dispose() {

		const resources = new Set();

		this.traverse( ( object ) => {

			if ( object.isMesh ) {

				resources.add( object.geometry );
				resources.add( object.material );

			}

		} );

		for ( const resource of resources ) {

			resource.dispose();

		}

	}
Frees internal resources. This method should be called
when the environment is no longer required.