How to explore a dungon with OnTheFlyBattlemaps

I was asked what tool I would use to run a dungeon crawl in PBP, and my answer is OnTheFlyBattlemaps

I start by finding getting my image of a full dungeon. This is a random one off the internet.


I select the OtFBM and get this standart bit of code

[map]https://otfbm.io

--Map size, cell size, and panning
/26x14/@c60/b5:10x6

--Tokens
/f7-Alice
/h8-Bob

--Background image
?bg=https://i.imgur.com/jIpAjkT.jpg
[/map]

I exchange the background image with my own map url

/?bg=https://i.pinimg.com/originals/e1/57/61/e157610adc4fe2b1807da129be9d8a8a.jpg

I see that the map already has grids so I make the OtFBM grid invisible

/@n

And by looking at the image, in an imageeditor like MSpaint, I see that a square is about 70 pixel

/@c70

I set a grid size of 50x50

/50x50

My current code produces this image where the map coordinates maches the grids, or atleast close enough. :) It does not have to be perfect to get the message across

[map]https://otfbm.io
/50x50
/@c70
/@n
/?bg=https://i.pinimg.com/originals/e1/57/61/e157610adc4fe2b1807da129be9d8a8a.jpg
[/map]

Now I'm showing the full map. I have two options. I can zoom into an area or I can can introduce a fog of war. I will do both.
Fog of war only reveals the map area that I span. /*f tells it that it is fog of war. r24 my top left cornor and af50 is the bottom right cornor of the map /*fr24af50. As my players explore more and more, I can reveal more and more ares of the map with multiple revals

[map]https://otfbm.io/50x50/@c70/@n
 /*fr24af50
 /*fm30r34

/?bg=https://i.pinimg.com/originals/e1/57/61/e157610adc4fe2b1807da129be9d8a8a.jpg
[/map]

Zooming is applyed by marking a upper left cornor of the square of your zoom and then the dimention of your zoom box. In this case m23 is my start and it should be 22x27 wide

[map]https://otfbm.io/50x50/@c70/@n
/m23:22x27

 /*fr24af50
 /*fm30r34
/?bg=https://i.pinimg.com/originals/e1/57/61/e157610adc4fe2b1807da129be9d8a8a.jpg
[/map]

---

And there we have it. A map of a dungeon that the players can explore and you as a GM can maintain with realative ease. There offcorse more options to add overlays, spelleffect, character tokens and much much more and have been descripted in the documentation or by Qralloq here

Thanks for posting this.

Zooming in
Instead of the /m23:22x27 syntax, it can be easier to refer to the top and bottom coordinates: /m23:ah49

Fog of war transparency
As a DM, working on fog of war can be awkward.
Add /@w50 to make the areas hidden by FoW partially visible, then comment it out when you've finished by prefixing that @w50 with --Generating tokens
By adding the OtFBM sheet to your game, you can quickly generate an OtFBM token from an image URL.
1) Select the helper sheet
2) Paste the image URL and then Get token (the token code will open in a new tab)