Seeking Help to Develop a Mod: Adjusting Commander Collision Properties

Raysor

Hello everyone,

I’m reaching out to ask for help with a mod I’m currently developing for Supreme Commander: Forged Alliance. The goal of this mod is to adjust the collision properties of the commanders for each faction.

The main idea behind this change is to address a specific frustration I’ve encountered during gameplay: the commander often gets overwhelmed by units in the base, making it difficult to move effectively. By tweaking the collision properties, I hope to create a smoother experience where the commander can navigate better without feeling bullied by every single unit around.

This is my first time tackling a mod of this kind, so I’m looking for guidance on how to approach these changes and ensure they integrate naturally into the game. Any advice, pointers, or resources you can share would be greatly appreciated, thank you!

Uveso

First of all, press [CTRL] + [SHIFT] + [ALT] + C to display the hitboxes in-game.

You have two options to change the hitboxes of a unit.

First of all, you can copy the entire blueprint into your mod and modify the relevant lines, such as SizeX, SizeY, and SizeZ.
However, this approach has the disadvantage that you will need to update the blueprints with every ACU patch.

A better option is to use a ModBlueprints function in Blueprints.lua.
Here’s an example of a ModBlueprints function:
https://github.com/Uveso/AI-Uveso/blob/master/hook/lua/system/Blueprints.lua

a function to change the hitbox could look like this:

    -- save the actual ModBlueprints into OldModBlueprints
    local OldModBlueprints = ModBlueprints
    -- by creating a funktion with the same name we overwrite the original ModBlueprints
    function ModBlueprints(all_blueprints)
        -- execute the original function to not break other mods
        OldModBlueprints(all_blueprints)
        -- loop over all blueprints
        for id,bp in all_blueprints.Unit do
            check if we have an commander
            if table.find(bp.Categories, 'COMMANDER') then
                change the hitbox
                bp.SizeX = 1
                bp.SizeY = 1
                bp.SizeZ = 1
            end
        end
    end

i hope this helps a bit.

Caliber

@Uveso

I have been playing around with my own mods for a few years now and I never knew about being able to display the hitbox like this thats sooooo useful, are there any more interesing functions like this?

Raysor

@Uveso
Thank you so much for your help, I really appreciate it! I just have one question: if we change the hitbox, will it also affect the interaction with projectiles? I’m concerned it might cause issues and make the commander untouchable, which I definitely want to avoid.

Uveso

The hitbox also applies to projectiles.
I encountered an issue in Black Ops where the hitbox was too small:
https://github.com/Uveso/BlackOpsFAF-ACUs/pull/7
Make the hitbox the same size for every ACU to avoid complaints. Also, ensure it's not too small; otherwise, the commander can only be hit with area damage.

Oh, and when you're in the game, press [F1] to open the key bindings. Under the 'Debug' section, you can see all functions and their assigned keys.

Nomander

You can hack around the issue with projectiles by setting the ACU's hitbox to very small so that it paths around units a bit better, and then creating an entity attached to the commander with a hitbox. Then you can override the new entity's OnCollisionCheck, OnCollisionCheckWeapon, and OnDamage functions with the ACU's versions.

There is an example of creating an entity attached to a unit in the Aeon T2 Torpedo Launcher script. I don't have an example of an entity with a hitbox passing damage to the base unit, although I know it's possible since giving props projectile collision was an experiment we did.