setFromPoints( points, optionalCenter ) {

		const center = this.center;

		if ( optionalCenter !== undefined ) {

			center.copy( optionalCenter );

		} else {

			_box$3.setFromPoints( points ).getCenter( center );

		}

		let maxRadiusSq = 0;

		for ( let i = 0, il = points.length; i < il; i ++ ) {

			maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( points[ i ] ) );

		}

		this.radius = Math.sqrt( maxRadiusSq );

		return this;

	}
Computes the minimum bounding sphere for list of points.
If the optional center point is given, it is used as the sphere's
center. Otherwise, the center of the axis-aligned bounding box
encompassing the points is calculated.

@param {Array<Vector3>} points - A list of points in 3D space.
@param {Vector3} [optionalCenter] - The center of the sphere.
@return {Sphere} A reference to this sphere.