D&D 5E How Do I Figure Out A Room Size On A Diagonal Room On A Grid Map?

[O-Castitatis-Lilium]

Hello!

So, I have a question. I draw my maps out for my players because...well I love to do it. I am trying to recreate this map that's really small on a page, but it has a couple diagonal rooms. Now, usually the rooms have sizes for them...but reading through the module and the descriptions of the rooms; they don't have a size on them. I can usually make the rooms with the given size...but I don't have that, so now, I'm trying to figure out how to get the size, knowing that each square is 5 ft. I tried counting them out..but they are slightly misaligned on the grid that they come on. OH! the map I'm looking at is the one for the Doomvault in Tales From The Yawning Portal. I have plans for it lol. Any and all help is greatly appreciated.

 

[SableWyvern]

If a square is five feet, it is roughly 7.5 feet from corner to corner. Not sure if that helps or not.

If the squares are offset by a full half square (not sure what you mean by misaligned), then what you have is actually equivalent to a hex grid.

 

[Paul Farquhar]

it’s a common shorthand to treat diagonals as one and a half grid squares long. A mathematician will till you they are actually root two times - 1.41.

 

[UngainlyTitan]

Now that you have got the technically correct answers, I would add, don't sweat it too much. The exact size of the room does not matter. Unless the characters are going through the place with surveying equipment and are noting and carefully mapping as they go along, they don't know the exact size of the place either.
The grid is fun and useful in game but gives precision that one does not have normally. So, close enough is good enough.
After all, think of a place that you frequently visit, like a shopping mall. How big is it? what is the area of each of the rooms?

 

[Staffan]

Also, if the whole room is diagonal and you're using a battlemap, you might want to align the grid within that room to the actual room. The grid is supposed to be an aid to movement and positioning after all, not a god-given coordinate system.

Edit: I'm thinking of a room like this:

That would likely work better with the grid aligned to the walls of the room, not the overall dungeon map.

 

[Wofano Wotanto]

I'm stating the obvious here, but if you take a ruler, measure the width and length of the room on the tiny map, and then use those measurements to just draw the room in whatever larger scale you're using for a play mate you should be golden. Hardest part is probably figuring out how much you need to upscale from the reduced tiny-map image if they didn't tell you in the module, but even that shouldn't be much of a hassle.

If you're having trouble aligning the diagonal rooms you could just draw them on a separate piece of paper, cut them out, and use them as a tool to trace around. Grade school art class stuff, but it works fine in analog.

 

[aco175]

This is the thing you are looking at? Yeah, I would not worry that perfection would get in the way of fun.

Another thing I learned on a grid is to make the diagonal in the middle of the side on the square instead of corner to corner. This creates one square that is about 80% and another next to it about 20%. It is better for moving minis and knowing if they can be in a square or not. More like the 2nd in the image below. I have never tried the 3rd, but I like it as well.

 

[Wofano Wotanto]

This is the thing you are looking at? Yeah, I would not worry that perfection would get in the way of fun.

Having seen the map now, agreed. With all those different room shapes and angles I'd be tempted to just skip the grid altogether and use a tape measure or ruler to measure distances and AoE effects and whatnot. There's times when grids are a hindrance rather than a help.

 

[UngeheuerLich]

Also, if the whole room is diagonal and you're using a battlemap, you might want to align the grid within that room to the actual room. The grid is supposed to be an aid to movement and positioning after all, not a god-given coordinate system.

Edit: I'm thinking of a room like this:
View attachment 349831

That would likely work better with the grid aligned to the walls of the room, not the overall dungeon map.

And then I had a 4e group breaking apart because I positioned a skeleton in the middle of a 2 squares wide corridor.

 

[cbwjm]

And then I had a 4e group breaking apart because I positioned a skeleton in the middle of a 2 squares wide corridor.

One of the issues with a grid, is that people will often feel like everything should conform to it in regards to movement, range, etc.