Cosmic immunity might be a bit expensive, but magic resistance is rather affordable and is also applicable to all forms of resisted magic.

Originally Posted by Gnome

I think incredibly powerful beings can be more easily distinguished by retaining the Rule of 16 and allowing such beings to break it, or at least raise it to Rule of 17, 18, etc. with the appropriate perk(s).

That might fit if the setting has a clear cutoff point between powerful beings and the rest, but very often there is rather a continuum in ability without such sharp distinctions.

The rule also doesn't seem to fit how magic usually works in fiction, and it can be quite counterintuitive for players who aren't very familiar with the mechanics. For example, taking action to improve your magic resistance not actually improving your odds against a specific spell, because there is a huge range of resistive abilitiy where you are a bit more than 50% likely to resist regardless of where you fall in that range.

[Anthony]

The problem is mostly that it's fairly cheap to raise a skill to extreme levels (cheaper in 3e, where this rule originated) and not cheap to raise defenses, so the likely result of allowing uncapped skill on abilities that are one-shots on success is to turn the game into rocket tag.

There are other options, such as just changing powers that are 'resist or lose' to be something else. The problem is a combination of guaranteed hit and guaranteed victory on a successful hit. Alternately, just change the cost of skill so cranking skill through the roof is no longer a viable option.

[AlexanderHowl]

Magic Resistance is cheaper than raising a spell (2 CP/level versus 4 CP/level). A character can purchase Magic Resistance 20 for only 40 CP, so the only thing keeping characters vulnerable to magic is their desire to benefit from magic.

[ErhnamDJ]

I've often pondered changing the quick contest mechanic for these abilities to the attack and defend mechanic, such as what we use with normal attacks. Then the people with high skill would need to take penalties using the equivalent of Deceptive Attack.

Also, I've always found it strange how the Rule of 16 only applies to supernatural attacks. If you can make a mundane version of Mind Control (or Affliction, or anything else), then someone with high skill can just always win.

It's also strange how it only works on the living. If your character is a vampire, or robot, or anything other than a small subset of possible biological creatures, then the rule doesn't apply.

As such, the rule doesn't seem very Universal, which I would hope is a design goal when creating such rules.

[evileeyore]

Originally Posted by ErhnamDJ

If you can make a mundane version of Mind Control (or Affliction, or anything else)...

Since Mind Control is inherently Supernatural*... how do you plan on doing that?


* And not Mundane or Exotic.