Add a new gun¶

A gun is two assets. A Data Asset holds every number and every asset reference. A child of BP_WeaponBase holds the mesh and the points where things spawn from it. When both exist the gun can be equipped, aimed, fired, reloaded, holstered, refilled and upgraded, and you never open a graph to get there.

If you have not read How guns work in this template, start there.

The two folders you will work in:

Data Assets: Content/TheLastTemplate/Blueprints/DataAssets/Weapons/Childs/
Weapon classes: Content/TheLastTemplate/Blueprints/Weapons/Childs/

Before you start¶

You need a skeletal mesh for the gun. That is the only thing the template cannot give you.

Everything else can be borrowed from a gun that already ships while you get the weapon working, and replaced later:

Animations. Two full sets ship, in Content/TheLastTemplate/Animations/Montages/Characters/Pistol/ and .../Shotgun/. Point your gun at one of them and it will animate on day one.
Sounds. Content/TheLastTemplate/Audios/Weapons/.
Muzzle flash. NS_Muzzle_Pistol and NS_Muzzle_Shotgun in Content/TheLastTemplate/Niagara/Muzzle/.
Crosshair. MI_CrosshairPistol, MI_CrosshairShotgun and MI_CrosshairRifle in Content/TheLastTemplate/Materials/Widgets/Crosshair/. The rifle one ships unused, so an automatic weapon already has a crosshair waiting for it.
Camera shake. CS_ShootCamera and CS_ShootCamera_Heavy in Content/TheLastTemplate/Blueprints/Misc/CameraShakes/.

Pick the shipped gun closest to yours and copy from it. A pistol-like weapon copies DA_Pistol_01, a long gun copies DA_Shotgun_01.

Step 1, make the Data Asset¶

In Content/TheLastTemplate/Blueprints/DataAssets/Weapons/Childs/, right click DA_Pistol_01 (or DA_Shotgun_01) and choose Duplicate.
Name it after your gun, for example DA_Rifle_01.
Open it. Every field is already filled with a working value, so from here you are replacing, not filling in blanks.

Set the identity fields first:

Field	What it does
`Weapon Display Name`	The gun's name in game. `DA_Pistol_01` ships `Semi-Auto Pistol`.
`Weapon Description`	One line of text describing the gun.
`Weapon Icon`	The silhouette drawn in the weapon wheel and on the ammo counter. Shipped icons live in `Content/TheLastTemplate/Textures/Widgets/Icons/`, for example `T_PistolMaskWhite`.
`Weapon Icon Scale`	Fits your icon in its slot. `0.65, 0.65` for the pistol, `0.99, 0.55` for the wider shotgun.
`Clip Size`	Rounds in a full magazine. 16 on the pistol, 8 on the shotgun.
`Radial Slot Row`	Which row of the weapon wheel the gun sits on. The shotgun is on row 1, the pistol on row 2.
`Weapon Type Socket`	The slot the player carries the gun in, `Primary` or `Secondary`. The shotgun is `Primary`, the pistol is `Secondary`.
`Weapon Overlay`	The upper body pose the character holds.

Everything about rate of fire, spread, recoil, damage and aiming is in this same Data Asset and is covered in Change how a gun feels to shoot. The fields that only matter when an AI is holding the gun are covered in Give an AI a gun and upgrades.

Note

Weapon Overlay is a fixed list: Base, Shotgun, Pistol, Throw, Combat, Zombie. Only Pistol and Shotgun are gun poses. Pick whichever of the two your weapon is closest to. A third gun pose means new animation work in the character's animation Blueprint, which is outside what a Details panel can do.

Step 2, fill the animation fields¶

Six montage fields. Three play on the character, three play on the gun itself.

Field	Plays on	Shipped in `DA_Pistol_01`
`Character Fire Animation`	Character	`AM_Character_Pistol_Fire`
`Character Empty Animation`	Character	`AM_Character_Pistol_EmptyFire`
`Character Reload Animation`	Character	`AM_Character_Pistol_Reload`
`Character Equip Animation`	Character	empty
`Weapon Fire Animation`	The gun	`AM_Pistol_Fire`
`Weapon Empty Animation`	The gun	empty
`Weapon Reload Animation`	The gun	empty

The weapon montages are for a gun whose own mesh moves, a slide cycling or a pump racking. DA_Shotgun_01 leaves all three weapon fields empty and drives its pump from the character montage instead. Leaving a field empty is allowed and simply means nothing plays.

