Can spells be cast through a Wall of Force?

Question

The spell description of wall of force is silent on the question of whether spell effects can pass through the wall. The semi-relevant part of the description states:

Nothing can physically pass through the wall. It is immune to all damage and can't be dispelled by dispel magic. A disintegrate spell destroys the wall instantly, however. The wall also extends into the Ethereal Plane, blocking ethereal travel through the wall.

How are folks ruling on the question of spells passing through the wall (in both directions)? If the answer is that spells cannot pass through the wall, do you rule that it also blocks line of effect (so that you can't target a spell on the other side)?

Answer 1

Mike Mearls’ unofficial ruling is that Wall of Force does block spells, including lines of effect

Quoting Mike Mearls on Twitter:

Aug 28Jim Miller ‏@pokereleran@mikemearls Is there a line of effect in D&D and does Wall of Force block it?

Mike Mearls – ‏@mikemearls@pokereleran in general, a barrier that stops physical objects stops spells

Rulings from developers on Twitter are in no way considered official rulings, but this is still a ruling from someone who knows the game supremely well.

Answer 2

A wall of force blocks magic by granting total cover.

Although this is an old question, I discovered a relevant ruling while researching another question, and would like to add it here for completeness.

D&D 5e designer Jeremy Crawford, in an unofficial ruling, confirms in a tweet that wall of force provides total cover:

Q: could a wizard make a sphere around a creature using wall of force and then chill touch to damage them through the wall?

Crawford: Unless a spell says otherwise, you can't target someone behind total cover (PH, 204)

Also here, in specific reference to wall of force:

Q: Wall of Force is invisible...so it doesn't provide cover does it?

Crawford: Cover is a physical obstruction, not necessarily a visual one.

The reason wall of force blocks spells is that it, as an obstacle, it provides total cover to anyone fully behind it as per PHB p.196:

A target has total cover if it is completely concealed by an obstacle.

Crawford's unofficial ruling confirms that "concealed" here is a synonym for "covered", not "invisible" as it meant in earlier editions of the game. And, as per PHB p.204, this prevents a caster from targeting you:

To target something, you must have a clear path to it, so it can't be behind total cover.

Answer 3

Nothing being able to pass through the wall makes it count as total cover, and that makes targets on the other side of it invalid spell targets. From "Targets" in the PHB's Spellcasting chapter, page 204:

To target something, you must have a clear path to it, so it can't be behind total cover.

Answer 4

There are three potential interpretations in play here:

• One interpretation is that visual concealment is necessary for total cover, leaving targets on the other side of a wall of force, or a mundane transparency such as a floor-to-ceiling windowpane for that matter, fully targetable by spells and spell effects, or even mundane attacks (albeit with no guarantee of success).
• Another interpretation is that even a transparent surface grants total cover, as it is a physical obstacle, albeit one unable to actually conceal a target.
• The middle-of-the-road path is that spells can be targeted based on line of sight (including through magical and mundane transparent walls and surfaces).
  • Spell effects with physical components (fireballs, rays and such) behave like mundane projectiles and cannot pass through a transparent surface of any sort as a result, or are restricted in how they can pass through them.
  • Spells whose effects are immaterial (such as a mind-altering dominate spell) can freely traverse something transparent.

The applicable RAW is as follows (PHB p. 204):

A Clear Path To the Target

To target something, you must have a clear path to it, so it can't be behind total cover.

and (under Areas of Effect)

A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9.

Going to p. 196 of Chapter 9 of the PHB where total cover is defined:

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.

Wall of force (p. 285) does not grant any concealment:

An invisible wall of force springs into existence at a point you choose within range. ...

However, since it is a barrier:

Nothing can physically pass through the wall.

it clearly meets the definition of obstacle, leading us off the end of the RAW, and into RAI territory.

Answer 5

Spells may or may not be cast through a Wall of Force. It depends on the spell.

A spell effect that physically must travel from the caster to the target cannot be targeted at something on the other side of a Wall of Force.

"A Clear Path to the Target. To target something, you must have a clear path to it, so it can't be behind total cover."

Since the Wall of Force is an obstacle that provides cover for physical elements as per its description "Nothing can physically pass through the wall", it is a physical obstruction, as Jeremy Crawford and Mike Mearls have addressed in their tweets, spell effects that must physically travel from the caster to a target cannot target something behind a Wall of Force. Examples: a Firebolt Cantrip, Magic Missile spell, Scorching Ray spell, Lightning Bolt spell.

