The spell design rules have the following paragraph:
Each category of Range, Duration, and Target is described below. The categories described here were built into the structure of Hermetic magic by Bonisagus. All Spontaneous spells must conform to these requirements (the magus is making the spell up on the fly—he cannot also push the limits of magic theory). Formulaic or Ritual spells, on the other hand, can be invented with Ranges, Durations or Targets that are not listed here. This is usually slightly more difficult than if the closest category were used, but is largely left to troupe interpretation.
What does this MEAN ?
Can a person with access to a non-standard spell parameter, from a Mystery, use it when casting a spontaneous spell? Or only formulaic ones?
Many mysteries provide alternative spell parameters. Just allowing any magus to invent spells with them seems against the grain. Does the above rule mean that someone with such knoweldge can invent formulaic spells with a mystery-granted spell parameter? And the last sentence is just general advice on setting a new spell parameter's cost ?
I believe it means that, freed from the time-pressure of adjudicating a spont. spell during a play session, and our characters given a whole season to fiddle around with the magic, Formulaic or Ritual spells can have much more imaginative/interesting parameters - but we're supposed to use that freedom to make spells that are more fun, not more powerful.
My troupe often allows non-standard spont spell paramaters, if they're something that's clearly fitting with the mage's magic (something to do with their focus, probably) and the cool-to-power ratio is high.
Unless there's some specific reason not to, I'd say, "Yes. Definitely."
I think the Mystery Virtues represent special knowledge that other magic might emulate, but not really match. So while a faerie magic spell might be 25th level with a "Year and a Day" duration, I'd make a Hermetic spell 30th level, at least, to achieve the exact same duration, because it's a awkward, unnatural unit of time for Hermetic magic. OTOH, the Hermetic "Year" version would be 25th level.
Isn't there a Mercurian "Road" range? And maybe faerie magic might have "Trod" ...
I wouldn't allow a standard Hermetic mage access to either. But I can imagine an extra-magnitudes variation of "Arcane Connection" that gives the same effect. And maybe the spell also requires a sample of dirt from the road for every quarter-degree of arc ... (I think that's roughly a number of kilometers equal to the number of grams in an ounce.)
We assume that's the case, though it's only spelled out explicitly for some RDTs (such as those from Faerie Magic).
No. The idea is that you are not bound by standard RTDs with Hermetic Magic, just as you were not bound by them in previous editions when they did not exist (you eyeballed what seemed reasonable, something that I have come to miss over the years). Porting this aspect over to 5th edition was crucial to maintain many legacy spells.
However, even in 5th edition:
a) you are bound by standard RTDs when using Spontaneous Magic, which simplifies playing the game: when you invent a new formulaic spell, you have all the time to negotiate with the troupe what its actual effects are going to be, but if you are sponting something in the heat of a battle, that could bog down the gameplay.
b) non-standard RTDs are not meant to be a shortcut to power, so troupes are advised to be a bit on the stingy side.
When you gain RTDs from Virtues, the two limitations above are removed: you can use those RTDs in spontaneous magic, and they can be a little (or a lot!) more efficient than standard ones, particularly in niche situations.
It means that a magus can invent a formulaic or ritual spell that uses some other Range/Duration/Target than the standard ones. Subject to SG/troupe approval of course.
He does not need access to non-standard spell parameters from some mystery or similar to do so.
He can however not cast spontaneous spells with non-standard parameters.
A magus who does have access to non-standard spell parameters through some mystery or similar can use them, both for formulaic/ritual spells they invent and for spontaneous spells.
The thing is, allowing magi to use mystery-granted ranges, durations, or targets generally does reduce the mystery's power and uniqueness. Perhaps that's why I thought maybe the stricter interpretaiton might be the one intended. I find it very inappropriate for a magus to invent an Until or Bargain spell without Faerie Magic, or to use the Sabbath duration without Holy Magic, or so on. Even if it's not for spontaneous spells, and even if it costs an extra magnitudes or two.
And I couldn't find an actual example of this in use, anywhere in an official product.
It's a shame this isn't spelled out clearly.
This was my first reading too. But I didn't find a spell that actually used this option, so I assumed I was mistaken. Do you know of any such spell?
