function ModelAlphaOptions() {
  /**
   * Which render pass will render the model.
   *
   * @type {Pass}
   * @private
   */
  this.pass = undefined;
  /**
   * Determines the alpha threshold below which fragments are discarded
   *
   * @type {number}
   * @private
   */
  this.alphaCutoff = undefined;
}
Options for configuring the {@link AlphaPipelineStage}

@alias ModelAlphaOptions
@constructor

@private