expandByPoint( point ) {

		if ( this.isEmpty() ) {

			this.center.copy( point );

			this.radius = 0;

			return this;

		}

		_v1$6.subVectors( point, this.center );

		const lengthSq = _v1$6.lengthSq();

		if ( lengthSq > ( this.radius * this.radius ) ) {

			// calculate the minimal sphere

			const length = Math.sqrt( lengthSq );

			const delta = ( length - this.radius ) * 0.5;

			this.center.addScaledVector( _v1$6, delta / length );

			this.radius += delta;

		}

		return this;

	}
Expands the boundaries of this sphere to include the given point.

@param {Vector3} point - The point to include.
@return {Sphere} A reference to this sphere.