This was what I was trying to draw attention to. I recall much discussion long ago in this vein, but I cannot recall the outcome.
bob
@rgd20
The version in your post had T: Ring, rather than T: Ind like Lamp.... That may change things a little, or drastically depending on the outcome of the ongoing conversation.
My opinion is that the T: Ring version would cause everything inside the circle to become a light source, and the species emitted by that area would flow outward without breaking the circle. If you wanted a very large circle, you'd need to add magnitudes for size. Others clearly disagree with me.
1 Like
Light is explicitly not species as noted by the fact that Imaginem does not affect light.
Sure a ring duration light might light the room but it would be trying to bypass the requirement of vis to magically gain a lab virtue. Hence why I think it should either not be able to leave the circle or break the ring duration.
Side note, you don’t need mirrors if you can cover the entire room with the spell, read the description of Lamp without Flame again, there is no source the area is covered in light, if you cast it on an object that object is merely a moveable center of the effect.
or D: Ring???
I don't have the time to participate in this discussion - but at times I fly over it. Anyway, keeping Durations and Targets apart clearly is important.
Height equal to the length of the circumference could work, it gets you 3.14 paces tall
for a 1 pace diameter circle, so ~3m tall, more than enough to fit an entire person in. Fulfils the requirement of "1 pace across covers a person"
Ring isn't a target, it's a duration and you can't use Circle to Create Light so it would have to be Touch/Ring/Ind to create a light source, or Touch/Ring/Group to make many light sources.
Either way I believe the species would flow out of the ring and not count as the target leaving because the light source isn't leaving, just the species.
Is there a requirement of vis to magically gain a lab virtue? Page 122 of Covenants makes no mention of that, just that using non-Ritual spells either adds 1 to Warping or -1 to Safety and that they don't give a bonus when they are spells that use the same Arts as the lab total. Eg: CrIg to make heat and grant the Magical Heating virtue (which is free and is either Excessive or Superior at your leisure) wouldn't give the bonus to CrIg lab totals, but would give you the Health and Aesthetics bonus.
Pg 123 says "A good guiding principle is that anything involving the use of vis, [...] can grant such Lab Total bonuses" so the spending of Vis is only required for that CrIg thing to assist the CrIg lab total. Using CrIg to create Light and grant the Magical Lighting virtue (which boosts Imaginem) is totally fine without vis and you'd get the Aesthetic and Texts bonus, but also have -1 Safety or +1 Warping.
Having dealt with the (allegedly) more straightforward errata, I am coming back to these.
I think there is a consensus that A and B should both be possible, with the choice made at the time of spell creation (not casting). In the case of A, the spell should end if the circle is broken, even if there is duration left. I'm fine with that.
Outstanding questions.
What is the three-dimensional shape? I am still inclined towards the intuitive "is it in the circle?" standard, given that it impossible for the players to measure anything more precise.
What happens with Ring Duration when part of the target leaves the circle? I cannot help feeling that allowing the effect to continue will have serious abuses, but I could be convinced to allow the effect to continue if there were good examples where it seems just wrong to have the spell fail at that point.
1 Like
How much does it take of the target leaving the ring? If a hair from a human in the circle (targeting said human) floated out of the ring, that is part of the target leaving the circle.
I would say that's fair. In folklore, people really try to avoid sticking a toe out of magic circles -- in fact, try to keep well inside -- rather than stretching out like baseball players trying to just keep one toe in.
1 Like
Is the hair still attached to the human? If not, it is no longer a part of them, so no problem. If it is, then, as @ezzelino says, it is arguably mythically appropriate for the spell to end.
I'd need a clearer example to be convinced that this is a fatal problem for this approach.
Does anyone have further comments? If not, I will write up specific errata/clarification notes based on what I said above, and post them for comment.
I still look with disfavour at the vague "inside the circle means inside the circle" definition, and I think the "cone or cylinder, degenerating to a flat disc when the circle is vertical" is better.
But if that vague definition stays, it should be complemented by a few examples that should give at least some intuition of how you think common borderline cases should be dealt with (e.g. circles lying on a vertical plane, circles lying on an inclined plane, stuff somewhat above or below the circle).
