load( url, onLoad, onProgress, onError ) {

		const fileLoader = new FileLoader( this.manager );
		fileLoader.setPath( this.path );
		fileLoader.setRequestHeader( this.requestHeader );
		fileLoader.setWithCredentials( this.withCredentials );
		fileLoader.load( url, text => {

			// Initializes the materials library with default materials
			this.addDefaultMaterials();

			this.partsCache
				.parseModel( text )
				.then( group => {

					this.applyMaterialsToMesh( group, MAIN_COLOUR_CODE, this.materialLibrary, true );
					this.computeBuildingSteps( group );
					group.userData.fileName = url;
					onLoad( group );

				} )
				.catch( onError );

		}, onProgress, onError );

	}
Starts loading from the given URL and passes the loaded LDraw asset
to the `onLoad()` callback.

@param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
@param {function(Group)} onLoad - Executed when the loading process has been finished.
@param {onProgressCallback} onProgress - Executed while the loading is in progress.
@param {onErrorCallback} onError - Executed when errors occur.