Vitals: Shield, Barrier & Reservation

The defensive vocabulary ARPGs actually ship: a shield pool that absorbs before health and refills after a quiet period, a temporary barrier that can exceed maximum health and expires on a timer, and aura-style reservation that makes part of the health pool permanently unusable.

What lives where

Attributes

1. Grant the shield set

UCrimsonShieldSet is optional by design. Without it, UCrimsonHealthComponent reports zero for every absorb value, UCrimsonHealthSet skips the absorption chain entirely, and damage lands on health exactly as before. Most NPCs never need it.

Add it to the Granted Attributes array of the ability set your pawn uses, and fill in Default Values - order matters, because Shield is clamped to MaxShield and MaxShield is only derived once MaxShieldBase is written.

2. Absorption order

Incoming damage is spent Overhealth, then Shield, then Health, in UCrimsonHealthSet::PostGameplayEffectExecute. The expiring resource goes first: a barrier that times out unused is worse for the player than a shield that has to wait to recharge.

before hit          Health 328.12   Shield 150.0   Overhealth 140.0
250 damage
after hit           Health 328.12   Shield  40.0   Overhealth   0.0

  barrier absorbed 140, shield absorbed 110, health took 0

A hit that was absorbed stamps Damage.Result.Absorbed onto the effect context, and the hit that empties the shield also stamps Damage.Result.ShieldBroken, so combat text reports both without extra plumbing. The pop still shows the full incoming damage - the player wants to know what was swung at them, and the absorb tag is what says the pools ate it.

3. Barriers have no timer

MaxOverhealth is the sum of the currently active barrier effects. UCrimsonShieldSet::PostAttributeChange mirrors a rise onto Overhealth - barriers arrive full - and clamps it back down on a fall - barriers leave empty. A duration gameplay effect adding capacity is therefore the entire lifetime mechanism.

4. The recharge delay is a tag, not a timer

UCrimsonHealthComponent applies the effect in its Shield Recharge Block Effect property to the victim on every damaging hit. That effect grants Status.Shield.RechargeBlocked, and the recharge effect refuses to run while the target owns it. That pairing is the whole delay - no C++ anywhere has to know what time it is.

5. Reservation

An aura applies an infinite effect that adds to HealthReservedPercent via SetByCaller SetByCaller.Health.ReservePercent, as a fraction 0..1. Use Add (Base), never Override - several auras have to reserve at once, and HealthReserved is derived from the running total. Removing the effect frees the capacity immediately.

6. Put the bar on the HUD

UCrimsonCoreVitalsWidget does the binding, the retry-until-the-ability-system-replicates loop, repossession handling, the trail band and the eased fill. A Blueprint child needs only the visuals.

Register it at the HUD.Slot.Health extension point through a UCrimsonGameFeatureAction_AddWidget action, and make sure the HUD layout actually contains a CrimsonUIExtensionPoint carrying that tag - without one the widget registers successfully and appears nowhere, with no error.

7. Nameplates get the same bar

UCrimsonNameplateWidget looks for an optional child named Bar_Vitals of type CrimsonPoolBarWidget and pushes the layered snapshot straight into it - no graph wiring, and enemy plates pick up shield and barrier for free. Team color still applies: the widget calls SetHealthColor with the target's team tint.

OnVitalsVisual still fires alongside Bar_Vitals if you want a different treatment.

Binding is retried, not assumed

Attribute sets replicate as ability-system subobjects and routinely land several frames after the pawn. UCrimsonVitalsViewModel::TryBind is idempotent and returns false until the data is really there; the widget retries on a short timer and gives up after Rebind Timeout Seconds with a warning rather than spinning forever.

Testing

Console cheats on UCrimsonCheatManager. They are server-authoritative, so run them from the host window - a client has no cheat manager of its own (see below).

Multiplayer

• Absorption, reservation recalculation and the recharge-block application are server only - they run from PostGameplayEffectExecute, which is authority-side.
• Every attribute here is replicated; clients receive final values and never re-derive them. RecalculateHealthReserved returns early off authority for exactly that reason.
• UCrimsonVitalsViewModel and the bar are local and read-only. They are safe on a simulated proxy and never mutate gameplay.
• The trail band, the eased fill and the flash are cosmetic and local. They are driven by replicated value changes, so each client animates its own.

See also

• CrimsonUI -> How-To: Layered Pool Bars - the renderer, its style and its motion.
• Nameplates - floating plates and boss bars.
• Character Pipeline - where the health component comes from.
• Testing Dummy - a target to hit while checking absorption.