# Do projectile spells arc or travel in a straight line?

Are projectile spells like fireball affected by gravity and arc from their origin to their destination, or do they travel in a straight line?

I’d like an explanation from both an official and logical standpoint.

For example can I lob a fireball over a wall assuming there’s no ceiling in the way if I’m also using a spell that allows me to see targets through the wall. I once heard it compared to a catipult and that made me wonder if you could use it similarly.

• Why do you ask? What problem are you trying to solve? Jun 13, 2019 at 13:46
• Comments are not for extended discussion; this conversation about the validity of the edit which introduced a major clarification to the question has been moved to chat. Jun 13, 2019 at 17:59
• You should take an other exemple than fireball, because fireball is "point somewhere, and an explosion occur there" so there is no projectiles involved
– Rorp
Jun 14, 2019 at 9:01

## Spells are not affected by gravity unless otherwise noted

Really, it shouldn't matter. D&D is not a physics simulator, as tends to get pointed out frequently here, with the additional caveat that they only do what they say they do.

The general rule is really that things like gravity work as expected regarding 'real world' situations, such as its affect on objects and creatures. But anything else, like spells, you just have to go by the rules.

Fireball says:

A bright streak flashes from your pointing finger to a point you choose within range

Emphasis mine. You select the point. That's where the fireball blossoms. How the 'bright streak' moves to this point is irrelevant.

Other rules worth pointing out are the "Clear path to target", which has a tacit assumption that the path is a straight line.

And...regarding areas of effect:

For a sphere (like a fireball):

You select a sphere's point of origin, and the sphere extends outward from that point

Again, pointing out the fact that you simply choose the point of origin.

And for a line:

A line extends from its point of origin in a straight path up to its length

Here, the straight path is explicitly pointed out.

# Official & Logical: It doesn't matter for the rules

D&D is not a physics simulator and it does not care about arcing or straight lines. There are rules for targeting a spell, and if those are met, the spell can be cast and can hit. It doesn't matter to the game if they arc, travel in a straight line or do a tango dance before reaching, because that makes no difference for the rules.

If for some reason you really wish to know if a fireball arcs or moves in a straight line in your specific game, ask your DM to make a personal interpretation, because they're really the only person at this point who can make a "ruling".

# Straight line it is

I'll be quoting from the rules as written on D&Dbeyond. Emphasis mine.

## Targets

A typical spell requires you to pick one or more targets to be affected by the spell's magic. A spell's description tells you whether the spell targets creatures, objects, or a point of origin for an area of effect (described below).

### 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.

So no, you can't lob spells over walls, therefore it must be a straight trajectory.

• Also in the basic rules on page 84 Jun 13, 2019 at 17:21
• Can you maybe more clearly link why "clear path" necessarily means "straight path? Nowhere in either rule does it say that the path must be linear there (even though it is often assumed that it is). Filling in that blank might be what helps OP understand here. Jun 13, 2019 at 17:52
• @Rubiksmoose - that's exactly why I also emphazised "can't be behind total cover" and "point you can't see." We don't see in a parabolic arc, do we? ;) Jun 14, 2019 at 16:59
• For sure! But the question does ask us to assume that you can see through the wall. I'm not sure if that changes anything or if it's just me who's not understanding. Jun 14, 2019 at 17:37
• I think it still counts as behind cover, but I'm going to check. Jun 14, 2019 at 17:56