BuildingUnits

Making new units is fairly easy. Unit configuration files are plain text files that you can edit with any editor such as Notepad, TextEdit, gedit, pico, vi, emacs, etc. You will need to become familiar with WML in order to make a new unit. This page contains a more in-depth discussion of Unit WML syntax and will walk you through the creation of a new unit and discuss how you can use it in-game.

Recommended procedure

The easiest way to make a new unit is to copy and paste an existing unit, then modify it. Navigate to the game's data/units or data/core/units directory (see EditingWesnoth) and copy any unit. When you are editing the unit, pay attention to the property keys. If you forget to modify each key (for example, the unique id key), problems may arise, varying for minor issues such as lack of features on the unit, to game refusing to load the unit file, or, in the worst case, crashing the game. For complete reference on unit properties see UnitTypeWML.

Most of a unit's properties are self-explanatory to anyone who has played Battle for Wesnoth for very long, and the tags in the WML files are brief but descriptive. It is recommended that you try editing by yourself before consulting the guide. Otherwise, you may find the guide confusing.

Using your new unit

Any unit in the game's existing data/units/*/ directories (you can't just add a new directory to data/units/) or userdata/data/ will be recognized by the game. If you only want to use it once or twice as a special unit, that's all you need to do. However, just because you made a new unit does NOT mean that it can be recruited. Each scenario and multiplayer era has a specific recruit list. If your unit is not on the list, you can't recruit it. This means you need to modify the recruit= key in the appropriate configuration file. BuildingMultiplayer describes different ways you do this for multiplayer. To add a unit to a campaign, read about scenarios, sides, and recruit lists in BuildingScenarios.

Distributing your unit

If you made a single unit, post it on the forum. If you made a whole group of units, you can make them into a multiplayer faction or you can upload a unit pack.

If you want to make a faction, follow the instructions in the BuildingFactions article. You should create a new era and add your units as one of the factions. You will not be able to add your units to any era that ships with the game.

If you want to make a unit pack, the procedure is easier. Unit packs are distributed for campaign writers who want to use your units in their campaigns/eras. They download your unit pack and copy/paste the units and images into their campaign/era. The era we'll use as an example will be called MyUnitPack.

Navigate to the userdata/data/add-ons directory. Create a new directory called MyUnitPack and navigate to it. Everything from now on will occur relative to here.
Create a text file called _main.cfg. Add the following lines:

#		#define USE_MYUNITS		#<- replace MYUNITS with something descriptive
#		#enddef
#		#ifdef USE_MYUNITS		#<- replace MYUNITS with something descriptive
#		{~add-ons/MyUnitPack/MyUnitPack.cfg}
#		#endif

These lines are commented out (with the #). That way when the unit pack ships it won't affect the game. If someone wants the game to be able to see these units, he can uncomment those lines and it will work. However, this usually causes problems in multiplayer (you will be using units no one else has), but it can be fun for campaigns.
NOTE: the commenting/uncommenting trick will only work if the units branch off of an existing unit. Custom L1 units will NOT show up in game automatically without editing another configuration file somewhere (scenario config file or multiplayer.cfg)

Create another text file called _server.pbl. (See PblWML for more details about *.pbl files.) Add the following lines to it:

author="your name"
icon="any image file in the game's ./images directory"
version="1.0"
title="My Awesome Unit Pack"
description="New race of lizard men."
type="faction"
email="you@example.com"

The email above can be left out, but is highly recommended in case of problems. It will not be made public.
Create two subdirectories: units and images. Place your unit cfg files and artwork into those subdirectories
Create a text file called MyUnitPack.cfg (if you choose a different name, you will have to replace MyUnitPack.cfg in _main.cfg as well). Add the following lines:

[binary_path]
path=data/add-ons/MyUnitPack
[/binary_path]
[+units]
{~add-ons/MyUnitPack/units}
[/units]

You should be ready to distribute your unit pack on the campaign server now
PLEASE change the names to something unique before you publish

Unit WML discussion

As of 1.6, unit definitions are enclosed in [unit_type] tags.

This section only provides some tips and pointers in making a unit. Feel free to add pointers of your own. For the full, current, complete WML reference on what to put in your [unit], see and frequently revisit The Unit WML reference page.

The first attribute of a unit is the id attribute, which is a unique identifier for the unit. As value of the type attribute for these units, the id key is used. (See BuildingScenarios).
When referencing the unit in a type key, the id must be reproduced verbatim, without typos, and in a case-sensitive manner. If you don't do this, the key won't work. If you can't recruit in a scenario, it's probably because you have a typo in one of the unit ids and the recruit key was invalidated.
It also has a name key, which is the (translatable) name of the unit, and is displayed on the Status Table when a unit of this type is selected. It does not need to be unique (but it helps).
Do not set movement to 0. It creates weird infinite movement behavior. This might be fixed in the future. For now, to make an immobile unit, set movement to 1 and use [movement_costs] to make it unable to move onto any terrain.

See BuildingScenariosIntermediate for more information on attacks.

BuildingUnits

Contents

Recommended procedure

Using your new unit

Distributing your unit

Unit WML discussion

See Also