Image to h3m (v0.0.0)| Convert images into maps for Heroes 3

This tool allows you to convert images into terrain in downloadable, editable h3m files for Heroes of Might and Magic 3. Use the settings in the sidebar to map the image's color clusters to terrain types and more. (Note: Map outputs are in Horn of the Abyss format by default. Disable HotA in the sidebar for Shadow of Death compatibility.)

📥 Input

Input type

🖼️ Image 🖼️ Image + 📜 existing map 🗺️ Geographic location (beta) 🧩 Maze

Source image(s)

Overworld

Underground

Two-level map

Source map

Note: Source maps with terrain that overrides the usual editor restrictions will likely result in outputs that cause the editor and game to crash. For the safest results, upload maps that were not made using special editing techniques.

Common maps folder:

Copy

Hemispheres

Two-level map

Preserve aspect ratio with crop-to-fill

Unchecked = stretch to map size.

Horn of the Abyss

⛰️ Terrain

Map size S (36×36) M (72×72) L (108×108) XL (144×144) H (180×180) XH (216×216) G (252×252)

Color clusters 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Grid size

Note: Water and rock are disabled for existing map inputs. Existing water and rock from the source map are preserved.

Use separate palettes for overworld and underground

Region mapping

Choose which Heroes III terrain each real-world region type should be converted to.

Maze palette

Choose which Heroes III terrain to use for maze paths and walls.

Generate map

📦 Export settings

Map name

Encode source image(s)

Checked = map will include inert events containing the source image(s) in base64.

Note: When you export a map with an encoded image, you can then upload that map as a source image, and the tool will use the image's base64 as the image input. You can also convert the base64 back into an image using online tools.

Compress encoded image(s) to map size

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Preview

Source

Overworld

Underground

Uploaded map terrain

Overworld

Underground

Center
0.00, 0.00

Selection
—

Generate map

Map output

Overworld

Underground

Download map (.h3m)

Load an image to begin.