Private message exchanges do not result as "official stance" without authorization. This is not an issue of law, but of procedure and etiquette. And yes, you can lose your professional standing - that is: your job - by disregarding it.
You infer far too much from changes in errata on a peripheral matter: a digit from stats for an effect in a complex item.
Not quite. Atlas and David changed the digit, conceding that point to you. But we also read here and here on the forum:
In other words: you think David answered that question in that private message exchange, while he does not.
So in that private exchange was a misunderstanding, how it applied to the working of ArM5 p.99 Constant Effect Devices. This happens all the time in talks and message exchanges.
But as it was you, who made part of that exchange public on this forum as "official stance" on that topic, you alone are responsible for not having detected and clarified that misunderstanding before.
And yet quite nearly the opposite position was held after the fact. I'll trust their opinions on how they feel over what you say about their opinions.
No, they didn't concede that point. I submitted new errata explaining how the new position differed from the old and so now required a change. My new submission was accepted. So if you're saying the change happening is conceding a point, it sounds like you're telling me they conceded the point that the position changed. Yes, I have a pretty good idea what's gone on with the errata seeing as I've submitted something like 50% of the items listed.
But as long as you read "is not actually cast twice a day" as "is cast twice a day," completely ignoring "not" while I don't to say I read it wrong, I guess there is no way to convince you with logic.
That was related to but now quite my worry. Rather, it was multiple different triggers. You put on the ring of invisibility at 4:00 in the afternoon and... nothing. Too bad. You have to be wearing it at sunset or sunrise for it to turn on. You can turn it off whenever you want, though, as taking it off is the ending trigger.
I do see a simpler way around this than I posted earlier, assuming the group doesn't say there is flicker with D: Concentration. I used Moon above to avoid this issue so there would be no question of validity. Anyway, make the effect with unlimited uses, D: Concentration, and have the item maintain it. Make a second effect as well, ReVi triggered at sunrise/sunset to trigger the first effect on the wearer.
But I suppose there is also still the question of whether or not there is a period of time when the item cannot concentrate or if it's but a moment. If the lack of ability to concentrate lasts any longer than that brief moment, then using the environmental trigger with maintained D: Concentration is doomed to failure, or at least flicker.
I am interested in this topic, because I am designing an item which creates a physical object as long as the item is active. i.e. the effect starts and stops when the user wishes. I am also a little concerned about sunrise/sunset because I don't want my item to disappear, then reappear.
As my magus doesn't have tethered magic, the effect would need to be duration Concentration, so it can be ended at will. However, the sunrise/sunset part causes a problem for me. If the item can maintain the concentration and/or trigger a new instance when needed at sunrise/sunset without the object flickering, this is great. If it does flicker, I need to rethink the project.
Just to clarify, although my item has multiple uses, it can only create and maintain 1 object at a time It cannot create another one whilst there is one already there.
Which doesn't exactly make your previously claimed "official stance" without authorization any more "official", right?
We had that already here. The "not actually cast twice per day" used by unverified David Chart here is a colloquialism used in a private message exchange. It tells you in a friendly way, that a persisting constant effect (from ArM5 p.99 box), namely HP p.101 The Rising of the King, remains over sunrise and sunset controlled by the ghost via HP p.97f Passing the Reins of Corpus.
It does not even address the number of castings needed per day in ArM5 p.99 box, or other conclusions of Constant Effect Devices which you are so eager to draw. You still haven't got it in context - showing thereby, why your claimed "official stance" was in serious need of checking by David before you made it.
Here's an odd twist. Can you have two triggers? (Paying the +3 cost twice, of course). Say you had an invisibility ring with concentration duration, unlimited uses, the trigger "when put on," and the trigger "sunrise/sunset." Would that be legit? Then it could be triggered by putting it on or when concentration gave out at sunrise/sunset.
I'm not aware of any part of the rules that says you can't have two triggers.
Of course, this still leaves open the question of flicker at sunrise/sunset, which was the main question of this thread.
Standard ArM5 p.98 Triggers can be arbitrarily complex and do not add to the level of effect.
But mixing two or more of standard Triggers, Environmental Triggers and Linked Triggers AFAICS would require a troupe decision. And for Constant Effect Devices sans flicker you would need Environmental Triggers or Triggers linked to other effects with Environmental Triggers.
Without such a troupe decision, you could have the ring of invisibility (Standard Trigger by putting it on, D: Concentration, mantains Concentration, unlimited uses or a little less) come with another simple effect (Environmental Trigger at sunrise/sunset, D: Momentary - that is two seconds or so, 2 uses/day) that just makes the ring vibrate. Thereby the wearer knows he needs to concentrate - and voila, no flicker noted by anybody else. Of course, this might delay putting the Parma Magica on by a fraction of a second: but the ring's vibrations also tell the wearer when that is about to expire.
I'm still having trouble reconciling all of that complexity with the statement on p. 99 of the core rules that the concentration effect (presumably with the device maintaining concentration) "is useful for things like invisibility rings, which have their effect when put on, and then maintain concentration and invisibility until removed." That sentence seems to imply that using concentration duration in an item would allow for an item that simply maintained concentration until a triggering event occurred (such as removing the ring), regardless of an intervening sunrise or sunset. The sentence doesn't say that a concentration duration invisibility ring would have its effect when put on, and then maintain concentration and invisibility until removed or until sunrise or sunset, whichever comes first.
It's still a muddle for me. And that's quite apart from the flicker issue.
