Magic Resistance & Target:Room

(This topic is a tangent from another thread: https://forum.atlas-games.com/t/getting-around-parma/5906/22 )

The original discussion was about "How to bypass Parma?", and this tangent brings up the question of Target:Room effects...

If an effect is over a large area, for instance Target:Room, and there are creatures (magi, dragons, whatever) in that room with Magic Resistance (natural MR, Parma, whatever), then the effect does not affect those creatures (assuming it does not penetrate the MR) - but it still affects the area, or at least does so as much/if possible.

MR doesn't stop a spell from being cast or taking effect - it merely protects the individual w/ MR (and only them) from being affected by that effect. The spell effect still occurs - it just doesn't affect the individual w/ MR. There is no "spell failure" involved (that's a diff game).

To start, let's take 3 examples... all involve an off-camera caster, and a simple room with a grog and a mage with high** Parma Magica.
(wearing a red shirt, most likely)
(
* high enough that the spell doesn't penetrate.)

Example 1)
Big Bonfire
(CrIg, Duration:Diameter, Target: Individual, Size +3)
Creates a large
fire.
Effect: A fire fills the target area, which does not include the grog or mage.
[list]The caster walks in, and the fire parts around him. The grog walks in right next to the mage, starts to burn, and realizes he's not being paid nearly enough. The effect is not canceled at all, the magic simply does not affect the mage.(* +3 size = maybe 30 paces x 30 paces or more - a BIG fire.)

Example 2)
Big Bonfire (same as above, this time aimed differently)
(CrIg, Duration:Diameter, Target: Individual, Size +3)
Creates a large
fire.
Effect: A fire fills the target area. Here, the caster casts the effect in the room where the grog and mage are waiting. As above, the Parma does not stop the effect except where the mage is standing; other than that, the entire room fires up. The grogs start to burn, the mage just doesn't care, and the fire fills in behind the mage if he moves.
Example 3)
Room of Circe
(As Curse of Circe ()MuCo p 131) but Target:Room)
Effect: Turns all persons in room into pigs
This is no different than example #2*. One part* of the spell is resisted - where the mage is standing - but the rest works fine. Just as the mage's MR doesn't stop the large fire spell, the MR doesn't stop the other part* of this single effect.
(* small "p", not a Target size)[/list:u]
So we see (I hope) that a spell that targets a room is not stopped because a small part of that room (the mage) has Magic Resistance. It's like a drysuit for a scuba diver, keeping water out - the magic is still out there, it just doesn't get in to the mage.

Now, let's get a bit more creative -
Example 4: The T:Room effect is a large PeAu, to remove all the air. The ensuing vacuum breaks eardrums and causes a loud, thunder-like explosion as the air rushes in and stuns everyone within*. The grog is deafened and stunned, the mage sees what happens but suffers no immediate effect** from the magic. We disregard "physics" here - this is magical, and modern physics need not overly concern us - the Story is what is important (and consistency of interpretation, and fun, etc.). Maybe "stuff" gets sucked into the vacuum and batters the mage - or maybe that, too, is ineffective against the Parma - up to the SG.

(* We'll assume the spell is sufficiently large to achieve this effect, and the SG approved it. Ysmv)
(** It is pointed out, below, that in canon (p 86) the mage is stunned - depends if you feel that "concussion" is magical, or a secondary effect of the magic, like the effect below...)

Now, let's take yet another variation, example #5...

This time, it's a large PeTe that removes the walls of an entire Structure. This has nothing to do with the mage - so the walls disappear. And the mundane roof comes crashing down... and the grog and mage are both in trouble. (Note that this may or may not contradict any "stuff flying into the vacuum doesn't penetrate" ruling from the previous example - it's good, but often hard to take rulings to their logical conclusion. Try to take things to an extreme when such rulings are called for, if possible.)

