Why PbrBundle bundle in childern can not be displayed?

[zzhgithub]

Hi when i create a entity and insert a PbrBundle. it can display;
But When i add add_children and spawn_bundle it can not display.Why? Can not i do this? the code maybe like this:

fn dynamic_render_system(
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut commands: Commands,
    query: Query<(Entity, &Transform), Added<Cube>>,
) {
    const CUBLE_SIZE: f32 = 1.0;
    let texture_handle: Handle<Image> = asset_server.load("a.jpg");
    // 声明一个 2D 的贴图
    let quad_handle = meshes.add(Mesh::from(shape::Quad::new(Vec2::new(
        CUBLE_SIZE, CUBLE_SIZE,
    ))));
    // 使用图片生成一种文理
    let material_handle = materials.add(StandardMaterial {
        base_color_texture: Some(texture_handle.clone()),
        alpha_mode: AlphaMode::Blend,
        unlit: true,
        ..default()
    });

    // 查询新增的 组件
    for (ele, transform) in query.iter() {
        // 这里 是测试代码 如果组件的 y 小于等于0就进行渲染
        // info!("checked");
        if transform.translation.y == 0.0 {
            commands.entity(ele)
             .add_children(|childern| {
                 childern.spawn_bundle(PbrBundle {
                     mesh: quad_handle.clone(),
                     material: material_handle.clone(),
                    transform: get_transform_by_face_type(
                         FaceType::Up,
                         Transform::from_xyz(0.0, 0.0, 0.0),
                         CUBLE_SIZE,
                     ),
                     ..Default::default()
                 });
        }
    }
}

if i miss some tips please tell me?

[rparrett]

You don't show ele being spawned, but I would guess that it is missing some components that are required for visibility propagation.

Root entities of hierarchies need Visibility and ComputedVisibility for visibility as well as Transform and GlobalTransform. You can spawn a SpatialBundle to get everything you need.

[zzhgithub]

prefect solve my issue~ Thanks hero!