No, it really isn't. It takes most of a round to cast a typical spell. Some spells may even take so much longer that you need Concentration, Sun, or maybe even Moon to cover them. If what you are saying were true, these longer Durations would be unnecessary with MuVi.
This is obviously untrue in the core book. Just look at the things that can happen while you are casting a spell that might cause you to lose concentration. If it's in an instant, how can you get knocked down while casting, for instance. You're confounding when a spells goes off with the time spent casting the spell, probably because they tried to simplify combat rounds.
... the effect of which is that the casting is reduced to an instant of the narrative and what I said is true in the core book, as far as the narrative goes ...
Unfortunately, this makes it harder to incorporate distractions in the combat sequence. Don't blame me, I did not write the rules.
However, the details of this discrepancy in interpretation only matters when you want to (ab)use this putative duration of the moment to enable a continuous effect, which was OP's question. Precise time does not matter at all; narrative time is closer to Augustin than modern physics.
You start by assuming that a spell with Momentary duration takes effect immediately after which the magic is gone. From this you draw weird conclusions on how long casting must take.
Usually when the conclusion looks wrong, it is either the logic or the assumptions that are wrong - in this case the assumption.
Assume instead that a spell with Momentary duration can last as long as a few rounds - and suddenly spellcasting and various Momentary spell work just fine as written, making this a much more reasonable assumption.
Are you asking about a medieval moment, modern moment, or a high speed moment? Because they are all different things.
A medieval moment was a unit of measurement for the movement of a shadow on a sundial, dating back to at least the 8th century. While the actual length of it varied based on the time of year and latitude of the location, it averaged at roughly 90 seconds. That average was what was used when a "moment" is used in medieval speech and text. The "moment" was a quarter of a "minitum" (itself one tenth of an hour), or 12 "ounces" (of 7.5 seconds each).
A modern moment is currently a "short period of time", which can vary from 1.5 seconds (a breath) to just an undefined period up to a minute long depending on use case. This is the common use in modern society.
A highspeed moment is roughly the same as an augenblick/blink of an eye. It takes about 0.3 seconds. This is the meaning when used in highspeed operations to mean a short delay.
A moment is not an instant. Even in highspeed operations such as with computers there is a difference between the two.
In AM, if we use the modern moment then it can mean anything from 1/4 rounds to a minute/10 rounds. If we use the historical term which is what was used at the time then it is 1.5 minutes/15 rounds. Most likely the designers meant the modern moment, though the historical one would be appropriate for "in character" speech.
Well, the "medieval moment" seems a bit too close to the diameter to be worth having as a separate duration, so I think we can discount that as the intended meaning. (Plus, few people will ever have heard of that meaning.)
The "highspeed moment" sounds like a term used in very specific circumstances only. Not something likely to be used in normal writing without specifying it clearly.
Yes you will generally only find the "highspeed" version used in technical writings.
I do believe that the designers were using the "modern" moment when the game was designed, which would give a range of a 1/4 round up to 10 rounds. This actually fits the variations of time found in varies published spells.
The "medieval" unit, which is an actual defined measurement of time, would be best used for "in character" speech since it was used up until the water clock overtook the sun dial in the late 13th century.
Now you switch context. I never objected to any of the canon spells, which stretch the instant in various ways. Look at how they work in the narrative. The effect is singular. When the instant is dragged out in time, it is cosmetics and flavour and not extending the effect. That is very different from saying that the effect has duration so that you can achieve constancy by repeated casting.
Are you arguing that a player can design a custom spell with momentary duration lasting several rounds? Say a ward spell which lasts Ā½ min (five rounds) saving a magnitude compared the the 2 min version with diameter but doing better than the canon momentary wards which typically deflect a single attack?
That would be the immediate consequence of the assumptions you make, and I do not like this conclusion any better.
I don't buy the concept of "stretch the instant". No such thing in my world.
