add() {

		const objects = this._objects,
			indicesByUUID = this._indicesByUUID,
			paths = this._paths,
			parsedPaths = this._parsedPaths,
			bindings = this._bindings,
			nBindings = bindings.length;

		let knownObject = undefined,
			nObjects = objects.length,
			nCachedObjects = this.nCachedObjects_;

		for ( let i = 0, n = arguments.length; i !== n; ++ i ) {

			const object = arguments[ i ],
				uuid = object.uuid;
			let index = indicesByUUID[ uuid ];

			if ( index === undefined ) {

				// unknown object -> add it to the ACTIVE region

				index = nObjects ++;
				indicesByUUID[ uuid ] = index;
				objects.push( object );

				// accounting is done, now do the same for all bindings

				for ( let j = 0, m = nBindings; j !== m; ++ j ) {

					bindings[ j ].push( new PropertyBinding( object, paths[ j ], parsedPaths[ j ] ) );

				}

			} else if ( index < nCachedObjects ) {

				knownObject = objects[ index ];

				// move existing object to the ACTIVE region

				const firstActiveIndex = -- nCachedObjects,
					lastCachedObject = objects[ firstActiveIndex ];

				indicesByUUID[ lastCachedObject.uuid ] = index;
				objects[ index ] = lastCachedObject;

				indicesByUUID[ uuid ] = firstActiveIndex;
				objects[ firstActiveIndex ] = object;

				// accounting is done, now do the same for all bindings

				for ( let j = 0, m = nBindings; j !== m; ++ j ) {

					const bindingsForPath = bindings[ j ],
						lastCached = bindingsForPath[ firstActiveIndex ];

					let binding = bindingsForPath[ index ];

					bindingsForPath[ index ] = lastCached;

					if ( binding === undefined ) {

						// since we do not bother to create new bindings
						// for objects that are cached, the binding may
						// or may not exist

						binding = new PropertyBinding( object, paths[ j ], parsedPaths[ j ] );

					}

					bindingsForPath[ firstActiveIndex ] = binding;

				}

			} else if ( objects[ index ] !== knownObject ) {

				console.error( 'THREE.AnimationObjectGroup: Different objects with the same UUID ' +
					'detected. Clean the caches or recreate your infrastructure when reloading scenes.' );

			} // else the object is already where we want it to be

		} // for arguments

		this.nCachedObjects_ = nCachedObjects;

	}
Adds an arbitrary number of objects to this animation group.

@param {...Object3D} arguments - The 3D objects to add.