Racetracks are used in particle accelerators and neutral atom traps. BiotSavart implements planar racetracks. The dimensions of the racetrack are specified by the quantities
| length | straight section length |
| span | distance between straights |
| width | width of conductor (in plane) |
| height | height (out of plane) |
The turns at the ends of the racetrack are semicircular. This is approximated, both in drawing and field calculation, by finite angular steps. The number of steps in the semicircle is set by, e.g., nturn 10. The computation time is proportional to nturn+2, so it is best to use a small number unless an accurate depiction of the end fields is desired. The magnetic field is calculated by subdividing the racetrack into filamentary wires. The finesse of the subdivision is set by the resolution box. Choose it wisely. Suppression of field divergence inside the conductor is automatic.