Modding guidelines

For players

See mod list

For modders

Creating mod

To make your own mod you need to create subdirectory in /Mods/ with name that will be used as identifier for your mod.

Main mod is file called mod.json and should be placed into main folder of your mod, e.g. Mods/myMod/mod.json

All content of your mod should go into Content directory, e.g. Mods/myMod/Content/. In future it will be possible to replace this directory with single .zip archive.

Example of how directory structure of your mod may look like:

Mods/
     myMod/
           mod.json
           Content/
                    data/    - unorganized files, mostly bitmap images (.bmp, .png, .pcx)
                    config/  - json configuration files
                    maps/    - h3m maps added or modified by mod
                    music/   - music files. Mp3 is fully supported, ogg may be added if needed
                    sounds/  - sound files, in wav format.
                    sprites/ - animation, image sets (H3 .def files or VCMI .json files)
                    video/   - video files, .bik or .smk

Creating mod file

All VCMI configuration files use JSON format so you may want to familiarize yourself with it first.

Mod.json is main file in your mod and must be present in any mod. This file contains basic description of your mod, dependencies or conflicting mods (if present), list of new content and so on.

Minimalistic version of this file:

{
    "name" : "My test mod",
    "description" : "My test mod that add a lot of useless stuff into the game"
}

See Mod file Format for its full description.

Overriding graphical files from Heroes III

Any graphical replacer mods fall under this category. In VCMI directory <mod name>/Content acts as mod-specific game root directory. So for example file <mod name>/Content/Data/AISHIELD.PNG will replace file with same name from H3Bitmap.lod game archive.

Any other files can be replaced in exactly same way.

Note that replacing files from archives requires placing them into specific location:

H3Bitmap.lod -> Data
H3Sprite.lod -> Sprites
Heroes3.snd  -> Sounds
Video.vid    -> Video

This includes archives added by expansions (e.g. H3ab_bmp.lod uses same rules as H3Bitmap.lod)

Replacing .def animation files

Heroes III uses custom format for storing animation: def files. These files are used to store all in-game animations as well as for some GUI elements like buttons and for icon sets.

These files can be replaced by another def file but in some cases original format can't be used. This includes but not limited to:

• Replacing one (or several) icons in set
• Replacing animation with fully-colored 32-bit images

In VCMI these animation files can also be replaced by json description of their content. See Animation Format for full description of this format.

Example: replacing single icon

{
	// List of replaced images
	"images" : 
	[	  // Index of replaced frame
		{ "frame" : 0, "file" : "HPS000KN.bmp"} 
		               //name of file that will be used as replacement
	]
}

"High resolution main menu" mod can be used as example of file replacer mod.

Mod with new content: Artifact

TODO

Mod with new content: Creature

TODO

Custom filesystem format. Porting Era Mod to VCMI

TODO

Modding related articles

Main articles
Modding changelog	Modding guidelines	How to create a town mod	Mod Handler

Formats
	Mod file Format
Town Format	Creature Format	Hero Classes Format
Artifact Format	Animation Format	Hero Format
Bonus Format	Object Format	Spell Format

Work-in-progress formats
Building bonuses		Map format
	Bonus Type Format	Random map template

Outdated pages
	Mod system proposal