Protection from spell: Duration 0

[temnix]

I'm making some traps that are likely to be set all in a heap, on the same spot. When an enemy triggers them, he is going to get hit by the whole batch. But I had to increase the frequency of the trap AOE to compensate for its very small radius, and now it's sometimes too quick. Before the trap can cancel itself, it hits twice on occasion. I don't want to sacrifice frequency, and for this reason I need some way to make sure every trap's spell only hits once. The problem is that whether I put there an immunity to the projectile or an immunity to the spell itself, I must give it some duration, a couple of ticks, at least. But with all these traps in a bundle and using "None" projectile (or even anything else that quick) I know I would sometimes block the effects of subsequent traps. I remembered how some spells in the games use a Protection effect, against something, with duration 0, and I've used that too once or twice. I would like to know just how that works. Does Instant/Limited at Duration 0 mean protection during this execution of the spell, without occupying any real time? That would be ideal for keeping the traps separate, effective and repetition-free.

[Bartimaeus]

A duration 0 opcode 206 (Protection from Spell) that specifies the same spell that's being used will protect against all subsequent effects for that specific cast. i.e. if SPWI107's (Friends) first effect was a 206 that specified itself with duration 0, none of the other effects of Friends would be applied. This is true even if some of the other effects are delayed: they will still fail. If instead the 206 is the very last effect, then all of the other effects would still apply. So the order of the effects is critical for self-immunizing 206s.

I was curious about the other point you asked, whether a duration 0 206 would occupy any real-time that would make it potentially protect against anything but the spell applying it. I didn't think it would, but I decided to be empirical and test it where I would have 1 mage cast a spell that protected against another spell with a duration of 0 while 5 other mages cast the protected-against spell all with the same casting time and from the same distance (i.e. point blank) on the same creature, I was surprised to see that it actually did finally protect against it after about 5 or 6 runs of trying that (so about 25 or 30 casts where all of them were cast at the same time). So it is possible but seemingly very unlikely - for practical purposes, I think you should consider a 0 duration 206 to only protect against the same spell casting it. Would have to be ve-ery rapidly applying that same spell over and over for that to come into play.

Edited June 17, 2021 by Bartimaeus

[temnix]

Good answer. Thanks. You should also test how well this protects against projectiles, with effect 83. That was my original question. I know about the order of effects with protections; for that matter, I even know that 318 is "faster" than 206 and can sometimes stop effects below it, too. In this case, when several traps would likely go off at once, I wanted to put some kind of block early on in the effects stack, so I chose Immunity to projectile. I'll go on the assumption that duration 0 also lasts only to the end of the current spell application.

Edited June 17, 2021 by temnix