D&D 5E Wall of Force options

[Paul Farquhar]

I was about to ask if a hemispherical wall of force had a floor, wondering if something could go under it, but then I remembered Crawford's "ruling" about tiny hut.

It doesn't have a floor, but I'm pretty sure solid ground counts as total cover.

What follows of, course, is "what about Earthquake?" If you go by the way @Clint_L rules, a Wall of Force should block the effect of the Earthquake spell, even though that makes no sense. But then, so would a brick wall.

Of course, the rules are actually far from clear if total cover can block the effects of an area spell, or just the positioning of the point of origin.

 

[Paul Farquhar]

I'm not sure what you think is so special about moonbeam.

Nothing particularly. Most of it goes for other spells like Ice Storm, that are cylinders, directing the effect downwards. Firstly, if Sacred Flame ignores total cover because "the effect comes from above", then the same should be true for any spell effect that comes from above. They must have forgotten to mention it in the spell descriptions. Of course, it's probably more sensible to say that they ignore total cover between the caster and the target, but are affected by total cover above the target. In which case, a dome Wall of Force should block Moonbeam, Ice Storm and Sacred Flame, but a simple wall blocks none of them.

Secondly, the point of origin for cylinders is not on the ground. In the case of Moonbeam, it's 20 feet above the ground. So long as the point 20 feet in the air isn't behind total cover you can target the spell effect there. Note: beware low ceilings!

 

[James Gasik]

It doesn't have a floor, but I'm pretty sure solid ground counts as total cover.

What follows of, course, is "what about Earthquake?" If you go by the way @Clint_L rules, a Wall of Force should block the effect of the Earthquake spell, even though that makes no sense. But then, so would a brick wall.

Of course, the rules are actually far from clear if total cover can block the effects of an area spell, or just the positioning of the point of origin.

I was thinking about Erupting Earth, actually.* Also, could a brick wall really block Earthquake? It tends to destroy them with the "Structures" bullet point, right?

*basically wondering if targeting a square outside the Wall would still cause the earth to erupt on the other side of it. "Choose a point you can see on the ground within range. A fountain of churned earth and stone erupts in a 20-foot cube centered on that point."

As for the "floor", like I said, I didn't think Tiny Hut would have one either (a hemisphere only has one if it's solid, my thinking is that it's like a hollow glass sphere cut in half), but Crawford says it does, so...

 

[Paul Farquhar]

Also, could a brick wall really block Earthquake? It tends to destroy them with the "Structures" bullet point, right?

RAW, in theory. The effect radiates out until it hits total cover, then stops (as per @Clint_L interpretation). The wall takes damage and may fall down, but there is no rules for the spell effect continuing on if the total cover is removed (and whose to say the rubble isn't total cover in any case). Of course, this is where any sensible DM would rule that the effect is transmitted through the ground, so the only "total cover" would be a void.

One might houserule "if effect X can travel through material Y, then Y does not provide cover". Using this rule, one might say X = Psychic damage, and Y = force effects, if one wanted to allow psychic damage spells to be useable through a Wall of Force.

 

[James Gasik]

RAW, in theory. The effect radiates out until it hits total cover, then stops (as per @Clint_L interpretation). The wall takes damage and may fall down, but there is no rules for the spell effect continuing on if the total cover is removed (and whose to say the rubble isn't total cover in any case). Of course, this is where any sensible DM would rule that the effect is transmitted through the ground, so the only "total cover" would be a void.

One might houserule "if effect X can travel through material Y, then Y does not provide cover". Using this rule, one might say X = Psychic damage, and Y = force effects, if one wanted to allow psychic damage spells to be useable through a Wall of Force.

So thinking about this, I notice that the rules for cover say:

A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.

When, exactly, does the italicized section apply? (my guess is that this is talking about AoE's that would extend around cover, but I'm not 100% on that)

As for your proposed house rule, that seems logical. If there is a glass wall between you and a target, a giant ape probably could still hit you with a 7d6 boulder!

 

[Paul Farquhar]

When, exactly, does the italicized section apply?

Good question! The text in the description of Fireball says "The fire spreads around corners" but most spells don't indicate what they are blocked by. The text for Wall of Force says "Nothing can physically pass through the wall" which implies anything that isn't physical (such as Moonbeam) can pass through it.

I assume @Clint_L would take "some spells" to mean "when specifically mentioned in the spell description" which I think is none.

 

[James Gasik]

Good question! The text in the description of Fireball says "The fire spreads around corners" but most spells don't indicate what they are blocked by. The text for Wall of Force says "Nothing can physically pass through the wall" which implies anything that isn't physical (such as Moonbeam) can pass through it.

I assume @Clint_L would take "some spells" to mean "when specifically mentioned in the spell description" which I think is none.

So, just to clarify, a spell effect that goes under a Wall of Force could theoretically affect someone behind one, just as a spell effect that goes around one could?

I get that spells are largely written as if they resolve on a flat, 2D plane (barring oddities like cylinders), so this is probably a huge grey area at the moment- I know I've had some DM's give me funny looks when I use cone effects in 3 dimensions, and they've claimed that they don't believe that's the intent of the spell, though they are similarly baffled by the constant use of three dimensional spell effects (cones, spheres, and cylinders) in a game that has historically been very bad at dealing with the third dimension.

 

[Paul Farquhar]

So, just to clarify, a spell effect that goes under a Wall of Force could theoretically affect someone behind one, just as a spell effect that goes around one could?

DM's call. I wouldn't assume your DM would automatically rule that way, since I don't think any spell descriptions explicitly state either effect. In terms of gameplay fun, I think it's better to give benefit of the doubt against the Wall of Force.

If you have ever played Solasta, that makes quite a good job of mapping 3D spell effects to a grid.

 

[Samloyal23]

So, if you made a version you could launch spells through from one direction, so you could fire out of a dome covering you, what level would it have to be maintain balance? 6? 7? 8?

 

[MNblockhead]

So, if you made a version you could launch spells through from one direction, so you could fire out of a dome covering you, what level would it have to be maintain balance? 6? 7? 8?

Well Cube of Force allows for this and other options, and it is only rare. According to the DMG, rare items should be rewarded to PCs that are at least 5th level.

Wall of Force is a 5th-level spell, so you have to be 7th 9th level to cast it. (Corrected)

I don't know how to reconcile these two items of information. Cube of Force should should have a higher rarity than "rare".