A simple approach to the flickering Ring of Invisibility problem is to allow a device to be created with a Target of "Wearer of the Ring" at the same level as Touch, with the Sun/pseudo-constant Duration.
As per AM5 pg. 114
The alternatives of multiple triggers and or Perdo to end the spell are too complicated for players and lead to excessively high level enchantments for simple effects, IMO.
Another approach is to create an item with Unlimited uses of a R:Touch, D:Mom effect. We know that D:Mom can encompass a whole round, and in particular that a D:Mom spell/effect can affect a spell/effect cast in the following round, so the invocations should overlap enough that there's no flicker.
Note that nowhere in the corebook there's a case mentioned with "flicker". The only mention of flicker is made in the case of "consecutive" D:Sun effects, to mention that there is no flicker, just in case one wondered if there might be. I find it remarkable that a comment that, as I read it, was meant to convey the idea "don't worry about flicker [because it would make things ugly]" ended up having people worry about flicker!
If, when describing constant effects, you have to stipulate that there isn't flicker, it's strongly suggestive that other effects do flicker as they expire and need to be recast, whether that happens based on a trigger or not. Note, saying an effect flickers isn't requierd by the core book, but is instead a consequence of the rules. When an effect expires, it needs to be recast. There is a momentary gap in time where the effect isn't in place, while it is being recast. Constant devices never have that problem...
What about devices that have a concentration duration (like the invisibility ring of the example on p. 99 of the core rules)? It doesn't seem to describe them as stopping and being recast. Rather the rules say that they "start to wear off" at sunrise and sunset and require a moment of concentration to "perpetuate" the effect? The use of the phrase "start to wear off" rather than "wear off" and the use of "perpetuate" rather than something like "renew" or "recast" makes me question whether these effects are supposed to stop and start again or whether they are maintained with simple concentration. Again, I look to the following sentence, which states that this effect "is useful for things like invisibility rings, which have their effect when put on, and then maintain concentration and invisibility until removed," and I wonder whether flicker is inevitable in that case.
Or is this just another case for the Limit of Flicker?
My interpretation is that if a person holds concentration on the effect from just before sunrise/sunset to just after and then lets the item pick it back up, there is no flicker because it never ended. But you can only do this for so many effects at once, and it's unlikely you can do this while renewing your Parma Magica. So for me avoiding flicker is about wanting to have a non-constant effect that you don't want to concentrate on yourself.
I disagree. In general, if someone state "A is true" in a context where the truth of A is particularly relevant, there is absolutely no implication that A will be false in other circumstances. In the context of enchanted devices, a constant effect is obtained as a juxtaposition of "consecutive" D:Sun effects. The book simply points out that a D:Sun effect can be produced sufficiently soon that there is no gap between it and the previous one, which is definitely relevant if you want the seamless result of a constant effect.
There is nothing of the sort in the rules. You seem to be assuming that an effect can be recast only after it expires. But it need not be the case. One can start recasting the effect while the previous effect is still in place. It all depends on how long is D:Sun, really. The way I see it, D:Sun "The spell lasts until the sun next rises or sets" means that if the sun is currently rising or setting, the effect lasts until the end of the next sunrise/sunset. If you assume a sunrise/sunset lasts approximately a Diameter (the time interval when the Sun is partially above and partially below the horizon) that gives you a Diameter of slack. Note that this is not limited to D:Sun. In general, to me it seems strongly implied by the setting (though I wish it were spelled out more clearly, as it was in previous editions) that, if an effect lasts e.g. "a year", you can time a single casting every year so that, year after year, there's no gap.
Once again, one is free to read stuff as one wants, but it seems to me that a lot of Ars Magica players make things appear far more complicated than they ought to be, and than they really are!
Your definition also ignores the other discussion of constant effects, though, and suggests that they can be started and stopped. This doesn't appear to be the case.
Let me just say that, by implication, you've proven my point. If one must concentrate to maintain the effect of item item through the sunrise/sunset, it will end at sunrise or sunset without that intervention. If the item has an environmental trigger of sunrise/sunset, and one cannot maintain concentration on the item's effect (either due to design or incapacity) the effect will flicker off, and then back on. Concentration of the user is external to and independent from the device.
A diameter of slack, if you will, is an even more significant period of time, about 2 minutes, or 20 rounds. As to the definitions of sunrise, and sunset, it seems entirely consistent to say that the sun has risen once the disc begins moving above the horizon, and sunset is when the entire disk is below the horizon. I suppose this does make the "day" about 4 minutes longer than a night, but I hardly find that to be of importance. You're essentially creating a 2 minute gray area, twice a day, where the sun is neither risen or set. I might begin casting a spell before the sun has risen, to have it take effect at the moment I see the first ray of light cross the horizon, effectively holding the spell until then, but it is not cast until the sun is risen. Likewise, I might begin casting a spell as the sun is setting, but I dare not release it until the sun has actually, fully set, that is the entire disk has fallen beyond the horizon. These may be somewhat modern definitions of what sunrise or sunset is (it's what the USNO uses), but having a two minute gray area around the sunrise/sunset period seems needlessly complicated in setting I imagine to be a real world, and in the actual game itself, will never really come into play, nor does it actually affect whether an item "flickers" when the effect expires and is recast...
I wonder how much value people give to "a few moments" being written instead of "a moment" with regard to D: Concentration and sunrise/sunset. That could easily be taken to mean that there must be a slight gap as Momentary is only one round, not a few rounds.