This file sorts units into different armor classes. Weapons can deal different amount of damage to different armor classes.

Location

armordefs.lua is a file in the Gamedata/ directory of a Spring Game.

Source

The engine source code which parses the data from this file is viewable here:

rts/Sim/Misc/DamageArrayHandler.cpp

Details

By default a damage class named "default" exists and every unit is in it. So if all your weapons only deal "default" damage then this file is not needed.

Example

local armorDefs = {
	tanks = {
		"supertank",
		"megatank",
	},

	infantry = {
		"dude",
	},
}

--NOTE: only needed for <95.0 (before engine was expecting a cryptic format)
if not(Game) or not(Game.version) then
  for categoryName, categoryTable in pairs(armorDefs) do
    local t = {}
    for _, unitName in pairs(categoryTable) do
      t[unitName] = 1
    end
    armorDefs[categoryName] = t
  end
end

return armorDefs

Weapon Example

Goes with above example, a weapon that deals 60 damage to infantry but only 5 damage to tanks:

...
damage = {
	infantry = 60,
	tanks = 5,
},
...

Shields

In engine versions =< 96.0 the damage dealt to shields is the weapon's default value. This changed in v98.0

Putting a shield into an armor class is analogical to units, ie. the armorDefs entry is its weaponDef name:

armorDefs = {
  units = { "shieldbot" },
  shields = { "shieldbot_shield" }
}

Then in some damage table:

damage = {
  default = 123,
  units = 456,
  shields = 789
}

Links to more Examples

zero-K
Contains scripting to take into account various things like EMP damage.

Tutorial Game
Uses default damage class, except for one unit that is "armored."

MechCommander: Legacy
Automatically assigns units to an armor class based on UnitDef tags and custom params.