How are "non-damage" attack rolls determined?

Question

In 5e, I have not found a system that works with "non-damage" attacks. Eg, throwing sand in someone's face, to temporarily blind them.

Because this is not an attack that involves their AC, does it go against a (in this case) Dex saving throw? And how is the outcome determined?

Answer 1

[Note to those who have up-voted this answer: I've posted an alternate theory, prompted by @Escoce, which I ask you to consider. Perhaps you find that compelling and wish to retract your vote here.... -nitsua60]

What you call a "non-damage attack" I'd call a contest

To be clear: it's not obvious to me that all non-damaging hostile actions must necessarily be contests. But the example you ask about seems to be one. Here's why:

You don't want to attack with the sand...

Since sand isn't a weapon, per se, you'd have to treat it as an improvised weapon. But the only thing the improvised weapon rules are built to handle is damaging your target, which isn't your goal.

You want to blind.

Battle often involves pitting your prowess against that of your foe. Such a challenge is represented by a contest. (PHB p.195, emphasis mine)

We're pitting your "throwing sand" prowess against your opponent's "closing eyes in time" prowess. (That's my read, at least.) Is that contest described? Nope. But:

This section includes the most common contests that require an action in combat: grappling and shoving a creature. The DM can use these contests as models for improvising others. (loc. cit., emphasis mine)

So what's the resulting contest look like?

Contests are something you need to improvise yourself, but here's how I'd handle it. I'll explain the thought process behind this one afterwards:

You can use one of your attacks to throw sand in the face of your opponent. Initiate a DEX contest to see if the opponent is blinded. At the beginning of each of the sanded creature's turns he makes a DC10 CON save to clear the condition. As an action the creature can make an attempt to blink away the sand: another DC10 CON save. At the end of the target's third blinded turn, the condition ends.

(Picking up the sand is interact with object, and the DEX check takes up one of your attacks on your turn.)

Here's my thinking behind creating it this way:

1. Picking up the handful of sand is an easy "interact with object", since it's at least easier to just grab whatever-your-hand-hits than to pick up a dropped axe (the example given on PHB p.190).

2. You use your Attack action to throw the sand. As with both Grappling and Shoving, if you can make multiple attacks with your Attack this replaces one (PHB p.195).

3. Decide how, exactly, the checks will be contested. Both throwing and dodging the sand have to be DEX checks, as thrown weapons and dodging magical effects implicate DEX modifiers and DEX saves, respectively. Are any of the skills relevant? I don't find the descriptions of Acrobatics, Sleight of Hand, or Stealth particularly apropos, so I'd rule straight-DEX.

4. What are the effects of success? Being blinded makes the target auto-fail checks relying on sight, disadvantages target's attacks, and advantages attacks against the target (PHB p.290). That seems a little harsh, but creating a dialed-down custom condition will become way too complex. Maybe we can tune it down with how the blindness ends though:

   • Clearing the sand out of one's eyes: being magically blinded allows for a CON save every turn (Blindness/Deafness, PHB p.219). I think the sand should be no harder than that to clear away. The CON save for the spell is against the caster's spell save DC, almost certainly >= 13. So maybe you go with sand has a CON save of 10 for ending the condition.

   • I'm going to make a few more concessions to the target: they can use an action to try to clear, and the sand'll clear away naturally after a certain duration. (That's what tears are for!) I didn't want to run the experiment at home, but 18 seconds (3 turns) seemed reasonable to clear it away. I tell my kids, when somethings in their eyes, to "close your eyes, count backwards from ten, and blink five times." If it works in the (literal) sandbox, it's sure to work in battle. Right?

So, we end up with a quick DEX check with some concessions for a relatively easy save-ends.

---

The question Can I give the blinded condition through an improvised action? ends up looking at the same situation: flinging sand at an opponent. The accepted answer there disagrees with mine, making that question is a good place to look at an argument against my interpretation.

Answer 2

Handle non-damaging attacks as a weapon.

First, credit where it's due: in some chatting with @Escoce I came 'round to this being a reasonable position worth considering in contrast to the my other answer to use a contest. I encourage you to compare the two and use whichever satisfies.

Take a look at the Weapons table on p.149, all the way down at the bottom:

Net          1gp    --          3 lb.    Special, thrown (range 5/15)

The PHB has a weapon with all the features you want: a ranged weapon which does no damage and on a successful hit produces a condition!

So what if we treat stuff like sand & dirt as a special weapon that's readily available (it's everywhere!), and pattern it after the net? Here's what it might look like, I'll explain the thought process afterwards:

Thrown Sand. Finesse, light, thrown (range 5/15), improvised.

A creature hit by thrown sand is blinded until it can clear its eyes. Thrown sand has no effect on creatures that just wouldn't care (you can figure it out). A creature makes a DC10 CON save at the beginning of each of its turns to clear its eyes. A creature can also take an action to clear away sand, making another DC10 CON save. At the end of a creature's third turn blinded by sand that sand is cleared from its eyes. Thrown sand is neither a simple nor a martial weapon. [I.e. you aren't proficient in throwing sand.]

Thought process

1. "Finesse." It's a thrown weapon, which would key off of strength, but I automatically think of "aiming for the eyes" as a DEX thing, so I'd like it to benefit from high DEX. But STR does make sense--maybe a strong person can just do a better job of grabbing a whole scoop-full and blasting their opponent with it.
2. "Light." I like being able to make a little stab with one light weapon and then following up with the sand.
3. "Thrown." The range of the net feels right. (I didn't run an experiment with measuring tape, but I've seen my kids make this attack many times in our literal sandbox.) Unfortunately, it looks like you're perpetually disadvantaged with sand, then. Too bad.
4. "Improvised." I think the default should be that one is not proficient with thrown sand, but we'll hearken to p.147's "at the DM's option..."
5. "A creature hit..." This might be contentious, but we'll consider someone's chance to dodge as already being baked into the target's AC, which is some reflection both of absorbing and avoiding blows. (I believe this idea was explicit in earlier versions; in 5e it's inferred from the first paragraphs of each armor type's description on pp.144-145.)
   • I would argue this is an improvement over the contest method I suggested in my other answer. In that one it's only a target's DEX that protects them. Now, the high-DEX, lightly-armored character and the low-DEX character wearing armor with a helmet gain protection from sand-in-the-eyes.
6. The save-ends follows exactly as in my other answer suggesting a contest, with the same reasoning:

   • Clearing the sand out of one's eyes: being magically blinded allows for a CON save every turn (Blindness/Deafness, PHB p.219). I think the sand should be no harder than that to clear away. The CON save for the spell is against the caster's spell save DC, almost certainly >= 13. So maybe you go with sand has a CON save of 10 for ending the condition.

   • I'm going to make a few more concessions to the target: they can use an action to try to clear, and the sand'll clear away naturally after a certain duration. (That's what tears are for!) I didn't want to run the experiment at home, but 18 seconds (3 turns) seemed reasonable to clear it away. I tell my kids, when somethings in their eyes, to "close your eyes, count backwards from ten, and blink five times." If it works in the (literal) sandbox, it's sure to work in battle. Right?

Answer 3

I would argue that this is indeed an attack roll. You are attacking with the sand. In older versions of the game, it was called "to-hit" which I think better explains what the intent of the die roll is about, however it is really just a vernacular difference. You are indeed attacking with the sand.

I would treat further treat this as an area of affect attack, anyone within the albeit short range of the "cone of sand" should take a Dex save to avoid being blinded by the affect of the attack.