The character montages must be built for the same skeleton as your character. If you are reusing the shipped pistol or shotgun set, they already are.

Step 3, sounds and effects¶

Field	What it does	Shipped in `DA_Pistol_01`
`Weapon Fire Sound`	The shot	`SC_Pistol_Fire`
`Empty Sound`	The click when the magazine is empty	`SC_DryFire`
`Magazine Drop Sound`	The magazine hitting the ground	empty
`Muzzle Flash Effect`	Niagara system spawned at the muzzle	`NS_Muzzle_Pistol`
`Muzzle Flash Scale`	Scales that system to your gun	`2, 2, 2` (the shotgun uses `3, 3, 3`)
`Crosshair Material`	The crosshair drawn while aiming	`MI_CrosshairPistol`
`Camera Shake`	The kick on the camera per shot	`CS_ShootCamera`

Ejected Shell and Eject Magazine Class decide what physically leaves the gun. Both are actor classes, and both have a base you can duplicate:

shells: BP_EjectAmmoBase in Content/TheLastTemplate/Blueprints/Weapons/Ejects/, with BP_Eject_Ammo_Pistol_01 and BP_Eject_Ammo_Shotgun_01 as worked examples
magazines: BP_EjectMagazineBase, with BP_Eject_Magazine_Pistol_01

Duplicate one, swap its mesh, and point your Data Asset at it. DA_Shotgun_01 leaves Eject Magazine Class empty because a pump shotgun has no magazine to drop.

Step 4, sockets¶

Five socket names are typed into the Data Asset as text. If a name does not match a socket that exists, that attachment silently goes to the wrong place or does not happen.

Field	What it points at	Pistol	Shotgun
`Weapon Grip Socket R`	Where the gun sits in the right hand while it is drawn	`PistolHandRSocket`	`ShotgunHandRSocket`
`Left Hand Magazine Socket`	Where the fresh magazine or shell is held during the reload	`InsertMunitionPistolSocket`	`InsertMunitionShotgunSocket`
`Ejected Magazine Socket`	Where the dropped magazine leaves from	`MagazineEject`	empty
`Unholster Humanoid Socket`	Where the gun hangs on the body when it is put away	`SecondarySocketHumanoid`	`PrimarySocketHumanoid`
`Unholster Backpack Socket`	Where it hangs on the backpack instead	empty	`PrimarySocketBackpack`

Use Unholster Backpack Socket chooses between the last two. It is false on the pistol, which rides on the hip, and true on the shotgun, which rides on the backpack.

The safe move is to reuse the socket names of the shipped gun you copied. Your rifle can use ShotgunHandRSocket and hang in PrimarySocketHumanoid without you creating anything. Only add a socket when your mesh genuinely does not sit right in the existing ones.

Two more fields concern the left hand:

Use Custom Left IK drives the off hand onto the gun. Both shipped guns have it on.
Join Target Location is the offset it aims for, and it is only read when Use Custom Left IK is on. It is 300, 500, -5000 on the pistol and 100, -100, 0 on the shotgun, so treat it as a value you nudge until the hand lands, not one you calculate.

Step 5, make the weapon class¶

In Content/TheLastTemplate/Blueprints/Weapons/Childs/, duplicate BP_Weapon_Pistol_01 and name it after your gun, for example BP_Weapon_Rifle_01.
Open it. Select the Weapon Skeletal Mesh component and set its Skeletal Mesh to your gun.
In Class Defaults, set Weapon Data to the Data Asset you made in step 1.
Move the scene components in the viewport until they sit on your mesh.
Compile and save.

The components you move:

Component	Put it
`Muzzle Fire Arrow`	At the muzzle, pointing forward along the barrel
`Eject Ammunition Arrow` and `Eject Ammunition Spawn`	At the ejection port, facing the way the shell should fly
`Eject Magazine Arrow`	At the magazine well, facing down
`Hand IK Weapon Left`	Where the left hand should grip

That is the whole class. Weapon Data is the only value on it you set, and there is nothing else in it for you to edit.

