D&D 5E Square grid, what's the difference between a square and a circle?

[Hussar]

At the end of the day, how fiddly do you want to get?

My 5e game has gone back to 1-2-1 counting and I hate it. It's such a major PITA with so little gain. For one, most people make mistakes at least once per session with this counting method. Secondly, 5e has 25 foot movement, which doesn't work with 1-2-1 counting. You wind up at points were you cannot move diagonally because you only have 5 feet of movement left all the time. In a diagonal, 5 foot wide corridor, a 25 foot movement gets reduced to 20 feet, even though the corridor is perfectly straight. A corner case example, sure, but, it recently came up, so, it was in my head.

Also, I LOATHE the "I'm a wizard, so, I can cast my spells perfectly placed to miss allies but hit enemies, despite the fact that I'm trying to manoeuvre a 20 foot blast radius from 50 feet away." It's ludicrous. Casting AoE's like that should require attack rolls.

I much, much prefer 4e's grid system with square effects. It's just so much faster and easier. And the extra accuracy you gain with 1-2-1 counting is lost in play due to user errors. It is more accurate. That's true. But, the vast majority of the time, that accuracy is meaningless (who cares if your fireball is a square or a circle when you're hitting 4 targets 5 feet apart?) and just bogs down play.

 

[EzekielRaiden]

Areas of effect are centred on the intersection of squares, not on entire squares in 5e per the DMG, p.251. So a circle (or sphere) of radius r is a square (or cube) of side length 2r. A fireball, for example, is 8 squares across.

When I said "in this geometry," I was referring to the provided image and the example of the spaces one could walk to, which (IIRC) is also not how 5e handles things...so, no, I wasn't referring to 5e at all, I don't think. I was, as stated, referring to chessboard/Chebyshev distances, which even the OP made clear ("I know Fireball is centered on points so assume it's a Thunderwave or something.") In that metric, where a grid tile actually sits at the origin ("zero" in terms of squares moved or a "burst radius" of zero), circles of radius r move one square out in all directions, meaning they are squares with odd-integer side lengths, or 2r+1. It's identical to "on an infinite chessboard, what area can a King move to in r moves?"

 

[Shiroiken]

It's in the DMG p254 Area of Effect & also my personal experience & observation of comments other people made in some other thread (! quality referencing) though I may be confirming my bias.

Anecdotal evidence aside, I withdraw my previous objection. I didn't have a DMG handy, and had overlooked that rule.

The point of playing on a grid is to avoid having to deal with all the finicky geometry & precise measurements - if I want that I have Warmachine. So snapping to a grid makes sense if you are using one, else break out the protractors, tape measures, range gauges & laser LOS markers.

You sound like it's an either/or scenario, but it doesn't have to be. I don't require the Point of Origin to be on a grid-line, and haven't had a problem with it. It's called judicious use of common sense by the DM.

Moonbeam came up in my TOTM Google hangout game & I noted it as being oddly different from my expectation. It was also raised here somewhere wrt the ranger power horde breaker (sic?) where separate targets have to be within 5' which might well be ruled differently on a grid or not. I advocated a liberal approach.

Especially since playing on a grid is a variant anyway, it's probably best to get your DM's approach BEFORE these things come up.

 

[redrick]

If you're using Roll20, you can just turn Euclidean measurement on, and then you're good to go as far as the geometry's concerned.

Yep, Euclidean all the way. But, if you have the actual grid display turned on, it still snaps all your tokens into the grid unless you hold down alt every time you move something. So, when drawing large dungeon maps ahead of time, I'd overlay a low-opacity grid in GIMP. It allowed us to eyeball scale at a glance, because, when dealing with big cavernous spaces, it can be hard to tell if you are looking at a room that is 30 feet across or 200 feet across depending on what your zoom level is.

But, yes, Roll20 handles all the weird measurements for you, and even lets you calculate path distance very quickly. I had a 20' radius token that I would drop on for spell effects, which was nice for some of the persistent spells that the Ranger would cast.

All tangential to OP, of course. Sorry.

