Wiki

effect · load_oob

Definition

  • Supported scope:COUNTRY
  • Supported target:none

Description

Immediately loads an Order of Battle (OOB) file.

Example:
load_oob = "ENG_1936"

Hands-On Notes

Hands-on notes are AI-generated and checked against the vanilla command vocabulary — treat them as a starting point, not authoritative reference. The definition above is the game's own documentation.

Hands-On Usage

load_oob is commonly used in historical scenario mods to reload a preset army composition for a nation under specific trigger conditions (such as when the player completes a focus tree or reaches a historical milestone), and can also be used in civil war events to instantly spawn military units for rebel factions. Note that OOB files must be located in the history/units/ directory and the filename must match the parameter exactly.

# Load the 1939 wartime composition immediately after completing a focus
complete_national_focus = SOV_war_preparations
hidden_effect = {
    load_oob = "SOV_1939_mobilization"
}

Synergy

  • [delete_units](/wiki/effect/delete_units): Delete old units before loading a new OOB to avoid duplicate units and redundancy when the new composition overlaps with existing forces.
  • [add_manpower](/wiki/effect/add_manpower): Spawning units from OOB files consumes manpower; replenishing manpower beforehand ensures units are generated completely without becoming understrength.
  • [country_event](/wiki/effect/country_event): Commonly used as an effect in event options to load the corresponding unit composition immediately after the player makes a choice, creating a smoother narrative experience when paired with story events.
  • [has_completed_focus](/wiki/trigger/has_completed_focus): Serves as a precondition trigger for load_oob to ensure unit loading only executes after completing a specific focus, preventing premature or duplicate triggers.

Common Pitfalls

  1. Filename case mismatch: HOI4 is case-sensitive on Linux/Mac environments. If the script uses "ENG_1936" but the actual filename is "eng_1936.txt", the game will fail silently without reporting an error, causing units to never appear.
  2. Loading without clearing old units: Calling load_oob directly on a nation that already has many units will not replace existing units but stack new ones on top, resulting in an explosion of division-level units that severely impacts AI behavior and game performance.