Step 6, ammo¶

Reserve ammo is tracked per weapon class, and the thing that identifies an ammo type is the ammo pickup class. So a gun that uses new ammo needs a new pickup class, and three references have to agree.

In Content/TheLastTemplate/Blueprints/Environments/Interactable/Pickup/Ammo/Childs/, duplicate BP_Interactable_Pickup_Ammo_Pistol and name it, for example BP_Interactable_Pickup_Ammo_Rifle.
Set its Weapon Needed Classes to the list of weapon classes this box feeds. The pistol box lists both BP_Weapon_Pistol_01 and BP_Weapon_Pistol_02.
Set Amount to how many rounds one box gives. The pistol box gives 8, the shotgun box gives 4.
Set Static Mesh to your ammo box mesh and Interact Text to the prompt line, for example Rifle ammo box.
Back in your Data Asset, set Munition Class to this new pickup class.
Open Content/TheLastTemplate/Blueprints/ActorComponents/BP_PlayerWeaponManager and add a row to Max Ammo: your ammo pickup class as the key, the reserve cap as the value.

If your gun uses ammo a shipped gun already uses, skip all of this. Point Munition Class at the existing pickup class and add your weapon class to that pickup's Weapon Needed Classes.

Warning

Max Ammo ships with exactly two rows, BP_Interactable_Pickup_Ammo_Pistol at 16 and BP_Interactable_Pickup_Ammo_Shotgun at 8. A new ammo type with no row there caps at zero: the gun fires the magazine it spawns with, and every ammo box the player walks over does nothing. There is no error message.

Step 7, put it in the world¶

In Content/TheLastTemplate/Blueprints/Environments/Interactable/Pickup/Weapons/Childs/, duplicate BP_Interactable_Pickup_Pistol_01.
Set Weapon Class to your weapon class.
Set Static Mesh to the mesh the player sees lying on the floor. This is a static mesh, not the skeletal mesh the gun uses in hand. The pistol pickups use SM_Pistol, the shotgun pickups use SM_Shotgun_Collision and SM_Shotgun_02_Collision.
Set Interact Text to what the prompt says, for example Rifle.
Drag it into your level.

Drag the ammo pickup from step 6 in as well, so the player can refill.

Step 8, the holstered gun¶

When the player puts a weapon away, the real weapon actor is not what you see on their back. A separate cosmetic actor, BP_CosmeticWeapon, is attached to the socket you named in step 4. It exists so the gun on the body costs nothing while it is not being used.

The mesh it wears comes from Unequip Attached Mesh on your Data Asset. DA_Pistol_01 sets it to SK_Pistol, which is the same skeletal mesh BP_Weapon_Pistol_01 wears in the hand, and DA_Shotgun_01 sets it to SK_Shotgun. Set it to your gun's mesh and the holstered look is done.

Which socket it uses is the Unholster Humanoid Socket / Unholster Backpack Socket pair from step 4. There is more on this, and on what the player can carry at once, in Ammo, reserves and holstered guns.

The fields that break a gun if you leave them empty¶

Everything else can be empty and the gun still works. These cannot.

Field	Where	If it is empty
`Weapon Data`	your weapon class	The gun has no numbers at all. Nothing works.
`Skeletal Mesh`	the `Weapon Skeletal Mesh` component	An invisible gun.
`Clip Size`	Data Asset	Left at 0, the magazine holds nothing.
`Weapon Grip Socket R`	Data Asset	The gun attaches to the character mesh origin instead of the hand, so it sits at their feet.
`Weapon Overlay`	Data Asset	Left on `Base`, the character holds the gun with the empty-handed pose.
`Munition Class`	Data Asset	The gun has no ammo type, so it can never be refilled.
`Max Ammo` row	`BP_PlayerWeaponManager`	Ammo pickups are collected and thrown away.
`Weapon Type Socket`	Data Asset	Left on `None`, the gun has no carry slot.

While you are testing, Infinite Ammo on BP_PlayerWeaponManager lets you fire without minding the reserve. Turn it back off before you ship.

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