Under what circumstances does an antimagic field suppress the casting of a spell?

Question

The antimagic field spell says that "within the sphere, spells can't be cast", and spells out some more of the specific effects of this:

Targeted Effects. Spells and other magical effects, such as magic missile and charm person, that target a creature or an object in the sphere have no effect on that target.

Areas of Magic. The area of another spell or magical effect, such as fireball, can't extend into the sphere. If the sphere overlaps an area of magic, the part of the area that is covered by the sphere is suppressed. For example, the flames created by a wall of fire are suppressed within the sphere, creating a gap in the wall if the overlap is large enough.

(There are also several other effects, but they relate to suppression of already-cast spells, magic items, etc., rather than the casting of new spells.)

These rules alone seem to leave some corner cases ambiguous. For example, none of the named list of effects specifically says that spells cast by a creature inside the field are suppressed, but it seems like this would be the case based on the introductory text before that list. So I would like to ask about some specific corner cases.

In which of the following situations would antimagic field suppress the spell or otherwise prevent it from affecting the target?

1. The spell's caster is inside the field, while the target or area of effect is entirely outside the field.
2. The caster and target are on opposite sides of the field, such that the line of effect passes through the field.
3. Same as (2), but the spell's description explicitly says it launches a projectile, beam, ray, or line-shaped area of effect at the target, as in scorching ray, disintegrate, or lightning bolt, such that the projectile or beam's path would take it through the field.
4. A creature is standing just outside the field, and an area of effect spell that would normally hit the creature is cast centered on a point within the field, e.g. fireball.

I'm fairly sure I know the answers to (1) and (2), but (3) and (4) seem harder to answer.

Answer 1

It must be kept in mind that an Antimagic Field only suppresses a spell, it does not dispel it.

What I mean by that is that a spell is not destroyed when it passes through an Antimagic Field. Think of it as magical destructive interference localized on one spot. While the magic cast outside of the sphere interferes with the antimagic in the field, the effect of the spell can't be manifested. However, as soon as the magic passes that field the effects can reappear. This is why summons only vanish temporarily when an Antimagic Field crosses their paths and reappear instantly after.

A creature or object summoned or created by magic temporarily winks out of existence in the sphere. Such a creature instantly reappears once the space the creature occupied is no longer within the sphere.

Now let's check out the list in order:

1. Spellcaster inside the field. First and foremost, the description of Anitmagic Field explicitly states that spells cannot be cast from within the sphere.

   Within the sphere, spells can't be cast, summoned creatures disappear, and even magic items become mundane.

2. The line of effect passes through the sphere. In this case, the spell is not suppressed in any way, as neither the caster nor the target are in the field and the field does not act as cover from spells.

   Spells and other magical effects, such as Magic Missile and Charm Person, that target a creature or an object in the sphere have no effect on that target.

3. The spells passes through the field. This can be seen in two different ways: an AoE line or a magic projectile like Firebolt. Either way, the answer is the same, which is that it is suppressed while in the field and is no longer suppressed outside of it. For an AoE effect, the area of the spell that overlaps the field is suppressed, which means that a Lightning Bolt would stretch to the beginning of the field, then be suppressed, then reappear after the field as stated in the spell description. A Firebolt would travel in a straight line, also disappear as it passes through the field and reappear as it emerges from the other side.

   The area of another spell or magical effect, such as Fireball, can't extend into the sphere. If the sphere overlaps an area of magic, the part of the area that is covered by the sphere is suppressed. For example, the flames created by a Wall of Fire are suppressed within the sphere, creating a gap in the wall if the overlap is large enough.

4. A spell is cast on a point within the field. The answer is the same as the answer for (3). Although the "target" for the spell is a location within the sphere, the spell itself is not a targeted spell but an AoE spell. This behavior is the same as that of a Globe of Invulnerability.