Some questions about metamagic and multipliers

[ATHATH]

If I hit an undead creature with a Fireball with the Energize Spell and Empower Spell metamagics applied to it, what's the damage multiplier for the damage to that undead creature if it fails its save? If it succeeds on the save (and thus takes half damage from the spell)?

If I'm a divine caster who has qualified for the Arcane Thesis feat via the Southern Magician feat, do I only get the metamagic reduction if I prepare or cast my Arcane Thesis'd spell as an arcane spell?

[Goaty14]

If I hit an undead creature with a Fireball with the Energize Spell and Empower Spell metamagics applied to it, what's the damage multiplier for the damage to that undead creature if it fails its save? If it succeeds on the save (and thus takes half damage from the spell)?

I've been told that metamagic feats apply separately (that is, they apply in the most favorable order, and not simultaneously). So you'd deal +x1.5 and then +x1.5.

Say you have a lucky day and roll 34 for your fireball's damage dice. Empower Spell applies: 51, Energize Spell: 76 (numbers round down) for that total. If the undead creature makes their save, they take 38 points of damage.
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The spell wouldn't have to be prepared using southern magician, because the text doesn't say that it has to be cast as an arcane spell, just that when you "cast the spell"

That said, questions like these should probably go to the RAW thread.

[Venger]

If I hit an undead creature with a Fireball with the Energize Spell and Empower Spell metamagics applied to it, what's the damage multiplier for the damage to that undead creature if it fails its save? If it succeeds on the save (and thus takes half damage from the spell)?

If I'm a divine caster who has qualified for the Arcane Thesis feat via the Southern Magician feat, do I only get the metamagic reduction if I prepare or cast my Arcane Thesis'd spell as an arcane spell?

you apply both multipliers, like normal, depending on the target:

undead, fail: normal damage *1.5 * 1.5, or normal *2.25
undead, pass: (normal damage *1.5 * 1.5, or normal *2.25)/2, or normal damage *1.125

you get the reduction all the time. you've already qualified for the feat.

[Crake]

you apply both multipliers, like normal, depending on the target:

undead, fail: normal damage *1.5 * 1.5, or normal *2.25
undead, pass: (normal damage *1.5 * 1.5, or normal *2.25)/2, or normal damage *1.125

you get the reduction all the time. you've already qualified for the feat.

would this not trigger the dnd abstract numbers multiplication rule, where x1.5 + x1.5 = x2? I feel like it would.

[AvatarVecna]

would this not trigger the dnd abstract numbers multiplication rule, where x1.5 + x1.5 = x2? I feel like it would.

Seconded, especially since this weird multiplication rule (really, it's an addition rule they make out to be multiplication that makes it easier to describe the individual rules) basically only ever applies to damage. Empower spell doesn't deal x1.5 damage, it deals +50% damage. This just basically never matters except when it's interacting with other damage stuff.

[Khedrac]

To a fair extent the answer is "DM's call", but we have some examples on which to bse that DM's call.
In addition to the ones given above, there is the RAW answer to empower plus maximize which equals "max + half rolled".

I.e. for a maximised empowered10d6 fireball: 60 + (10d6)/2
(Note 5d6 is not the same thing as half of 10d6, it is very close but it has a different probability distribution, very few will complain if that is hwat you roll, but it is not RAW.)

Despite this example, I would go with the "they stack" rule for empower + energize, not because of the undead, but because of the non-undead!

[Venger]

would this not trigger the dnd abstract numbers multiplication rule, where x1.5 + x1.5 = x2? I feel like it would.

No.

Seconded, especially since this weird multiplication rule (really, it's an addition rule they make out to be multiplication that makes it easier to describe the individual rules) basically only ever applies to damage. Empower spell doesn't deal x1.5 damage, it deals +50% damage. This just basically never matters except when it's interacting with other damage stuff.

If that's a rule, please cite it. I've never heard of it before.

[AvatarVecna]

No.



If that's a rule, please cite it. I've never heard of it before.

Link

Sometimes a rule makes you multiply a number or a die roll. As long as you’re applying a single multiplier, multiply the number normally. When two or more multipliers apply to any abstract value (such as a modifier or a die roll), however, combine them into a single multiple, with each extra multiple adding 1 less than its value to the first multiple. Thus, a double (×2) and a double (×2) applied to the same number results in a triple (×3, because 2 + 1 = 3).

When applying multipliers to real-world values (such as weight or distance), normal rules of math apply instead. A creature whose size doubles (thus multiplying its weight by 8) and then is turned to stone (which would multiply its weight by a factor of roughly 3) now weighs about 24 times normal, not 10 times normal. Similarly, a blinded creature attempting to negotiate difficult terrain would count each square as 4 squares (doubling the cost twice, for a total multiplier of ×4), rather than as 3 squares (adding 100% twice).

Link

Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results. Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage.

Additionally, because the designers think we're idiots (or at the very least, were trying very hard on this particular issue to make sure nobody could claim they didn't know about the rule), they tended to list how this rule applied in most cases where it was directly applicable. Here's an example from Core:

A lance deals double damage when used from the back of a charging mount. It has reach, so you can strike opponents 10 feet away with it, but you can’t use it against an adjacent foe.

While mounted, you can wield a lance with one hand.

When mounted and using the charge action, you deal double damage with a melee weapon (or triple damage with a lance).

This is - to use the phrase that usually gets thrown around when these rules come up - is two doublings combining to make a tripling. This is because these "doubling" mechanics aren't actually "x2", but rather "+100%".

[Venger]

so basically following the same logic, you take (1.5 - 1) as the value imparted by empower and the same for energize, so each adds .5 the spell's original damage. in this instance I'm assuming we roll the damage for the original spell only once and then double it.

[AvatarVecna]

so basically following the same logic, you take (1.5 - 1) as the value imparted by empower and the same for energize, so each adds .5 the spell's original damage. in this instance I'm assuming we roll the damage for the original spell only once and then double it.

Indeed. This would also mean that the Empowered Energized spell dealt 100% damage to living targets (as opposed to 75%).