What is an effective system for a random shot from a ranged weapon in 3 dimensions? [closed]

Question

A couple of times in my current campaign (D&D 5e), one of my players has elected, due to blindness, or darkness, to make a random shot in a random direction (including vertically, not just horizontally) without being able to see. At one point I am sure that I read about a DM's system using a d20 to represent degrees in a circle to represent a random shot, but I can no longer find it (I thought it was in SilverClawShift's campaign archives). Does anyone else know of an effective system to represent a random shot?

I was thinking about a system like that in which you would roll a random number for direction, but I need a 3D simulated roll - up and down and left and right, but also in a 360-degree circle, not just the 4 cardinal directions .

Answer 1

I doubt you would find a rule specifically about firing in a random direction. However, other places such as the confusion spell use a method for determining a random direction (in this case, a direction for wandering off).

To determine the direction, roll a d8 and assign a direction to each die face

You can easily use the same method to determine a random direction to fire in (1 = North, 2 = North-East, 3 = East etc).

If you really want a random direction within 360 degrees, then dice may not be your answer. 0 - 360 degrees lie in a continuous number line (infinite possibilities) while dice can only ever give you a discrete answer and so could never give you 'every' direction! The only option would be to use another 'continuous' mechanism such as the old 'spin the bottle' (or some little spinner arrow like you get in some board games). Then use that to roughly line up with a direction. This could all over-complicated things though. Sometimes its better just to keep things simple.

Slight aside:

The DM should always know where the enemy is, even if the player doesn't. You may want to allow a Perception check to see if they can hear the rough direction of an enemy.

Regardless, a player can generally just say which direction they are shooting in - it doesn't have to be random. And the shot should still require an attack roll (with disadvantage) just in case they happen to pick (or roll) the lucky direction.

Answer 2

This system already exists. It's called 'Blinded'; roll with disadvantage

Which is to say, that a 360° (or more) system is overkill and largely pointless. If you look through enough of my answers, you'll likely see several iterations of "don't make players roll if it doesn't add anything".

"but there's a .05% they could hit and a 5% chance from there that they could crit!" is effectively nothing, and since D&D doesn't use decimals, it rounds down to nothing.

Either roll with disadvantage, or tell the player that the shot is too hard and that they can't roll. If the player still chooses to fire an arrow, then you describe their miss. "You choose a direction and snap off a shot. an instant later, you hear the sound of arrow hitting cobblestone."

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If you absolutely MUST use some sort of system...

I'll actually answer your question. First: scrap vertical movement. The system is already clunky, as is.

If you want something that vaguely accepts a 360° shot, every face on a d20 represents 5%; 5% of 360 is 18. This means you can represent 18° for each d20 outcome.

Using math (Side-Side-Side or Angle-Angle-Side), we can determine how many degrees hits a 5-ft square (or cube) at certain distances.

Appoximately:
15ft is 18°, or 1/20
10ft is about 28°. It's really like 1.5/20, but I would give it the 2/20
5ft is almost 54°. close to 3/20
1ft is 135°. close to 7/20

Again, this is mostly an exercise to point out how convoluted the system would be; you should just use blinded.

Answer 3

Given what you are asking; your player wants a truly random direction and angle, you could roll 1d8 for direction, and just count the squares surrounding the player and ignore the square behind the player, (or use NSEW for even and in between odd (NE, NW, SE, SW)), then roll a die for angle, say from 0-180, because over 180 is going to change the direction. You could roll a d6 and multiply it by 15 for a 90 degree angle or d12 multiplied by 15 for the full 180 degrees. Even then, since you're likely adjudicating theater-of-the-mind or with a two dimensional grid, the random angle will probably just help ensure a miss, but hey, if it's what the player asked for...

It seems a bit silly though, but seems useful if someone threw a loaded crossbow and it goes off when it hits the ground.

Answer 4

My system for random directions is to roll a d8, and use the direction that the pointy end of the die is facing as the result. The number rolled is irrelevant, but you could use it for elevation or distance if needed.

If you need elevation as well, you could use percentile dice instead, and use the direction of the 1's die for direction, and the value of the number for the elevation angle. Re-roll 90's. Or you could use both dice in analog fashion, as with the d8.

Answer 5

You could use an online random number generator and do a random number between 1 and 360 degrees. You wouldnt have to be precise to the degree but that could give you an idea of the direction then flip a coin to decide for up or down.