 

[Scorpio616]

Also, I LOATHE the "I'm a wizard, so, I can cast my spells perfectly placed to miss allies but hit enemies, despite the fact that I'm trying to manoeuvre a 20 foot blast radius from 50 feet away." It's ludicrous. Casting AoE's like that should require attack rolls.

well if you are running the game, just rule the caster picks the square, but the intersection of origin is rolled on a 1d4. I think one edition of Wotc Star Wars used that for grenades.

But do note, D&D characters are fairly competent individuals even by the time they get fireball. Characters are generally going to be rolling at least +5 to hit by then, which will almost always hit the least agile of human beings (3 dex = AC 6, +5 to hit = miss on a 1), which probably should still be harder to hit than the ground.

 

[transtemporal]

I cast Firecube! Call lightning cylinder! Burning cone!

 

[Zander]

Also, I LOATHE the "I'm a wizard, so, I can cast my spells perfectly placed to miss allies but hit enemies, despite the fact that I'm trying to manoeuvre a 20 foot blast radius from 50 feet away." It's ludicrous. Casting AoE's like that should require attack rolls.

In the 5e campaign I'm currently in, we have rotating DMs of which I'm one. One of the other DMs agrees with you. He gives creatures in the 5' strip around spell areas a 50% chance of being affected by it which makes it much harder for spellcasters to attack enemies and avoid allies (unless they're evokers who can avoid a RAW-limited number of allies).

When I said "in this geometry," I was referring to the provided image and the example of the spaces one could walk to, which (IIRC) is also not how 5e handles things...so, no, I wasn't referring to 5e at all, I don't think.

I was remiss in not clarifying that I understood that you were responding to the OP's specific question. I just wanted to point out the general rule that squared circles are centred on intersections, not whole squares.

 

[Hussar]

well if you are running the game, just rule the caster picks the square, but the intersection of origin is rolled on a 1d4. I think one edition of Wotc Star Wars used that for grenades.

But do note, D&D characters are fairly competent individuals even by the time they get fireball. Characters are generally going to be rolling at least +5 to hit by then, which will almost always hit the least agile of human beings (3 dex = AC 6, +5 to hit = miss on a 1), which probably should still be harder to hit than the ground.

That's an idea that I like. It would stop a lot of the "I'm going to precisely place this 40 foot sphere of fire so that it hits this guy, but misses the guy next to him.

AFAIC, the gains in accuracy of 1-2-1 aren't worth the time lost trying to fiddle around with pixelated circles. Never mind when someone casts a 60 foot cone, 30 degrees off of true.

 

[Pickles III]

You sound like it's an either/or scenario, but it doesn't have to be. I don't require the Point of Origin to be on a grid-line, and haven't had a problem with it. It's called judicious use of common sense by the DM.

Do you let characters move outside the squares too? Commons sense says they can.

It's a slippery slope to just measuring everything - also a valid playstyle, if archaic, that does not even seem to be mentioned by the books. (I can't remember what we used to do in the 80s - I know we played on a big gridded board with minis but I can't remember whether we used the grid for gameplay or tapes.)

Anyway you can do what you like it won't kill the game.

edit: the tone of this was supposed to be jovial which I suspect does not come across so

 

[Pickles III]

That's an idea that I like. It would stop a lot of the "I'm going to precisely place this 40 foot sphere of fire so that it hits this guy, but misses the guy next to him.

AFAIC, the gains in accuracy of 1-2-1 aren't worth the time lost trying to fiddle around with pixelated circles. Never mind when someone casts a 60 foot cone, 30 degrees off of true.

I used to do the wobbly fireball targeting when I started 3e. I also at one point would ask players to pick the target point & only then would we get out our AOE template to see what it hit. I can't remember why I stopped other than it just doesn't seem relevant any more & it's slow. I have no interest in revisiting that for 5e/4eD&D.

As to the 1-2-1. it's a lovely clean approximation but like you say materially slows things down.

I also find counting the move in 5' increments instead of squares slows things down for no value. I wish they had gone with all measurement being in "fathoms*" which are strictly 6' but can be 5' for gameplay. Then you remove a factor of 5 & make playing on a grid very straightforward while retaining a more natural flavour than "squares" gives.


*The mini game Helldorado used fathoms but other words would do.