Let me finally add that some of this impacts Circles but also Boundaries and some open-roof Rooms/Structures (e.g. a walled garden is a Room: how high etc.?), so ideally the errata should manage to make the connection (unfortunately, I have no idea how to do it 
)
That actually has direct relevance to me since the entrance to our Covenant is in a walled garden that has an enchanted device with Range: Room observing it.
A prolate spheroid (capsule) based on the length of the circle. (Length of circle, square of length of circle, something like that.)
I honestly think something like this would be designed during spell creation and set as fact afterward.
Like a circle ward to keep a flame in and stuff for torches would have that info be a lot less vast than something like a warded circle against a demon or something.
In terms of play this would be an added descriptive sentence.
Basically, to me, one spell can have it a sphere and another a cylinder and another it could - with proper size modifiers - go up a mile and another down ten kilometers. It is a judgement call by the designer of the spell, but once set it is always there for that spell.
Honestly, I think the way to make people happy is something similar to the 'instant transportation' mechanics in Transforming Mythic Europe, where they said something along the lines of 'This is how it was designed to work, but your table can interpret it this other way without breaking things'.
1 Like
Here are my proposals for this thread.
First, errata Ring Duration: Ring (p. 112): Modify the first clause to read "until the target of the spell, or part of the target, moves outside the ring".
Second, errata Circle Target: Circle (p. 112): Add the following sentence as the third sentence of the definition. "Note that the circle itself is not inside the circle, and thus not targeted by the spell even if it would be a legal target."
Third, errata in the following insert (on page 113, although it wouldn't actually fit on there — this is a problem to be dealt with later).
Container Targets
Spells with "container" Targets, including Circle, Room, Structure, and Boundary, can work in one of two ways.
First, they can affect any valid target within the Target container at the time of casting, and continue to affect those targets even if they leave the original Target area, for as long as the spell lasts.
Second, they can affect any valid target within the Target container during the spell's period of effect. In this case, a valid target that leaves the container ceases to be affected by the spell, and a valid target that enters (or re-enters) the container is affected, until it leaves or the spell expires.
The way that a particular spell works is fixed when it is designed, and cannot be changed by the casting magus, although a spell working in one way is similar to a spell that is identical apart from working in the other, and so knowledge of one gives a bonus to inventing the other.
For example, a spell to put pink dots on people's foreheads with Target: Room and Duration: Moon could work in two ways. In the version that works in the first way, everyone in the room (on whom the spell Penetrates) at the time of casting gets a pink dot on their forehead, and this pink dot remains on their forehead until the new moon and full moon have both set. In the version that works in the second way, anyone who is inside the room (on whom the spell Penetrates) until the new moon and full moon have both set gets a pink dot on their forehead, even if they were not in the room when the spell was cast. When they leave the room, the pink dot disappears, although it reappears if they go back into the room. These two versions are two different spells, and a maga who wants to cast both (and cannot reliably cast them spontaneously) needs to create two spells.
Finally, make page 113 even more full by errataing in the following:
Circles and Rings in Three Dimensions
The standard Ars Magica rules use an intuitive definition of "inside the circle" for Circle Targets and Ring Durations. A person standing in the centre of a 1 pace diameter circle is inside the circle; someone who happens to be standing directly above it three floors higher is not. If your troupe need something more precise, you can work something out, and it should not break anything in the rules. Bear in mind, however, that it will still come down to the troupe's decision on whether a thing is within the more precisely defined volume.
Comments?
3 Likes
Shouldn't Boundary Targets in Three Dimensions and courtyards targeted with T: Room be handled like Circles and Rings in Three Dimensions?
1 Like
Add:
Similar considerations apply to other container Targets if they are not closed in three dimensions, which is likely to be case for many Boundaries, and may be the case for Rooms or Structures.
3 Likes
There are going to be a bunch of knock on effects from the change to "Container Targets".
This change allows a whole new way of obtaining spells and effects like the Semita Errabunda Fire Guardian (p. 4). If you change the initial effects duration to Sun, with the spell being the second type of container, then that is the only change needed to the original to make it a valid effect. You could shave off a use per day, so the Final level would be 29.
There are others, that one just jumped out at me since we just looked at it and you proposed an errata.