Fall damage, death and the ragdoll¶

A character that lands hard loses health. A character whose health reaches zero drops to a ragdoll and stays on the ground. Both are already wired on the characters that ship.

Where fall damage lives¶

One component: Content/TheLastTemplate/Blueprints/ActorComponents/BP_FallDamageComponent.

Three characters carry it: BP_PlayerCharacter, BP_NPCCharacter and BP_ZombieCharacter.

Add it to any Character and it works. It binds to the character's own landing event, so there is nothing to connect. It reads the fall height from the speed the character hits the ground at and from the world gravity, not from where the fall started, so it is correct however the character got into the air.

The damage itself goes out as a normal Apply Damage on the owner. That means fall damage passes through BP_VitalsSystem like every other hit, and Invulnerable and Damage Taken Multiplier apply to it. See How a character takes damage.

The fields, and what ships¶

Select BP_FallDamageComponent in the Components tree of a character to see these in the Details panel. The values below are the ones the component itself ships with. Heights are in centimetres, like everything else in Unreal.

Field	Shipped	What it does
`Fall Damage Enabled`	`true`	Uncheck to switch fall damage off for that character.
`Safe Fall Height`	`300`	Fall this far or less and nothing happens.
`Lethal Fall Height`	`900`	At this height and beyond you take `Max Fall Damage`.
`Min Fall Damage`	`8`	The damage a fall costs the moment it passes `Safe Fall Height`.
`Max Fall Damage`	`150`	The damage at `Lethal Fall Height` and above.
`Damage Exponent`	`2`	The shape of the curve between the two heights.

Two more fields are on the component but are filled in at play time, not authored: Last Fall Damage and Last Fall Height. They hold the last landing, and they are useful when you react to a fall.

What the shipped numbers give you¶

Below three metres, nothing. Above nine metres, 150 damage. A character starts with 100 health, so nine metres is always fatal, which is what the name of the field promises.

Between the two, Damage Exponent decides. At 1 the damage climbs in a straight line. At 2, the shipped value, it stays low for the first half of the range and then rises fast, so a medium drop is survivable and a bad one is not:

Fall	Damage
3 m or less	none
4.5 m	about 17
6 m	about 44
7.5 m	about 88
9 m or more	150
## Turn fall damage off for one character

Uncheck Fall Damage Enabled on that character's component. Nothing else has to change, and the component can stay where it is.

If you are building a character that must never take fall damage at all, simply do not add the component. BP_Dummy is set up that way.

React to a fall from your own Blueprint¶

The component has an event dispatcher, On Fall Damage, which fires with the damage and the fall height every time a landing hurts. Nothing in the template listens to it. It is there for you.

In your character's Event Graph, drag off BP_FallDamageComponent.
Pick Assign On Fall Damage, or Bind Event to On Fall Damage if you already have an event to use.
Do what you want with the two values: a grunt, a camera shake, a limp, a broken leg state.

What death does by default¶

Health reaching zero is BP_VitalsSystem's business. It raises its On Death dispatcher, and each character decides for itself what that means.

An AI, BP_NPCCharacter or BP_ZombieCharacter, stops its montage and hands the skeletal mesh over to physics. The body falls, keeps its momentum, and stays where it lands. Nothing destroys it and nothing cleans it up. If you want corpses to disappear, add a Set Life Span after the ragdoll starts.

The player disables input, plays the same ragdoll, and puts BP_DeathScreenWidget on screen. The widget class it uses is a field on the player, BP Death Character Widget, so you can swap in your own screen without opening a graph. The screen has two fields of its own in Class Defaults: Death Tips for the line of text drawn at random, and Continue Key Icon for the prompt.

`PlayDeathRagdoll`, one per character class¶

PlayDeathRagdoll is a function on the interface Content/TheLastTemplate/Blueprints/Interfaces/BPI_AICombatant. BP_PlayerCharacter, BP_NPCCharacter and BP_ZombieCharacter each implement their own version and call it from their own death handler.

That is deliberate. A player death has a screen to bring up, an AI death does not, and a character of yours will have its own needs. The interface only fixes the name, so anything that implements it can be asked to die the same way.

To give your own character a ragdoll death:

Open your Character Blueprint and add the BPI_AICombatant interface in Class Settings.
Implement PlayDeathRagdoll.
In it, call Prepare for ragdoll on BP_HitReactionManager, then stop the montage, then start simulating physics on the mesh.
Bind the On Death dispatcher of BP_VitalsSystem in Begin Play and call PlayDeathRagdoll from it.

The physics asset the ragdoll uses¶

One asset for every character: Content/TheLastTemplate/Meshes/Characters/PA_HumanoidCharacter. It is set on SK_PlayerCharacter, SK_NPC_01, SK_NPC_02 and SK_Zombie_01.

So the way a body falls, folds and settles is tuned in one place, and the change lands on the player, the NPCs and the zombie at the same time. Open it, change the bodies, the constraint limits or the masses, and save.

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