Yes, good point--it will after all still allow species from the other side of the target to pass through.
Scott
I think the Finesse check is for destroying the species in one direction, and destroying all the species emitted by an object is simple. The finesse is for judging the angle to the target to be deceived. Otherwise the default PeIm spell would have a huge finesse target under that rule. The complexity here is the size of the sphere and the fact it is a non-standard shape.
It could easily be a standard shape, say a bubble around the ship. It's meant primarily for hiding the ship from a long distance away, not right up close. If its level could be dropped by making it less useful up close, that'd be okay.
Hmmm. It's not feeling right to me to be able to easily avoid targetting someone for warping purposes and to avoid a finesse roll. My take on it is that there are 3 possible approaches:
- "The black sphere effect - all species that cross the shell get destroyed. This is admittedly avoiding targetting someone and avoiding warping, but has a fairly severe drawback.
- The spell is still cast on the boat, so everything still gets warped (and you probably need a non-standard target based on a shell around a structure), but the species aren't destroyed until they pass a little distance from the boat.
- The shell selectively destroys species that pass through it - this feels like it should require a finesse roll.
Well, even if the warping stays, there's one thing to remember. The spell was designed for the river boat, a couple dinghies, and the crew that came over from England. So even if it is a high enough level spell to Warp, there would be one large boat, a couple smaller boats, and a small group of grogs that wouldn't be Warped by it.
How do you rationalise the Invisibility from the core rules with these options?
I do not think the black sphere makes any sense at all. The the core rules version would then create a black blob, not an invisible person.
It's a structure target, so can see it being designed for one of the boats, but not all of them.
The invisibility from the core rules book only destroys the species emitted by the target, not the species coming from behind it (i.e. a variant of option 2 without the fancy target). Under the black sphere option, you're destroying both.
(There is a bit of a problem with light passing through the target to carry the species from behind the target, which the core rules tries to get around by saying you still cast a shadow - this doesn't quite work, but the problem here is that invisibility under the core rules doesn't quite work if you look at it hard enough rather than what we're trying to do now, and it's a independant problem from the black sphere, which is species rather than light.)
I think I see your point but I also think that the more complex target modifier covers that complication. The idea is that the species within the shell are stopped from crossing the shell boundary. Species originating from outside the shell are not affected. Species within the shell are not affected.
We're discussing the metaphysics of an imaginary magic system, which is ok, but we should come back to basics.
I believe the effect as outlined is reasonable as it fits within the themes already in raw, it is not over powered, and facilitates fun. It's also not an unreasonably low level power which could be exploited in other ways.
Sometimes there is a propensity to add Mags to effects because they are outside the official rules (I'm very guilty of this too), and I'm trying to challenge that behaviour because the magic system is based on innovation and invention.
Hmm. I think that the non-standard target modifier shouldn't in itself cover it (there are enough benefits from the group actually within the invisibility sphere being able to see each other). You could possible argue that additional magnitudes for complexity should cover it, particular as the spell doesn't allow any flexibility in which species are destroyed - it's always all of the ones in the sphere. I still think that this would be essentially substituting additional magnitudes for finesse rather than finesse never being needed in the first place, which isn't explicitly allowed in the RAW, but is arguably implicit in things like Conjuring the Mystic Tower.
Basically, I think we're getting into House Rule territory, so it's up to MTKnife to make a final call on what he wants to allow - either way's probably reasonable.
Greetings all,
I'm reaching out because MTKnife said it would be okay if I jump into the campaign and I wanted to introduce myself. I've read the covenant background and current magi roster, but don't know anything about your earlier adventures, so it will be interesting to learn about them in-character.
I'll be posting character sheets in the appropriate threads in the next day or two, along with a handful of custom spells.
I look forward to playing with you all!
Also, I should note that the forums have me in a probationary period as I'm new. They're approving individual posts, so it may take time to get them up.
Welcome!
Yes, welcome.
Thank you for the warm welcome! I just posted my two sheets and am happy to get input/discuss.
Reading the "Chronology" thread would help get you up to speed, though of course your characters will still have to learn about the situation for themselves. 
Scott
Thank you! I have read it now. I had been trying to piece that together by reading the actual stories!
Happy Christmas everyone!
Merry Christmas!
Scott
Merry Christmas all! finally getting time to read the forums too - ain't holidays grand.
As another suggestion, maybe creating faerie birds (Muto Animal) to do scouting for us?