updateBounds () {
    // Update member local matrices and the overall bounds
    const bbox = this.geometry.boundingBox.makeEmpty();
    this._members.forEach((_, text) => {
      if (text.matrixAutoUpdate) text.updateMatrix(); // ignore world matrix
      tempBox3.copy(text.geometry.boundingBox).applyMatrix4(text.matrix);
      bbox.union(tempBox3);
    });
    bbox.getBoundingSphere(this.geometry.boundingSphere);
  }
Update the batched geometry bounds to hold all members