Attribute model

Define AttributeSets

Gameplay Attributes live in native UAttributeSet classes as FGameplayAttributeData properties. Group them by coherent ownership/lifetime, for example:

• vitals: Health, MaxHealth, Stamina, MaxStamina;
• combat: AttackPower, Armor, critical parameters;
• movement: MoveSpeed or movement multipliers;
• transient meta inputs: IncomingDamage or IncomingHealing.

An ASC can access registered AttributeSets. Avoid one giant set merely because it is easy to create; avoid splitting so finely that related invariants become hard to enforce.

Base and current values

• Base value: durable value before temporary modifiers.
• Current value: evaluated result including active modifiers.
• Instant Gameplay Effects change base values.
• Duration and Infinite effects modify current values while active and are undone when they expire or are removed.

Use an effect for changes. Do not directly write a temporary bonus into the attribute, or its source/removal/stacking semantics become opaque.

Initialization

1. Create an Instant initialization Gameplay Effect with default attribute modifiers.
2. Create a spec at the correct level or with SetByCaller values.
3. Apply it from authority after ASC actor info and AttributeSets are ready.
4. Guard against duplicate application on respawn/repossession.
5. If ASC persists on PlayerState, explicitly decide which attributes persist and which reset for the new avatar.

Invariants and clamping

AttributeSets do not provide automatic min/max clamping. Data Table MinValue and MaxValue columns do not enforce bounds.

Enforce invariants deliberately:

• clamp proposed current-value changes in PreAttributeChange where appropriate;
• clamp permanent executed results in PostGameplayEffectExecute or the authoritative calculation/application path;
• when MaxHealth changes, decide whether Health preserves absolute value, percentage, or only clamps down;
• keep resource invariants explicit: 0 <= Health <= MaxHealth.

Do not assume a clamp in one hook covers every aggregator recalculation or execution path.