Military industrial organization modding (2024)

Military Industrial Organizations (MIOs) represent the applied research and development of your country.They boost your research in their area of focus and modify the stats of equipment produced with their aid.

Warning

Military Industrial Organizations and their policies are loaded only when creating a new game.it is not possible to inject new MIOs/policies into an ongoing game - for development / test runs, you must always create a new game.

You can freely modify what boni a trait grants, what icon to use or the localization. Adding traits is also possible, but removing existing traits can lead to errors.

Designing an MIO

What can you mod?

Fundamentally, MIO modding has four aspects you can modify:

• A fully independent Military Industrial Organization (Full MIO or Archetype)
• A MIO modification, based on another MIO, adding, removing or changing traits granted (Delta MIO)
• A Policy that can be applied to MIOs (typically after reaching Level 6+)
• AI Bonus Weights, which governs how the AI will prioritize boni granted by traits

Files and Folders

MIOs are defined in /Hearts of Iron IV/common/military_industrial_organization/organizations/, where you can place any number of MIOs in any number of txt files, encoded in UTF8 without a Byte Order Mark (BOM).For example, the game itself comes with one default "generic organization" file, containing the baseline templates, then one for each TAG that has alterations / extensions to that baseline.

Policies are defined in /Hearts of Iron IV/common/military_industrial_organization/policies/, again allowing any number of policies in any number of txt files, encoded in UTF8 without a Byte Order Mark (BOM).

Finally, AI Bonus Weights are defined in /Hearts of Iron IV/common/military_industrial_organization/ai_bonus_weights/

In all three directories of the game you can find a "documentation.info" text file describing some of the thoughts of the designers and some guidance.

The Error Log

While this is true for most aspects of modding, checking the error log has never been more critical than when modding MIOs:The simple fact that most errors impact the start of a game, are unfixable once it is running and that MIOs affect the game in the long run make it simple to waste a lot of time only to have to reset after all.

You can find the error.log text file in "%userprofile%\Documents\Paradox Interactive\Hearts of Iron IV\logs".Check it first after game start and browsing through the MIO menus (browsing the menus will trigger any errors associated with visibility filters).

Full MIO

Layout

<MIO Name> = {# Optional Localization Keyname = LOC_infernal_mio_tanksicon = GFX_keyequipment_type = { <equipment type> <equipment type> }research_categories = { <research type> <research type> }# Mandatory. In Country Scope.allowed = <condition># Optional. In MIO Scope. FROM = country.visible = <condition># Optional. In MIO Scope. FROM = country.available = <condition># Additional Events if desired#on_design_team_assigned_to_tech = { ... }#on_design_team_assigned_to_variant = { ... }#on_industrial_manufacturer_assigned = { ... }#on_tech_research_cancelled = { ... }#on_tech_research_completed = { ... }#on_industrial_manufacturer_unassigned = { ... }# Bonus to assigned researchresearch_bonus = 0.2# How many tasks can the MIO perform simultaneously?task_capacity = 999# Provide custom AI weights to help the AI choose the right MIO#ai_will_do = {#...#}# As many headers as desired.tree_header_text = {text = "Label1" # Either plain text or localization keyx = 0 # Just where on the header bar is the label placed. 0 = Leftmost, 9 = Rightmost}tree_header_text = {text = "Label2"x = 2}tree_header_text = {text = "Label3"x = 4}tree_header_text = {text = "LabelN"x = 8}initial_trait = <initial trait>trait = <trait>trait = <trait>trait = <trait># ... as many more as needed}

The Properties Explained

tree_header_text = { text = my_flavor_text_loc_key x = 1}

Trait Layout

trait = {token = upgrade_1 # mandatoryname = loc_key # optionalicon = GFX_key # optionalspecial_trait_background = yes # optional - default noparent = {traits = { parent traits }num_parents_needed = X}any_parent = { parent traits }all_parents = { parent traits}mutually_exclusive= { upgrade4 }position = { x=1 y=0 }relative_position_id = trait_tokenvisible = <condition>available = <condition> on_complete = <event>limit_to_equipment_type = { ... } # optionalequipment_bonus = <boni>production_bonus = <boni>organization_modifier = <boni>ai_will_do = <modifier> # optional}

Designing a trait

As we can see from the layout, designing a trait comes to a few key steps:

• Metadata
• Conditions
• Placement and relationship with other traits
• Boni granted
• AI (usually omitted)

From a metadata perspective, the "token" is a unique name within the current MIO. You can keep it simple without worrying about conflicts with other MIOs.A nice icon helps visually distinguish your trait. The easiest way to figure that one out is to search in "00_generic_organization.txt" for a trait that offers the same kind of boni as yours does and copy it from there.The name is if you want to select a custom localization key (by default it's "<mio_name>_<trait_token>").