A spell that its effect starts at a point you can see within range can be cast on the other side of a Wall of Force.

The rules of targeting for not being able to place an area of effect have two additional requirements that have not been taken into account in previous answers at the time of my answer:

"A Clear Path to the Target. To target something, you must have a clear path to it, so it can't be behind total cover. If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction."

For you to not being able to place an area of effect on a point that you indicate:

1. You should not be able to see the point you want the origin to be ("a point you can't see"), and

2. "an obstruction, such as a wall, is between you and that point"

These two have to be met in order for you to not be able to place a point of origin in a place that you want due to the "and" operator in the rule "a point that you can't see and an obstruction, such as a wall, is between you and that point.

In the case of a Wall of Force, as per the spell description, it is invisible ("An invisible⁠ wall of force springs into existence..."), so you can see through it. Since you can see through it, if a point of origin you indicate for a spell lies on the other side of a Wall of Force from where you are casting the spell, you can see that point. As you can see that point, the first requirement for not being able to target a selected point of origin is not met.

The Wall of Force is indeed a physical obstruction between you, the caster, and the point of origin you select (as discussed before), and that would meet the second requirement of an obstruction being between you and the point you select.

Since both requirements must be met for you to not be able to cast a spell at a point of origin you select (hence the "and" operator), and in this case one of them is not met ("a point that you can't see"), your point of origin for a spell that requires a point you select within range can be on the other side of a Wall of Force from where you are casting the spell. The Wall of Force will not block the casting of such spells at a point of origin on the other side of it. For example, a Fireball or a Fire Storm spell. This analysis would also apply to casting such a spell through a crystal window.

An area of effect from a spell that its point of origin is on one side of a Wall of Force may or may not affect a target on the other side of the Wall of Force

If a spell description says that its area of effect spreads around corners, and the area of effect can spread around the Wall of Force from the point of origin on one side of the Wall of Force and can reach the target on the other side, the target suffers the spell's effects, otherwise, it doesn't. For example, a target inside a spheric Wall of Force will not suffer the effects from a Fireball cast outside the sphere. Also, targets outside of a spheric Wall of Force will not suffer the effects of a Fireball cast inside the sphere. But if the target is 5' behind one of the 10' x 10' panels of a Wall of Force that spreads 100' long and a Fireball is cast with a point of origin 5' from the other side of the Wall of Force, that target will suffer the effects of such Fireball.

If the Wall of Force blocks the spreading of a physical area of effect, such as a cone whose effect does not spread around corners, the target behind the Wall of Force does not suffer the effects of the spell. For example, a Cone of Cold spell when the Wall of Force covers the whole cone cross-section.

Answer 6

The wall of force has a number of different configurations. Some of them may block line of sight but at least one does not.

The spell's description says that the wall can be "free floating or resting on a solid surface."

It also states that it can be formed into a "hemispherical dome."

Assuming that one wants to be able to cast spells on a target trapped inside a wall of force then by RAW the wall can be formed as a hemisphere suspended in mid-air roughly six inches off the ground, which should be sufficient to both trap most targets inside but yet give the caster sufficient line of sight to affect the target inside.

Answer 7

I believe the ruling about targeting makes it pretty clear after further review:

A Clear Path to the Target

To target something, you must have a clear path to it, so it can't be behind total cover.

This is the rule. You must have a clear path. A wall of force is clear, but it is not a clear path.

If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

This If statement clarifies a specific example and what happens in that example - using it to derive the rule is a mistake. It is saying that if you target something you cannot see (which many spells do not require you to see your target, simply to pick a point), and then it turns out there is also not a clear path to that target, then the effect appears on the near side of the (presumably unseen) obstruction to the path.

The If statement is merely a ruling of where to place the effect if both those cases are true, it does not say that both cases must be true to block targeting.

Answer 8

A wall of force can only be destroyed by a disintegrate spell and it extends to the ethereal plane. An exception to this rule is a spell where you target a place/something you can see with finger of death or a similar spell:

You send negative energy coursing through a creature that you can see within range, causing it searing pain. The target must make a Constitution saving throw. It takes 7d8 + 30 necrotic damage on a failed save, or half as much damage on a successful one.

A humanoid killed by this spell rises at the start of your next turn as a zombie that is permanently under your command, following your verbal orders to the best of its ability.