Prefabs

A prefab is a saved entity hierarchy, a root entity and its children with all their components, stored as an asset. Place a prefab in a level and you get an instance, a live copy that stays linked to the source. Edit the prefab once and every instance picks up the change, while the edits you made to individual instances are kept.

Creating a prefab

In the world editor, build the hierarchy you want, then right-click it and choose Create Prefab from Entity… (or Create Prefab from Selected… from the viewport). Pick a name and location and the selection is saved as a .lasset prefab.

Double-click the prefab in the Content Browser to open the Prefab Editor, a scene editor scoped to that one hierarchy.

Placing instances

Drag a prefab from the Content Browser into the viewport or the outliner to spawn an instance. Each instance is a full copy of the prefab’s entities and components, linked back to the source.

Overrides and inheritance

An instance starts out identical to the prefab. The moment you change one of its properties in the Details panel, that single property becomes an override: it holds your value, and the engine stops syncing it from the prefab. Everything you have not touched stays inherited.

This is what makes prefabs safe to keep editing after you have placed them:

• Inherited properties follow the prefab. Edit and save the prefab and the change flows into every instance, except where an instance has overridden that property.
• Overrides are preserved. Your per-instance edits survive prefab updates, world reloads, and re-saves.
• Overrides are per property. Changing one field of a component overrides only that field, including fields nested inside a struct. The rest keep inheriting. Arrays and optionals are treated as a single value, so overriding one element makes the whole list yours.

An overridden property shows the modified marker and a reset arrow in the Details panel, the same as any value changed from its default.

Reset to Prefab

Click the reset arrow (or right-click the property and choose Reset to Default) on an overridden property to drop the override and restore the prefab’s value, not the original class default. For a prefab instance the chain of defaults is:

Class default, then Prefab value, then Instance override.

Reset always steps one level back up that chain, to the prefab.

Transforms are always per instance

An instance’s transform, its position, rotation, and scale, along with the transforms of its child entities, are never overwritten by prefab edits. Placement is yours: moving an instance, or nudging one of its children, will not be undone when you save the prefab. Reset to Default still snaps a transform back to the prefab’s authored pose if you ask for it.

Adding and removing components

You can diverge structurally as well:

• Add a component to an instance and it stays; a prefab update will not strip it.
• Remove an inherited component from an instance and it stays removed; a prefab update will not add it back.

The child entity structure of an instance follows the prefab. To add or remove entities, edit the prefab, not the instance.

Editing the source prefab

Open the prefab, change it, and save. Instances in any open level update right away (the inherited parts only). Instances in levels that are currently closed update the next time you open them. Overrides stay put either way.

Detaching

Right-click an instance and choose Detach from Prefab to break the link. The instance becomes plain entities: it keeps its current values but no longer inherits from, or is affected by, the prefab. Detaching is one way.

Deleting a prefab

Deleting a prefab asset removes its placed instances from every open level, the same as deleting any other asset clears references to it. Detached copies are no longer linked, so they survive. See Deleting assets.