Is there a way to blend hex and square grid for battle maps?

Question

I'm new to hexes and not too experienced with map-making in general, and I want to expand my understanding of them. While I was figuring out how radiuses would work for things like spells on a hex map, I was a little stumped when it came to cubes and squares. I have a few questions about getting squares out of hexes and blending the two types of maps.

Is it possible to mark squares on a hex map with half hexes? Or could I layer a square grid over as a measure reference?

Would it be possible to blend the two types of grids? Like hexes used for inside structures & squares for outside? (Not like overworld maps).

Answer 1

Not with a grid based on regular hexagons

Is it possible to mark squares on a hex map with half hexes?

No because the ratio between the length of the short diagonals and long diagonals (that is: horizontal and vertical distance) in a regular hexagon is irrational. That means no matter how small you dice them, you can never use them to approximate a square.

Or could I layer a square grid over as a measure reference?

No because hex grids and square grids in a tabletop game have different anisotropy. This may be system specific, but in DnD5E on a square grid it is very efficient to walk in multiples of a 45° angle but not very efficient to walk in multiples a 90° angle. On a hex grid, you can only walk in multiples of 60° angles and they are all equally efficient. It gets more complicated if you go more than 1 "step".

Would it be possible to blend the two types of grids? Like hexes used for inside structures & squares for outside?

Technically, no because for the same two reasons above, they will never align properly (at least not at the corners). However, you can of course just do it anyways and accept that the solution isn't perfect.

An irregular hexagon grid can help

If you "smush" the hexagon grid such that the long diagonals in the 90° angle are the same length as the short diagonals in the 0° angle, then they align well with a square grid. You will be able to neatly overlay the grids, compare horizontal and vertical distances, and neatly align grid transitions. It still won't help you with comparing distances in any other direction (e.g. spell ranges) due to the anisotropy problem, though.

Answer 2

Long, long ago, there was a grid format of squares that worked like hexagons, in terms of each square space having six neighbors (they weren't all the same center-to-center distance, however).

This was called "offset square" grid and consisted of alternating rows of squares offset by half a square width. Unfortunately, even this won't overlay on a hex grid and keep everything lined up, because of the unequal center distances on the diagonals, but it might be possible to use this instead of a hex grid, since it gives the same movement and you can calculate radius and so forth by counting center to center as you would with hexes.

With a little trigonometry, it ought to be possible to "squash" the non-offsetting dimension of the squares to give equal center to center distances as well, which would then allow the offset squares grid to either overlay a hex grid, or work in its place even if you sometimes need to measure with a stick, template, or tape measure.