Now, there are some situations where the issue is less clear, and require SG interpretation. What if (example #6) the floor were one slab of stone, and moved upwards to the ceiling? In an "all or nothing" situation, then I would say (ysmv) that the MR prevents the spell from working. (Some SG's might rule that the floor break, and only the small section that the mage is standing upon is not be affected - that works too.)

Lastly, if (example #7) an entire drawbridge or stone castle wall were magically thrown down on a mage, the magical force would not penetrate - but (arguably) the mundane weight of the bridge or wall still exists. The fact that it has an enchantment on it does not negate the mundane effect - this is a variation of the "pink dot" effect. The magic cannot crush the mage, but nor does the existence of the enchantment save the mage from the obvious - being crushed by the mundane weight of the drawbridge or wall.

There are endless variations, magical bridges and magical holes and magical sandals and magical quicksand so on - but the idea is the same. Magic should not penetrate MR, but MR does not stop magical effects around the mage. A mage can stand in the middle of a magical fire, or that magical fire can be cast around him - the fire is not so much "suppressed" as simply cannot effect the mage where he stands - but either way it pops up again after he moves.

You can't create light at room target, you need individual or group target. See "target and creo".

Urgh!!!!

But it was such an elegant example!!! :frowning:

Right - changing...

(And I had just quoted that same section not half an hour ago!)

<Rego Corpus: KIck - R: Personal, D: Momentary, T:Part> : :blush:

Edit - Fixed. :unamused:

Air destruction is a canonical example of an indirect effect that will harm Magi despite their magic resistance. (ArM5 dead center of page 86, last bulleted item on the list.)

(Yeah, good point - and in part that gets back to a diff current discussion, of what affects a creature w/ MR. I'm not convinced, but I may be in the minority here, and won't for a second claim I'm completely in the RAW. Otoh, I'm not convinced that example is perfectly in step with every other rule, depending on its interpretation.)

For me, "some air" still exists within the thinnest layer of the Parma (sim to the "magical quicksand" spell effects), and the mage is not immediately suffocated nor affected by the vacuum - but that's me. As for the resulting concussion - I'll admit that that might be more approp - I'll edit the above to avoid that off-topic confusion, as it's not this discussion. It is like the "remove walls, let the roof fall" spell in that way. Depends if the SG feels the resulting "concussion" effect is magical or not (and imo bringing RL understanding of physics, esp high-speed physics, into a magical explanation is often a huge mistake).

One thing that is true about Ars - the rules are not considerably complex, but they are extensive, and some few unresolved contradictions and situations still lurk in the shadows here and there. In the end, it has to make sense to the SG and the Troupe - if you see a contradiction that isn't a game-breaker, then fix it. If it is a game-breaker, or just jars against the rest of how you see Hermetic Magic working, you need to either revise your view or your reading of the rules.

Very much so since horror vacui, air rushing in to fill an empty space, is the force that replaces inertia and explains persistence of motion in Aristotelian Physics. It's the force that keeps arrows and catapult balls in flight. In theory the medieval paradigm predicts an even larger force resulting from a vacuum being filled then RL fluid dynamics.

I don't know, maybe it is Raw to allow a PeTe T:Room spell destroy all the walls and crush anyone inside, but it seems to run contrary to history of the development of the order and the willingness of magi to enter anything with concrete borders from a magical perspective. Much more the sort of issue that would make them all want to live out in the wild forest, meeting under the stars in a copse of trees with sancta secreted away in private regios. Or just anti-social, hermetic and reclusive, which is exactly what Parma was supposed to counter act.

Personally, I'm going to need more convincing before I move from a basic rule of "Finesse or Penetration". :/.

It is kinda not, PeTe Room will destroy things in the room but not the room itself. A PeTe Individual or Part spell with enough size added on can destroy a stone building but it's not instant death for the magi inside. Where you can't specifically aim anything at him I would allow someone inside rolls to mitigate the damage. Plus the larger the building the longer the implosion takes so the Magi inside has time to react. One or more rounds to cast a spell leaves Hermetic Magi with options.