three.js/examples/jsm/utils/SceneUtils.d.ts

import { Geometry, Material, Object3D, Scene } from '../../../src/Three';

export namespace SceneUtils {
    export function createMultiMaterialObject(geometry: Geometry, materials: Material[]): Object3D;
    export function detach(child: Object3D, parent: Object3D, scene: Scene): void;
    export function attach(child: Object3D, scene: Scene, parent: Object3D): void;
}