Perhaps not that long, but Momentary effects that can last up to 2-3 rounds in some cases - all depending on what the spell does.
I would certainly allow a Momentary spell that deflects all attacks for the rest of that round. That spell might well require an additional magnitude for extra complexity compared to a single-attack deflection spell, so one might not gain much compared to using D:Diameter.
No, not at instant of the narrative. It's reduced to a single instance of statement at the game table, just like rolling a die is. If I roll a single die at the game table to climb 100 m, does that mean I can climb 100 m in the time it takes to roll that die? The whole mechanic of declaring a spell early and then resolving it later means you have to go around the table at least two, sometimes more times, to resolve each round of combat. The writers sought to do away with that nuisance. The does not mean the narrative, if we extend what you're saying, is that knights stand still for nearly all of a battle except for some near-instantaneous swings of swords and blocks with shields.
That makes it equivalent to a custom duration Ā«turnĀ» according to the standard rule that custom durations have the same magnitude as the shortest canon duration not too short. Fine.
What is the consequence to OP. Can you chain together momentary spells to make a continuous effect with an environmental trigger and unlimited uses?
If that's the time it takes in the story, yes, of course. We are not running a physical simulation, are we? The physical timeline, as a measurable space in the mathematical sense, does not dictate the narrative timeline.
But let me ask you the same question as I asked Erik. Would you allow PC magi to invent momentary spells with a duration extending to (say) Ā½ min/5 rounds? Just because a moment for spell purposes can be that long?
And then. what's the implication to OP's question?
No, there are multiple canonical spells that are active across as much as 3 rounds that are Momentary. So why would lasting a single round be too long for Momentary?
I don't know where the cut-off should be. But we know canonically it is at least 3 rounds, as there are multiple spells that continue their magic over 3 rounds and are Momentary. So if you had asked for 18s (3 rounds), I would say yes because the rules already allow that. Where the cut-off is beyond that becomes more questionable.
If you don't allow Momentary to handle an entire round because Momentary can't last that long, then you are using a house rule.
You confound two different issues; singular spells which take some time to build up and fade out, and spells which sustain an effect for a round or more. While I am aware of several examples of the former, I cannot remember a single example of the latter. Allowing the latter based on precedence for the former is as much a house rule as barring it it. If you have a canon example for the latter, please share.
Looking at Creeping Chasm (ArM5 p156), it has D:Momentary, yet the created chasm takes 7-8 rounds to reach maximum size, strongly suggesting the spell lasts that long.
No, I really don't. Take a look at Earth Split Asunder (ArM5 p.156). Tell me if that's really a single effect taking a while to happen. Meanwhile, Heat of the Searing Forge (ArM5 p.140) creates heat (hate that term, but I'll accept it here) that, while diminishing, lasts and does damage over 3 rounds; so the magical heat lasts 3 rounds. That's two cases of the magic lasting for an extended period of time. And there are more that last for shorter amounts of time.
Yes, I'm aware of that spell and its 7.5 rounds. However, some of the timing of the spell is necessarily incorrect (look at the closing), which I pointed out for the errata. When pointing that out I mentioned this 7.5 rounds. So, knowing the spell absolutely needs an erratum, I don't want to use it as an example case until I see the final, corrected version.
I cannot see how you read it that way. It says that it heats a piece of metal, which is then scolding hot for three rounds. There is no suggestion that the magic lasts for more than an instant.
Yes, I misremembered that one; it does actually sustain the effect for one round, but then this spell has spec duration, not momentary ...
The magical heat ceases to be there after the spell ends.
If you think this heats it that hot for a moment and then it cools naturally over this time, even neglecting the lasting Creo bit, please, please, please for your own sake don't trust yourself around really hot metal. Metal this hot does not cool this fast naturally unless you take specific efforts to make it do so, and that was extremely well known around 1200.
Oh, shoot, it's listed two different ways. It's also listed as Momentary.