With blade element theory, a surface (e.g. wing) may be made up of many sections (1 to 4 is typical), and each section is further divided into as many as 10 separate subsections. After that, the lift and drag of each section are calculated, and the resulting effect is applied to the whole aircraft. When this process is applied to each component, the simulated aircraft will fly similar to its real-life counterpart. This approach allows users to design aircraft quickly and easily, as the simulator engine immediately illustrates how an aircraft with a given design might perform in the real world. "X-Plane" can model fairly complex aircraft designs, including helicopters, rockets, rotorcraft, and tilt-rotor craft.