Damage stages

Damage stages let an object visibly deteriorate before it breaks.

Intact
↓
Damaged 1
↓
Damaged 2
↓
Destroyed

They are optional and disabled by default: an empty DamageStages array means an object goes straight from intact to destroyed.

Defining a stage

Each FSDFDamageStage in the profile’s DamageStages array:

Property	Default	Meaning
HealthRatioThreshold	0.5	The stage activates when the remaining health ratio is at or below this value (0–1)
StaticMesh	none	Optional replacement mesh; empty keeps the mesh currently displayed
MaterialOverrides	empty	Optional per-slot replacements; empty or null entries preserve their existing slots
StageName	none	Optional semantic identifier for your own presentation logic

Thresholds are evaluated by value

Stages are matched by their threshold value, not by their position in the array. Listing a 0.3 stage before a 0.66 stage does not change behaviour. Array order is not gameplay-significant.

For a crate with MaxHealth = 100:

Stage A: HealthRatioThreshold = 0.66  -> activates at 66 health
Stage B: HealthRatioThreshold = 0.33  -> activates at 33 health

Stage skipping

A single heavy hit can cross several thresholds at once. The component evaluates the current health ratio and applies the appropriate stage directly — it does not step through the intermediate ones. A crate at full health taking 80 damage jumps straight to the 0.33 stage.

No regression

Within one damage lifecycle, the stage index never moves backwards. A healing or repair system that restores health does not visually un-break the object; the appearance stays at the worst stage reached until the object is reset.

Mesh replacement

When a stage carries a StaticMesh, the intact component’s mesh is swapped for it. The reference is soft, so the damaged meshes are loaded on demand rather than pinned by the profile.

Leaving StaticMesh empty is normal: many props only need material changes.

Material overrides

MaterialOverrides is per-slot and index-aligned with the intact component’s material slots. A null or empty entry preserves the material already assigned to that slot, so you can change slot 1 without restating slot 0.

Typical use: swap the base material for a variant with cracks, soot or exposed interior.

Stage change events

Every transition broadcasts OnDamageStageChanged with an FSDFDamageStageChange:

Field	Meaning
SourceActor	The object that changed stage
PreviousStageIndex	Index before the change (-1 when there was none)
NewStageIndex	Index after the change
StageName	The stage’s semantic name, when set
RemainingHealthRatio	Health ratio at the moment of the change
bMeshApplied	Whether a replacement mesh was applied
MaterialOverridesApplied	How many slots were overridden

GetCurrentDamageStageIndex and GetLastDamageStageChange expose the same information on demand.

Use the event to layer your own presentation — a dust puff, a creak, a UI hint — without adding any per-object Blueprint logic to the framework.

Choosing thresholds

Object	Suggested stages
Crate, barrel	Two stages at 0.66 and 0.33
Statue, pillar	One stage at 0.5, since heavy props rarely survive long enough for more
Fragile pot	None — a pot that breaks on the first valid hit never reaches a stage

Stages cost an asset each. Two well-read stages beat four subtle ones.

Damage stages versus destruction

Damage stages are pure presentation on the intact representation. They do not change health, resistance or the power gate, and they never destroy the object. Destruction is decided entirely by the rules in Destruction profiles.