Usage

Imagine you have a model file with the following structure in Blender:

Collection
├── Armature
│   ├── Bone.Root
│   │   └── Bone.Neck
│   │       └── Bone.Head
│   └── Bone.Head.IK_CTRL

You can define a component like this:

#[derive(Component, EntityCollectorTarget)]
#[name_path("Armature")]
pub struct MyTurretArmature {
 #[name_path("Bone.Root")]
 pub base: Entity,
 #[name_path("Bone.Root", "Bone.Neck")]
 pub neck: Entity,
 #[name_path("Bone.Root", "Bone.Neck", "Bone.Head")]
 pub head: Entity,
 #[name_path("Bone.Head.IK_CTRL")]
 pub head_ik_ctrl: Entity,
}

Then, you need to add a Plugin, this plugin will handle the insertion of this component:

Each different EntityCollectorTarget needs its own plugin added!

In this example this is a GLTF model, so I want the root entity to be resolved as a scene. HierarchyRootPosition::Scene tells the plugin to find the root of the hierarchy based on #[name_path("Armature")] among the grandchildren of the entity where I want this MyTurretArmature to be inserted into.

app.add_plugins(DescendantCollectorPlugin::<MyTurretArmature>::new(HierarchyRootPosition::Scene));

And lastly, I need to identify the entities where I want MyTurretArmature to be inserted into! To do this, when you spawn this scene, add the target component to your entity.

fn spawn_turret(mut commands: Commands, turret_model_assets: Res<TurretModelAssets>) {
 commands.spawn((
  SceneBundle {
   scene: turret_model_assets.turret_model.clone(),
   ..default()
  },
  DescendantCollectorTarget::<MyTurretArmature>::default(),
 ));
}