Weapon overlays and animation layers¶

Two separate things decide how a character holds a weapon and how it moves while holding it.

An overlay is one pose blended onto the upper body. It is what makes the character look like it is carrying a shotgun instead of nothing. Which pose is used comes from an enum, E_OverlayLayers, and a weapon picks its own value in its Data Asset.

An animation layer is the locomotion set itself: the idle, the walk and run blend spaces, the stops, the turns in place. Layers live in their own animation blueprint that gets linked into the main one, so a weapon family can have its own walk cycles without you opening the main graph.

The assets involved:

Asset	Path
`E_OverlayLayers`	`Content/TheLastTemplate/Blueprints/Enumerations/Locomotion/`
`ABP_HumanoidCharacter`	`Content/TheLastTemplate/Blueprints/PlayerCharacter/Animations/`
`ALI_LocomotionLayers`	same folder
`ABP_LocomotionLayers`	same folder
`ABP_LocomotionLayer_Unarmed`	same folder, under `Childs/`
Overlay poses	`Content/TheLastTemplate/Animations/AnimSequences/Characters/Overlay/`
Aim offsets	`Content/TheLastTemplate/Animations/AimOffsets/`

BP_PlayerCharacter, BP_NPCCharacter and BP_ZombieCharacter all run ABP_HumanoidCharacter, and all three link ABP_LocomotionLayer_Unarmed. What you change here you change for the player, the NPCs and the zombies at once.

An overlay does not move the feet, does not change speed, and does not decide what the weapon does when you pull the trigger. It is upper body posture only. Movement speed lives in Change movement speeds and gaits.

The six overlays that ship¶

Value	What it is for	Poses that ship for it
`Base`	Empty hands. It is also the value all four NPC Data Assets use.	`AS_Humanoid_Overlay_UnarmedAim`
`Shotgun`	The two shotguns, `DA_Shotgun_01` and `DA_Shotgun_02`	`_Shotgun_Hip`, `_Shotgun_ADS`, `_Shotgun_Run`, `_Shotgun_Crouch`
`Pistol`	The two pistols, `DA_Pistol_01` and `DA_Pistol_02`	`_Pistol_Hip`, `_Pistol_ADS`, `_Pistol_Run`
`Throw`	Holding a throwable	`AS_Humanoid_Overlay_Throw`
`Combat`	Unarmed melee	`AS_Humanoid_Overlay_Combat`
`Zombie`	The zombie. `DA_Zombie_Roaming` sets it.	`AS_Humanoid_Overlay_Zombie`

The pose files all start with AS_Humanoid_Overlay_. Pistol and Shotgun each have their own subfolder because they carry several poses. The shotgun has a crouch pose and the pistol does not.

Point a weapon at an overlay¶

This is the whole job for a weapon that fits one of the six values above. No graph.

Open the weapon's Data Asset, for example Content/TheLastTemplate/Blueprints/DataAssets/Weapons/Childs/DA_Pistol_01.
Set Weapon Overlay to the value you want.
Save, then play and equip the weapon.

For an AI, the same idea lives on the AI Data Asset: Idle Overlay in Content/TheLastTemplate/Blueprints/DataAssets/AI/Childs/. DA_NPC_Path, DA_NPC_Stand, DA_NPC_Roaming and DA_NPC_Melee_Roaming all ship on Base, and DA_Zombie_Roaming ships on Zombie.

Change what a weapon family looks like¶

If you want a shotgun held differently, you do not need a new overlay value. Replace the poses.

Open AS_Humanoid_Overlay_Shotgun_Hip. That is the pose the shotgun is carried in.
Either re-import over it with your own single frame animation, or make your own sequence and point the matching node in ABP_HumanoidCharacter at it.
Do the same for _ADS, _Run and _Crouch so the four states agree with each other.

The four poses are separate on purpose: a weapon that reads well at the hip usually reads badly while running.

