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Creating Fantasy Maps With GIMP: Caverns

I've been drawing maps for D&D since first playing the game in '78. Playing online requires digital maps, so I taught myself using GIMP.

Unpopulated caverns

Unpopulated caverns

Going Underground

Creating intricate fantasy maps is a time-consuming operation if you have a specific layout you are looking to replicate. If, by chance, you are willing to accept or work with a randomly created cavern map, then following these simple steps will create a finished map in minutes.

For this map creation exercise, you'll need some textured pictures of sand or rock. Different textures create different results. Beach sand pictures are great and easy to come by. Pictures of bricks or granite blocks can also be exciting textures. Searching online is another option. Look for images that are as large or larger than the finished map you wish to make, as this allows the definition to be crisp.

GIMP 2.8 is free and open-source. GNU Image Manipulation Program (GIMP) is a cross-platform image editor. We are using it to create fantasy maps.

Step-By-Step Cavern Creation

  1. Start a new file 900x900 at 600 dpi with a transparent background.
  2. Use Filters-Render-Clouds-Solid Noise... Detail set to ten X&Y set to three.
  3. Colors-Threshold... Adjust both black and white levels as you see fit.
  4. Use a solid paintbrush and black and white paints to edit the caves and passageways.
  5. Use File-Open as Layers... and open each of the two texture files. One for floors and one for walls.
  6. Make the B&W layer and select by color; black. Change to the lighter texture layer and Cut the selection. This will be the floor area.
  7. Make the dark layer next. Invert the selection, and cut. This is the wall section.
  8. On each of the layers make the opposite selection transparent. So on the walls layer make the selection for the floor area transparent.
  9. Select the Wall layer and the wall selection and use the Filters-Light and Shadow-Drop Shadow... set the shadow blur radius to 10 and the Opacity to 100.
  10. Optionally you can add a grid. Add a new layer (960x960 with a transparent background.) Filters-Render-Pattern-Grid... play with the size and opacity to achieve the results that work for you.
Finished maps with addons

Finished maps with addons

To finish off the map, you can add items like spider webs and water pools. Make the cavern unique and populate it with items as you need them.

You could also print out the map to use as a battle map or import it to your tabletop software of choice. Use the tabletop software to add your various tricks, traps, and additions as well with monsters.

Another example.

Another example.