D&D General "that you can see", "line of sight", glass, mirrors, ~clairvoyance, blindsight, and anything else.

[Oofta]

I was prompted to raise this topic when after watching a play stream where one of the characters was glued to the front of a vehicle and, as the character's head then couldn't turn sufficiently, there was no ability to cast healing word on passengers behind.
If a mirror was used to see the passengers, would the "A Clear Path to the Target" requirement be satisfied?

Does the caster have line of effect? My test that question is simple: if they were shooting an arrow in a straight line could they have hit the target without breaking something in between*? Next, in the case of healing word it has the additional limitation of "that you can see".

I'd allow "that you can see" to be covered by the mirror. The windshield, if there is one, on the other hand could block the line of effect.

*That can get a bit tricky, in general though the arrow rule still applies. An arrow would penetrate, say a sheet you were hiding under if you were silly enough to think that would work. If you were totally concealed behind a tower shield it would not.

 

[Paul Farquhar]

So are people who live in glass houses, immune to spell effects.

Does glass provide total cover?

Does it provide total cover against a sniper rifle?

What if it's made from bullet-proof glass?

It's up to the DM to decide if something provides cover, and that is going to depend on what you are attacking with. Which is why we have human DMs to make the judgment call.

 

[greg kaye]

Does glass provide total cover?

Not against an effect that, during transit, would shatter the glass.
Against spells like healing word and heat metal, 'apparently'.

 

[ad_hoc]

Does the caster have line of effect? My test that question is simple: if they were shooting an arrow in a straight line could they have hit the target without breaking something in between*? Next, in the case of healing word it has the additional limitation of "that you can see".

I'd allow "that you can see" to be covered by the mirror. The windshield, if there is one, on the other hand could block the line of effect.

*That can get a bit tricky, in general though the arrow rule still applies. An arrow would penetrate, say a sheet you were hiding under if you were silly enough to think that would work. If you were totally concealed behind a tower shield it would not.

Yeah, my test would be something like if they can point to it (unless verbal only) and see it in some form then that's good enough for me.

 

[Lanefan]

Does the caster have line of effect? My test that question is simple: if they were shooting an arrow in a straight line could they have hit the target without breaking something in between*? Next, in the case of healing word it has the additional limitation of "that you can see".

I'd allow "that you can see" to be covered by the mirror. The windshield, if there is one, on the other hand could block the line of effect.

This is the part that doesn't make sense to me: if - as part of the spell - there's nothing physically travelling from the caster to the target point for the glass to block, and you can see the target point through the glass, then why can't you target that point?

(never mind that I'd have it that Healing Word - or any other sound-based spell e.g. Command - wouldn't work if the target couldn't hear it, which would be more relevant in the car example: sound can't get through the glass)

*That can get a bit tricky, in general though the arrow rule still applies. An arrow would penetrate, say a sheet you were hiding under if you were silly enough to think that would work. If you were totally concealed behind a tower shield it would not.

Personally, I don't mind if certain spells can be fired "blind" into areas the caster can't see; with an aiming roll required to put it in the desired place. Sleep and Dispel Magic are two such. But 5e seems to have done away with such, sadly.

 

[Greenstone.Walker]

…much like you wanted to shoot an arrow rather than cast a spell.

That's how I rule it. If something between you and the target would block an arrow, it blocks a spell. Magic attacks involve something physically travelling from caster to target.
Pane of glass? Blocks a spell. Sheet of rice paper? Doesn't block a spell.

I prefer to use the word "block" instead of the word the rulebooks use, "conceal", because there are things that can conceal you without blocking an attack (for example, a sheet of black paper).

 

[Oofta]

This is the part that doesn't make sense to me: if - as part of the spell - there's nothing physically travelling from the caster to the target point for the glass to block, and you can see the target point through the glass, then why can't you target that point?

(never mind that I'd have it that Healing Word - or any other sound-based spell e.g. Command - wouldn't work if the target couldn't hear it, which would be more relevant in the car example: sound can't get through the glass)

Personally, I don't mind if certain spells can be fired "blind" into areas the caster can't see; with an aiming roll required to put it in the desired place. Sleep and Dispel Magic are two such. But 5e seems to have done away with such, sadly.

Sleep is just an area you choose within range so it works just fine in darkness. As would, say fireball.

Dispel magic is a bit different (and overall less powerful than it used to be) and it specifies "Choose one creature, object, or magical effect within range." It doesn't specify that you have to see the target, but it's still a bit up to the DM on whether you can choose something you can't see. I'd allow it in a lot of cases.

The whole line of effect thing was added/clarified in 3, it's not new to 5E.

 

[Lanefan]

That's how I rule it. If something between you and the target would block an arrow, it blocks a spell. Magic attacks involve something physically travelling from caster to target.

What, though?

With Fireball, it's obvious: a little rolled up ball of bat guano. Magic Missile also, the force missile fires from caster to target. Acid Arrow, same thing - in this case, an arrow.

But with Hold Person? With Charm Monster? With Dispel Magic? With Lightning Bolt when its start point is remote from the caster? What physically goes from the caster to the target (or the start point, for LB) with spells like this?

The answer, of course, is nothing.

So why should - and how can - a pane of glass block these spells?

 

[Lanefan]

Sleep is just an area you choose within range so it works just fine in darkness. As would, say fireball.

Dispel magic is a bit different (and overall less powerful than it used to be) and it specifies "Choose one creature, object, or magical effect within range." It doesn't specify that you have to see the target, but it's still a bit up to the DM on whether you can choose something you can't see. I'd allow it in a lot of cases.

Yep, Dispel got both nerfed and made "safer" over time, as when it was area-effect you could easily hit things you didn't want to hit. I far prefer the higher-risk higher-reward version.

The whole line of effect thing was added/clarified in 3, it's not new to 5E.

3e clarified in with regards to darkness, fog, or other visual obstruction that wouldn't otherwise physically block the spell; and got it right. I don't recall it going into detail about the can't-cast-through-glass bit, though.

And I'm pretty sure 3e still had some spells you could shoot blind e.g. behind a door or wall.

 

[Paul Farquhar]

Not against an effect that, during transit, would shatter the glass.
Against spells like healing word and heat metal, 'apparently'.

Maybe. The rules are actually very vague:

Cover​

Walls, trees, creatures, and other obstacles can provide cover during combat, making a target more difficult to harm. A target can benefit from cover only when an attack or other effect originates on the opposite side of the cover.

Note, the use of the word "can", which indicates uncertainty, and the absence of the word "glass" from the list of things that can provide cover. Is glass an obstacle? Only the DM knows.