Left hand IK¶

The left hand is placed by a two bone IK driven from four fields on the weapon Data Asset. There is no graph work.

Field	What it does
`Use Custom Left IK`	Turns the left hand IK on for this weapon
`Use Custom Left IKSprinting`	Whether that IK stays on while sprinting
`Join Target Location`	The elbow target. It is only read when `Use Custom Left IK` is on.
`Weapon Grip Socket R`	The socket on the character skeleton the weapon is attached to

Shipped values:

Data Asset	`Join Target Location`	`Weapon Grip Socket R`
`DA_Pistol_01`, `DA_Pistol_02`	`300, 500, -5000`	`PistolHandRSocket`
`DA_Shotgun_01`, `DA_Shotgun_02`	`100, -100, 0`	`ShotgunHandRSocket`

All four ship with Use Custom Left IK on and Use Custom Left IKSprinting off.

Both weapon skeletons that ship, S_Pistol and S_Shotgun, carry a socket called LeftHandIK_Aiming. Give your own weapon skeleton a socket with that exact name and put it where the left hand should sit. The two shipped Join Target Location values are far apart, so copy the one for the weapon closest to yours and move it from there.

The character skeleton also carries InsertMunitionPistolSocket and InsertMunitionShotgunSocket, named on the weapon Data Asset by Left Hand Magazine Socket. That one is the reload, not the carry pose.

The layer interface and the one class that ships¶

ALI_LocomotionLayers declares five layers. ABP_LocomotionLayers implements all five, and ABP_LocomotionLayer_Unarmed is the only child that ships.

Layer	Covers
`LocomotionLayer_Idle`	Standing and crouched idle, plus the turns in place
`LocomotionLayer_Movement`	Walking, running and crouched movement
`LocomotionLayer_Stop`	The foot planted stops at the end of a move
`LocomotionLayer_NarrowPassage`	The shuffle used in tight spaces
`LocomotionLayer_Falling`	In air

A child class fills in animations, not graphs. These are the variables it sets:

Variable	Shipped in `ABP_LocomotionLayer_Unarmed`
`Idle Animation`	`AS_Humanoid_Stand_Idle_Loop`
`Crouch Idle Animation`	`AS_Humanoid_Crouch_Idle_Loop`
`Blendspace Walking`	`BS_HumanoidWalking`
`Blendspace Running`	`BS_HumanoidRunning`
`Blendspace Crouching`	`BS_HumanoidCrouching`
`Walking Stop Directions`	Eight stop sequences, four directions times the planted foot
`Running Stop Directions`	The same eight walk stop sequences again
`Crouching Stop Directions`	Eight stop sequences, four directions times the planted foot
`Normal Turn In Place Animations`	The standing turn set
`Crouching Turn In Place Animations`	The crouched turn set

Make your own layer class¶

Do this when a weapon family needs its own walk cycles, not just a different upper body pose.

Right click ABP_LocomotionLayers, then Create Child Blueprint Class. Name it after the family, for example ABP_LocomotionLayer_Rifle.
Put it next to the one that ships, in .../Animations/Childs/.
In Class Defaults, fill the variables from the table above with your own blend spaces and sequences.
Compile and save.
In the character that should use it, change the class passed to the Link Anim Class Layers node.

Step 5 is the part that is not data. BP_PlayerCharacter, BP_NPCCharacter and BP_ZombieCharacter each call Link Anim Class Layers once with ABP_LocomotionLayer_Unarmed, and nothing swaps it afterwards. If you want the layer to change when a weapon is equipped, that is where you call it again.

Adding a seventh overlay¶

The six values are not open ended. A new one costs two edits:

Add an entry to E_OverlayLayers.
Handle that entry in ABP_HumanoidCharacter, next to the six that are already there, and give it a pose.

There is no Data Asset that adds an overlay for you. If your weapon can live on Pistol or Shotgun with different poses, take that route instead: it is a lot cheaper.

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