D&D 5E 5E Cone & Radius Question

[Dax Doomslayer]

Hi Folks,
A quick (and probably stupid) question. When casting spells with cone and radius effects using a 1" square grid, does the spell effect any square that the cone goes through even if it's less than say half the square or minimally cuts through it? How is this judged? Any input is greatly appreciated. Also, if anyone has any spell effect templates they know where to find / buy it would also be helpful!! Thanks.

 

[AaronOfBarbaria]

It's up to the DM to decide, since even when using a grid neither movement nor the placement of spell effect areas are "snapped" or "locked" to the grid.

Personally, I go with paper cut-outs in the appropriate sizes and shapes, and have a player physically orient the effect as desired above the minis on the table, and if the cut-out is above any part of the base (not the figure, since some poses are very spread out, and some aren't) that creature is in the area of the spell effect.

 

[Sage Genesis]

5e's grid rules are a little bit undercooked, probably because they're not the default.

I would recommend just lifting 3e's approach to spell AoE wholesale. It's close enough and overall a fairly reasonable approach for grids. The Pathfinder SRD has a helpful picture:
http://paizo.com/pathfinderRPG/prd/magic.html#aiming-a-spell

 

[Lidgar]

From page 251 of the DMG:

"If an area of effect is circular and covers at least half the square, it affects that square."

I would assume the same applies for cone effects.

 

[Rya.Reisender]

Yeah, for me it at least has to hit the cell center to hit the unit on the cell. A creature doesn't even occupy the whole cell so it wouldn't make much sense if that create would be hit if the just corner is hit by the spell.

Generally when playing grid-based, I convert the round AoEs to grid AoEs (for cone you need to calculate two AoE, one for vertical/horizontal AoE and one for diagonal AoE).
Like this:

 

[Dax Doomslayer]

Thanks for the replies folks. I saw that in the DM's guide after I posted but as indicated it oddly didn't address the cone situation. I think that's what I'll go with!! I appreciate everyone's input.