Conditions are great to tie an MIO into the Focus tree of a nation. Use "available" for generic unlock conditions, while "visible" is great if the MIO is available in different situations. While for full TAG-based deltas, we would usually prefer going with a Delta MIO, consider the civil war situation in Spain, where you want to just replace one trait with another, depending on just which of the rebel factions - just define multiple traits on the same coordinates and switch between visibility.

Placement and relationship is where things easily get most complex. Fundamentally, you have a placement board of 10 slots wide and 5 high (you can go deeper, but then users have to scroll).This makes X go from 0 to 9 and y from 0 to 4.The parent settings determine the tree structure of your MIO. No parents means the trait can be picked right away - consider placing them at the top of your tree (y = 0) and build down from there. "any_parent" offers "any one among these" kind of parent logic, "all_parents" offers "every single one of them" kind of dependencies. The rarely seen plain "parent" node allows "at least X out of these" kinds of dependencies.Mutual exclusion, finally, is great for making the player pick between two or more options, where they can't just grab all of them. Be sure to place this condition on all traits in the mutual exclusion set, otherwise the player can first pick the trait with the exclusion and then afterwards the other one.

Boni granted - a list of those below in the Appendix - allow you to define the actual benefits (and trade-offs) the trait grants.These fall into three categories:

• Equipment: Effects that modify the equipment produced. This is what makes your tanks tougher, your ships faster and your fighters dodgier.
• Production: Effects that make production faster or cheaper, the line efficiency grow faster or to greater heights or conversion of equipment swifter.
• Organization: Effects that modify the MIO: Support more lines, greater research boni, faster growth, cheaper to assign, etc.

Finally, there's the AI, but best do not touch that unless you really want to.Trait prioritization is best handled through how the AI weighs boni (see chapter below on how to mod that).

Initial Trait

The initial trait you assign to a MIO differs in a few aspects:

• It has no position on the board
• It has no icon
• There is no decision to be made

In other words, most of the trait properties are not relevant to the initial trait. In fact, all properties are optional, but only these five matter at all:

• name: Localization key, overrides the default "<mio name>_initial_trait" key.
• limit_to_equipment_type: Narrows the equipment bonus of the initial trait to just a sub-set of its equipment types
• equipment_bonus: Boni granted to equipment
• production_bonus: Boni granted to the production of the related equipment
• organization_bonus: Boni granted to the MIO itself

Trait Properties Explained

token = gunnery_1

name = my_MIO_gunnery_1_Name

icon = GFX_generic_mio_trait_icon_hg_attack

special_trait_background = yes

parent = {traits = {gunnery_1 stealth_1 mines_1}num_parents_needed = 2}

any_parent = { gunnery_1 stealth_1 }

all_parents = { gunnery_1 stealth_1 }

mutually_exclusive = { heavy_guns_specialization }

position = { x = 0 y = 0 }

relative_position_id = gunnery_1

visible = {FROM = { has_country_flag = <flag name> }}

available = {FROM = { has_completed_focus = <focus name> }}

on_complete = {FROM = { set_country_flag = <flag name> }}

limit_to_equipment_type = { mio_cat_eq_all_light_tank }

equipment_bonus = {armor_value = -0.05defense =-0.05build_cost_ic = -0.03}

production_bonus = {production_efficiency_gain_factor = 0.15production_resource_need_factor = -0.15}

organization_modifier = {military_industrial_organization_research_bonus = 0.05}

ai_will_do = {base = 2modifier = {factor = 1.5date > 1937.1.1}}

Delta MIO

TODO: Write

Policies

name = loc_key

icon = GFX_mio_policy_my_policy

cost = 10

cooldown = 60

allowed = { OR = {has_mio_equipment_type = motorizedhas_mio_equipment_type = mechanized} }

visible = { has_mio_size > 3 }

available = { has_mio_size > 5}

equipment_bonus = {infantry_equipment = {soft_attack = 0.1}}

production_bonus = {infantry_equipment = {production_cost_factor = -0.1}}

organization_modifier = {military_industrial_organization_research_bonus = 0.1}

on_add = { ... }

on_remove = { ... }

ai_will_do = {...}

AI Bonus Weights

TODO: Write

Appendix: Boni

Equipment Boni

TODO: Write

Production Boni

All production boni apply to the production lines the MIO has been attached to.

Organization Boni

Organization Boni apply to the MIO globally and not to a specific equipment line / product.As such they cannot be constrained.

References