expandByVector( vector ) {

		this.min.sub( vector );
		this.max.add( vector );

		return this;

	}
Expands this box equilaterally by the given vector. The width of this
box will be expanded by the x component of the vector in both
directions. The height of this box will be expanded by the y component of
the vector in both directions. The depth of this box will be
expanded by the z component of the vector in both directions.

@param {Vector3} vector - The vector that should expand the bounding box.
@return {Box3} A reference to this bounding box.