# When casting a cube spell on a hex grid do you pick a honeycomb for origin or an intersection for origin?

Hypnotic pattern: You create a twisting pattern of colors that weaves through the air inside a 30-foot cube within range.

This question has bugged me for awhile because my DM likes to play with hexes and I am going to pick up this cube spell. Are the half hexes also counted? I know half squares are counted. Any help at all would be appreciated.

If I use proper squares, the effects become effectively larger than they should be, so that doesn't seem right. For example, the 30-foot square below actually affects a width of 8 hexes (40 feet): • @PatrickvD That's answer material that belongs in an answer rather than the comments. If it feels like “but it doesn't literally answer the question”, consider that it is attempting to solve the problem — which is just what the answers are meant for (and comments aren't). (That kind of answer gets called a “frame challenge” around here; see our FAQ on that kind of answer for more: How do we handle a desire to challenge the frame of a question?) – SevenSidedDie Oct 19 '16 at 6:41
• @SevenSidedDie Thanks. Just posted an answer. Let me know if it needs to be reworded to because of the frame challenge thing (I'm not sure I get what the referenced question is saying completely.) – Patrick vD Oct 19 '16 at 7:01

There is advice/rules for this on page 251 of the DMG:

## Areas of Effect

[...] Choose an intersection of squares or hexes as the point of origin of an area of effect, then follow its rules as normal. If an area of effect is circular and covers at least half a square, it affects that square.

• So is my drawing correct for 10 20 30 feet? – Ilimax Oct 17 '16 at 0:44
• no, the quote says at least half – András Oct 17 '16 at 7:13
• @Ilimax Exactly half is also at least half. So I fail to see where András sees a mistake in the drawing from the question. – Philipp Oct 17 '16 at 8:25
• Hexas should be either fully colored, or completely white. The ones half colored now should be completely colored. – András Oct 17 '16 at 8:27
• "If an area of effect is circular", it says. This question is about a cube, not a circular shape. – kviiri Jan 24 '17 at 9:26

If you are open to a solution that isn't strictly to the rules, consider asking your DM to change it from a cube to a hexagon. It's quite simple if you use just choose a tile as the spell's center and then add one ring around it per 10ft of range. Example: 30ft cube would be 3 rings around the center, or 37 tiles.

It's a little too big when using a 7-tile hexagon for a 10 ft cube, and as you get bigger, it doesn't quite scale fast enough, but in my mind, the simplicity of the method outweighs inaccuracies like that. (Plus I doubt there are very many spells, if any, that are bigger than 30ft.) If you DM feels that the added space from a 10 ft cube is too big, then maybe have it be a 4-tile kite for those spells specifically.

I would answer this from the effect it has on the game. i.e. what is the number of squares (effectively creatures) that this spell affects? For squares, it's 36 squares (more for cube, but stay 2-D for now) So, pick a group of hexes, and count out 36 of them, keeping the shape roughly square-shaped. Done and done.

From there, you have two options, define the exact shape of the effect right then and there, and always use it exactly, or, allow the caster to subtly manipulate the 'leftover' hexes as he casts it.

In your specific example, choose either a row of 5+row of 6 +5+6+5+6 and you have a squarish shape of 33 hexes, and you can start a 7th row with the leftover 3 hexes, or you could define the shape as 6 rows of 6 and be more rectangular.