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

[Pickles III]

I'd say so, 20' radius spells are potent enough as it is, giving them an area boost just because folks are playing on a grid is like giving an iron club to an oni.

Turning it into a firebox also stifles creativity and intelligence play as that robs the characters from airbursting spherical areas to reduce area size at ground level

Playing on a grid costs you area anyway assuming you snap to the grid which everyone seems to, it is stated as such in the RB.

If 2 figures are standing with one square between them then they cannot both be hit by moonbeam with its 10 diameter if that has to cover squares. If they are in TOTM it can be centred exactly between them.

And any game that is going to require people to do geometry or trig in 3 dimensions to work out the Area of effect of a Fireball is definitely not for me. It's not even interesting creativity - it's either in your toolbox of ways to manipulate the rules to improve spells or it is not.

(Notwithstanding I did have fun cone of colding downwards with flying Ogre Magi a few years ago as that turns a cone into a circle but that was in a Totm encounter & they were trying to blast an invisible rogue, invisible creatures on both teams is awkward.)

 

[Shiroiken]

Playing on a grid costs you area anyway assuming you snap to the grid which everyone seems to, it is stated as such in the RB.

If 2 figures are standing with one square between them then they cannot both be hit by moonbeam with its 10 diameter if that has to cover squares. If they are in TOTM it can be centred exactly between them.

I'd like to know where that rule is located. I just looked up "Variant: Playing on a Grid" (PHB 192) and "Areas of Effect" (PHB 204), and neither states that you snap to the grid for spells. That was the rule in 3E, but it does not appear to have carried over into 5E. I would guess then, that "everyone" (as you referred to them) is simply inferring the 3E rules without actually thinking about it.

Thus, in your example, you CAN cast Moonbeam on 2 characters with 5' space between them. Some (like myself) might rule that they have advantage or cover on their save (since you are getting less than half their space), but that would vary from DM to DM.

 

[aramis erak]

You can easily convert to radias combat, but it has to be everything not just AoE spells. Circle spell on square grid means you have partial squares, so you would have to account for those in the rules. You could use a pixel circle, but that is complex and doesn't add much for the trouble

If one uses templates, it's not a big issue. The guiding principle for pixelating is that, if the circle touches or passes the centerpoint of the square, that square is in the effect.

So, for your sample 25' radius

••••###••••
••##•••##••
•#•••••••#•
•#•••••••#•
#•••••••••#
#••••#••••#
#•••••••••#
•#•••••••#•
•#•••••••#•
••##•••##••
••••###••••

 

[FormerlyHemlock]

From the blue square, a character with a 20 ft range weapon can hit all the white squares

Eh, what? No he can't. The square in the corner is 28 feet away from him--he can't hit it with a 20 foot weapon, nor the squares adjacent to it, nor any of its mirror images.

Feel free to ignore that fact in play, but you can't just state as a given that he can hit all the white squares with a ranged attack when he clearly cannot. Fireball and ranged attacks are exactly the same in this.

 

[GMMichael]

Or, to put it more simply, is the area of effect of a fireball a square?

I know there are other ways to deal with this (like hex grids or no grids)

Rule zero.

Personally, or impersonally, my character is going to be a little traumatized after seeing a fire-cube. That cute little girl on the tricycle over on the sidewalk, who was clearly not in danger of a globular fireball? Poof. Gone.
[MENTION=6706099]Sage Genesis[/MENTION] wrote the response that I wanted to write. +1.

 

[Pickles III]

I'd like to know where that rule is located. I just looked up "Variant: Playing on a Grid" (PHB 192) and "Areas of Effect" (PHB 204), and neither states that you snap to the grid for spells. That was the rule in 3E, but it does not appear to have carried over into 5E. I would guess then, that "everyone" (as you referred to them) is simply inferring the 3E rules without actually thinking about it.

Thus, in your example, you CAN cast Moonbeam on 2 characters with 5' space between them. Some (like myself) might rule that they have advantage or cover on their save (since you are getting less than half their space), but that would vary from DM to DM.

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.

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.

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.

 

[MG.0]

I don't use miniatures or a grid. It slows things down too much. Plus, where do you put the snacks?

 

[redrick]

If you consider all paths across a grid square to have the same length (5 ft), then the logical conclusion of that is that circles are in fact squares. This was how 4e areas worked.

Of course, you could rule it differently. Personally, I don't find it that hard to draw rounded corners with my mind's eye. Or you can use templates.

I can't stand the idea of discrete squares myself. Whenever I play with a gridded map (because sometimes it's nice to draw a map with wet-erase markers on my chessex mat, or because, on Roll20, it made eyeballing room sizes on massive dungeon maps easier), I always make a point of placing all my monsters in between grid squares. But that's just me, and I appreciate it's not for everybody.

 

[TheCosmicKid]

I can't stand the idea of discrete squares myself. Whenever I play with a gridded map (because sometimes it's nice to draw a map with wet-erase markers on my chessex mat, or because, on Roll20, it made eyeballing room sizes on massive dungeon maps easier), I always make a point of placing all my monsters in between grid squares. But that's just me, and I appreciate it's not for everybody.

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.

 

[Zander]

You are correct; a circle of radius r centered at the origin in this geometry is a square of side length 2r+1.

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.