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Weight and durability

Both are additive modules built on Core's extension points, and both are worth reading as examples of how a feature is added without touching Core.

Weight​

FEDWeightFragment gives an item a unit weight. An item without one weighs nothing.

UEDWeightComponent sums the weight an actor is carrying and fires when it changes:

Weight->OnWeightChanged.AddDynamic(this, &AMyCharacter::HandleWeightChanged);
const float Total = Weight->GetTotalWeight();

By default it counts every container the actor has. Set bIncludeAllContainers false to count only its main one — which is what you want if a stash should not slow the player down.

FEDWeightLimitRule is a container rule that refuses what would push it over a cap:

FieldMeaning
Max WeightThe cap.
Weight AttributeOptional GAS attribute, so a Strength perk raises it without touching the asset.

Because it is a rule, it is consulted at the same acceptance gate as everything else. A vendor's Buy button greys out with "That is too heavy" before the player clicks, and EvaluateAddItem and the real add can never disagree.

const float Item = UEDInventoryWeightStatics::GetItemWeight(Entry);
const float Bag  = UEDInventoryWeightStatics::GetContainerWeight(Container);

Durability​

FEDDurabilityFragment gives an item a maximum durability and what happens when it runs out.

Current durability is per-stack state, not a fragment field — it lives in the entry's FEDItemStateContainer, replicates with the entry, and saves with it.

UEDDurabilityStatics::GetDurability(Entry);
UEDDurabilityStatics::GetMaxDurability(Definition);
UEDDurabilityStatics::ApplyWear(Container, Handle, Amount);
UEDDurabilityStatics::Repair(Container, Handle, Amount);

Two consequences fall out of durability being per-stack state, and both are deliberate:

  • Two swords at different durability never stack. Merging them would have to invent a number.
  • A worn item keeps its wear through a move, because a transfer preserves handle and state.

What happens at zero — destroyed, rendered unusable, unequipped — is configured on the fragment, and the wear itself is your game's business. The framework does not know that swinging a sword should wear it out.

The pattern both follow​

  1. A fragment describing the item's participation. Absent means not participating.
  2. Statics that read it, so Blueprint and C++ get the same surface.
  3. Optionally a rule or an observer component, registered through Core's registries.

Nothing in Core knows either module exists. That is what "additive" means here, and it is the shape to copy for a feature of your own — see Extending.

Where next​

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