But why not? If magi can just invent spells with non-standard parameters, why can't a magus not of these traditions simply invent a spell with a "nonstandard" range that is functionally identical to the Road rnage? And just treat it as, say, Arcane Connection +1 magnitude.
The rules is very vague, but I fail to see why this isn't a very reasonable application of it.
Spells with non-standard parameters?
Some examples are:
The Bountiful Feast (CrHe 35)
Wind at the Back (ReAu 5)
The Impassable River (ReCo 60)
Trackless Step (ReTe 10)
In particular, The Impassable River (from Transforming Mythic Europe, p45) should be instructive:
The Impassable River
ReCo 60
R: Touch, D: Moon, T: Special, Ritual
This ritual turns a river into a magical boundary that cannot be
crossed by man, woman, or child. It cannot be crossed from either
side and those who try may reach midway before they are turned
back. Neither bridges nor fords offer any opportunity to cross.
They are, however, left unharmed by the magic and they may be
used once the spell ends. Variants can be created with the Until
(condition) duration or Year, though both of these increase the
level by one magnitude.
Magi can create spells with nonstandard Targets quite freely,
though they are generally not as optimized as if they had first
researched the required Target parameter. In this case, a river is a
special form of boundary and the target is particular to this spell so
the parameter is treated as Boundary +1, as described in Ars Magica
Fifth Edition, page 114.
This ritual is designed to protect lands from invasion or to place
a barrier in war’s path by disrupting the ability of one side or the
other to travel. Magi working with nobles involved in the dispute
may cast such things, even uninvited, to prevent the loss of life and
to give parties the opportunity to talk. The unscrupulous may use
this to cut off lines of retreat, hemming enemies in and preventing
their escape.
(Base 15, +1 Touch, +3 Moon, +5 special based on Boundary)
They erratad The Bountiful Feast ! In the standard core book, the target is Boundary. In the Definitive Edition, they erratad it to Special, making it indeed a great example for this rule.
Trackless Step is, again, changed from the standard core rules. But the Definitive Edition specifically called out to be non-Hermetic, su presumably not built by plain old Hermetic magic using this rule.
Wind at the Back has a Special duration in the Definitive Edition, and a Sun duration in standard but with the note "closest duration to special effect". So it would seem indeed like another great example fo this rule.
The Impassable River is indeed instructive. I haven't read Transforming Mythic Europe closely.
So, this definitely makes it clear the rule is indeed as you say.
I agree with you about Bargain, and Sabbath: "non-standard" isn't a licence to do anything. But there are plenty of other examples that fit the flavour of Hermetic magic fine.
"Until" is a bit of an edge case, I think. A Creo Mentem spell with an Intellego requisite that granted bravery until the target thought of betraying the caster would be fine. But of course the requisites make this harder for a standard Hermetic mage than a Merinita.
I'd similarly agree that some mysteries give you parameters that do things Hermetic Magic can't usually do - Sensory Magic's ability to affect things that have sensed you rather than you've sensed, for example. For those I wouldn't allow people without the relevant Virtue to use them even in seasonal work.
Why not? Because you need to buy a Virtue to access a parameter. Magi without the Virtue not being able to is strongly implied.
Why can't a magus have a functionally identical parameter? They can. That's what I was trying to get across with the discussion of emulation, and the example where standard Hermetic magic has a functionally identical Range.
But it is only functionally identical. The mage isn't simply applying the non-standard parameter.
You might add magnitudes, you might make the caster jump through extra hoops, and you might also situationally waive the requirement.
If Elsmire, a non-Mercurian mage, wants a Road spell, the troupe might simply say "No." They might allow it, but at higher level, they might make him need to assemble some sympathetic or arcane connections, or - because the spell's target is travelling cows and Elsmire has the Major Magic Focus, "travelling cows" - they might allow Road for this particular Formulaic spell at the same level Mercurian magi use. Or a discount even, because he's The Fast Bovine Sorcerer.
Sensory Magic breaks one of the Limits of Magic - the Limit of Arcane Connections.
Those targets would certainly not be possible to use for any magus that hasn't learned the mystery. Or alternatively has managed the necessary Breakthrough/Integration.