Mistwell said:
How is getting BETWEEN two actively moving, fighting people easier than getting in a fixed arrow slit that is not moving?
Well, if we again look at the 3E rules (which took a slightly less arbitrary approach to cover and arrow slits, when the fireball text was originally written), let's try shooting an arrow at a target on the other side of two actively moving, fighting people, and then at one on the other side of a fixed arrow slit that is not moving.
Bonus to target's AC in case 1: +4.
Bonus to target's AC in case 2: +10.
It looks like, when the text about fitting the fireball through an arrow slit was originally written, it was certainly considered to be easier to get between two actively moving, fighting people easier than getting in a fixed arrow slit that is not moving.
Is it your opinion that the bead travels in in a zig-zagging, curving, automatic path to it's destination (like Magic Missle) as long as it doesn't pass through specifically an arrow-slit sized path?
If that's what it needs to do, sure.
By 'specifically', I'd read instead 'or equivalent', but I don't consider half cover to be equivalently narrow to 9/10 cover.
Let's say I can see a person on the other side of a glass door. I can't cast Charm Person on him - I don't have line of effect.
Now let's say there's a 1' square cat door in the bottom corner of the door. Drawing a straight line from me to the person still goes through the glass. But the one foot hole in the door means that the glass doesn't block line of effect - even though it's down in the corner.
Now, instead of Charm Person, I want to cast a Fireball to burst over the person's head. The spell has line of effect, but the bead has to pass through a narrow passage - the cat door - to get there. If I can make a ranged touch attack on the cat door, I can pass the bead through the gap - but I don't see anything prohibiting the curved path, down from my finger, through the cat door, then up above the person's head, as long as I make that touch attack roll successfully. I've got line of effect to the place I want the spell to originate, and I hit the gap with my RTA.
Now let's swap the glass door for two guys fighting each other. There's now so much empty space between me and the point of origin that no RTA is necessary - I'm no longer passing the bead through a narrow passage.
-Hyp.