Tips for drawing natural caves on a grid mat

[No brains]

I'm running an adventure that takes place in irregularly shaped caves and I want to run the encounter in it on a battle grid because I love pain apparently.

Does anyone have any tips for drawing 'naturally' shaped caves on a grid? I need ways to remember what crannies go where. I would just forget it and just go for wildly chaotic shapes improvised when I start drawing, but this cave also has to fit together on the macro scale. I don't want walls crossing into other rooms or the like.

One idea I had was to break down the caves into large boxes and then add to the boxes. Like room 7 is a 4x7 and has three 1x3 protrusions on some walls. Does that help anyone?

[a_flemish_guy]

my tip would be: don't try to invent the hot water again, same with castle levels

there are so many videogames who have caves as part of their levels and you can easily find maps of those on-line

not only do you have a readilly made cave map but they come in all sizes and most importantly are already optimised for playing games (if you'd copy an all natural map then you'd have a lot of dead-ends with nothing there)

[Segev]

I'd just draw the cave, then superimpose the grid. Or start with the grid, and draw the cave out, only caring about the grid for size reference. Decide whether you want partial squares to be always occupiable, occupiable only if 50% of them are outside the wall, or never occupiable, and let well enough alone. Remember that the grid is an abstraction, anyway, and that a personal 5 ft. (or bigger) space is more about how much room you need to fight effectively than anything else.

[Mastikator]

I found a cave generator that might help
https://donjon.bin.sh/fantasy/dungeon/cavern.cgi

Another option is to treat it like an underground river that went dry, it's not really a cave but an underground ravine but it gets the job done.

[No brains]

Perhaps I should have been more clear: I meant physically drawing a cave onto a grid mat by hand with dry erase markers. The adventure I am doing has irregular caves I need to copy, but the process is long and involved.

I think subdividing the rooms into squares relative to each other and then just winging the details of the cave may be adequate. Sure a crevice being 20ft deep or 25 ft deep may make a difference, but if my players face fights competently, it will be unlikely.

[Rakaydos]

Is there a particular reason you go for a square-grid, instead of flipping over your mat and doing it on the Hex-grid side?

[Imbalance]

Does your reference illustrate the cave on a grid? Can't you simply transpose it 1-for-1?

[Jay R]

You don't have to make the walls exact, as long as each open square is open, and each stone square is stone.

So go through and put a small brown mark in the middle of each square that is stone. Then draw an irregular line around them.

[Segev]

Perhaps I should have been more clear: I meant physically drawing a cave onto a grid mat by hand with dry erase markers. The adventure I am doing has irregular caves I need to copy, but the process is long and involved.

I think subdividing the rooms into squares relative to each other and then just winging the details of the cave may be adequate. Sure a crevice being 20ft deep or 25 ft deep may make a difference, but if my players face fights competently, it will be unlikely.

Ah, you're trying to transpose one.

The solution I've used is to try to blow it up to one-square-inch size and just print it out, but that can be time-consuming, expensive, and, depending on the quality of the map image, unsatisfying.

Yeah, you don't need to be precise in transposing it. In fact, if you're not, and you make the PCs make their own map for their own reference, you can draw it as needed, erase, then draw the next bit. Any discrepancies can be attributed to their failure to keep a perfect 3D rendering in their heads. (If you have a PC who can, well, give him the real map eventually after he's gotten through it.)

Just get the major dimensions correct - the right number of squares in each row and column, even give or take a square, is sufficient.

[Elysiume]

The last time I did caves on a grid, the source map I was using wasn't even gridded. I used a single element with a set size as a point of reference, overlaid a grid in gimp, then resized things a little bit anyway. What I'm getting at is seconding what Segev said: the exact size/shape of each room isn't hugely important. As long as it's close and fits what it needs to fit, the players aren't going to know the difference.

[Mordaedil]

For a quick and easy simpletons way of doing it, just mark off squares by how much space a character can fit into it and slash out the rest. It is pointless to have squares that allow less than a foot of a character inside of it, just mark off where they can fit in fully or squeeze in (half squares) consider the rest "blocked". Put a single line in areas with difficult terrain, but point out it is because of stalagmites or ponds as necessary.