at( t, target ) {

		return this.delta( target ).multiplyScalar( t ).add( this.start );

	}
Returns a vector at a certain position along the line segment.

@param {number} t - A value between `[0,1]` to represent a position along the line segment.
@param {Vector3} target - The target vector that is used to store the method's result.
@return {Vector3} The delta vector.