@JeremyECrawford Is a glass window considered a total cover for the purpose of targeting a creature with Hold Person spell?
— Draconis (@DerynDraconis) November 28, 2016
A solid obstacle, regardless of material, can provide total cover. A closed window counts. #DnD https://t.co/1gIlswOaSa
— Jeremy Crawford (@JeremyECrawford) November 29, 2016
@NTMTOPodcastThat’s a good interpretation of rules as written – but is it really how you’d rule as a DM for this spell? Yep.
— Jeremy Crawford (@JeremyECrawford) November 30, 2016
@NTMTOPodcastInteresting… do you rationalize that in game? ie. Fireball actually projects a ball of fire. Same thing with hold person? The first sentence of fireball says you literally shoot the magic out of your outstretched finger.
— Jeremy Crawford (@JeremyECrawford) November 30, 2016
In previous editions, there was a concept called “Line of Effect” – basically a clear, unobstructed path for the magic of the spell to follow to reach its target.
If you were casing Hold Person on someone, you had to have Line of Sight (had to be able to see them) and you also needed to have Line of Effect (the magic needed to not have to pass through solid objects to reach the target). A window gives you the former, but not the latter.
Now, there were cases where Line of Effect didn’t apply. If you cast Catapult, for example, and hurled a brick at someone’s head, the magic isn’t what is going through the window to affect the target – the brick is, and it shatters the window. All the magic does is throw the brick.
That said, if the brick you were trying to throw was on the other side of a window, then Catapult wouldn’t work, because the magic wouldn’t be able to reach it without passing through a solid object, even though you can see the brick.
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Cover is always something the DM will have to judge on the fly, because that’s how cover works in real life.
A typical window is cover against a small rubber bouncy ball, which will just bounce harmlessly off it, but the same window is NOT cover against a sling bullet or a crossbow bolt. Maybe a particularly sturdy window could be, or one designed to be “bulletproof” via either mundane or magical means, but that’s different.
Also, you might be surprised the sorts of things that will penetrate certain kinds of cover. For example, it’s a well established fact that modern military sandbags used to stop bullets are easily defeated by arrows shot from bows, which just punch through easily because they’re much heavier projectiles that bullets, with much more momentum, and their power comes from their weight not their speed.
Why is “Clear Path” interpreted to mean Straight Path? I can throw a ball over a wall, and along that Curved Path is also a Clear Path. A soldier can throw a grenade over a wall, same deal. Why would a fantasy games magical spell named Fire “ball” be restricted to traveling in a Straight Path? Boomerangs, MLB Pitchers, Bocce ball thows, even an NFL quarterback tossing a hail Mary, none of these things follow straight paths… why would a Fireball?
Firebolt… I’d say that would need a Straight and Clear Path…