Line Spells / Lightning Bolt

[Mistwell]

Old thread but this topic comes up in our games. A prior ruling does seem to indicate you can cast down the edge of a line of squares, hitting 50% of each square to either side of that edge. And if you hit 50% of a square, according to the rules, you damage a creature in that square fully. So, a line which extends 30' can, if cast along that edge, impact 12 squares rather than 6. See this tweet (there is an affirmative response to both options, if you click on the tweet):


Does anyone know of a more recent or better rules clarification which contradicts or affirms this ruling?

 

[Benjamin Olson]

Yes it can cover two side by side 5 foot squares, just as any area of effect can effectively hit more 5x5 squares by not lining up strictly according into the grid and doing partial squares at the peripheries. Some areas of effect are even circular and intrinsically have to only cover partial squares at their edges. Allowing such for Lightning Bolt has the added benefit of narrowing the usefulness gap between that spell and Fireball.

 

[Charlaquin]

Old thread but this topic comes up in our games. A prior ruling does seem to indicate you can cast down the edge of a line of squares, hitting 50% of each square to either side of that edge. And if you hit 50% of a square, according to the rules, you damage a creature in that square fully. So, a line which extends 30' can, if cast along that edge, impact 12 squares rather than 6. See this tweet (there is an affirmative response to both options, if you click on the tweet):


Does anyone know of a more recent or better rules clarification which contradicts or affirms this ruling?

Jeremy Crawford effectively confirmed this ruling here:


Technically the question was about cones rather than lines, but the answer that spheres are the exception to AoE effects being able to target any creature whose space they cover any amount of would mean this is a valid way to place a 5 by X foot line. As usual for Crawford’s rulings, I think this ruling is consistent with an overly literalistic reading of RAW, but flies in the face of common sense.

Personally, I rule that if less than half of a square is covered by an AoE (sphere or otherwise), creatures in the square can be targeted by the effect, but have advantage on their save.

EDIT: Also, note that by RAW AoEs always originate from an intersection on the grid (i.e. a corner), so not only is diagram 1 in Josh Fredrickson’s tweet valid, diagram 2 isn’t, because it places the origin point in the middle of a square.

 

[jgsugden]

Under RAW, there is no grid. Grids are optional rules.

In Xanathar's, we get two methods of adjudicating that are DRASTICALLY different for lines.

The Token method allows us to launch lines in only orthogonally or diagonally. You get 8 choices for how to drop a lightning bolt, and can start it from any of the 8 squares around you (although 8 of those options will include you).

The Template method, on the other hand, allows you to do a lot more. You take a 1 inch by 20 inch template and place it adjacent to your square. Any square under the template, regardless of how little touches it, is impacted. This is interesting in that the origin square (occupied by the caster) can easily end up being partially covered by a tilted template if they are not careful, although there is usually a way to avoid this if you are careful. If you use this method, you can get real sneaky with a lightning bolt.

In my games, I rule a little differently. I use the template method, but a square is only included if the center of the square is touched by the template. This would allow you to run a line directly between two squares and get both, but if you tilt it at all, it only gets 1of each side (with the ability to get one set of 2 squares down the path if you think about it. I consider this to be the best way to adjudicate all of this stuff - template method, with the center being covered to include a square.

 

[Mistwell]

Under RAW, there is no grid. Grids are optional rules.

Optional rules are rules that are written. In the book. They are RAW.