### Magnetic field lines via Runge-Kutta

BiotSavart (version 3.2 and higher) can trace magnetic field lines for general three-dimensional configurations of conductors using a Runge-Kutta approach. The field line is traced by integrating the fundamental equation

where *s* is the path length along the field line.

If the conductor geometry is not simple, magnetic field lines can be complicated.

Magnetic field line calculated using the Runge-Kutta algorithm. The field source is a square loop bent out of its plane.