There are basically two methods to define the race track layout:
Geometric definition around the centre line, where the track is divided into several sections, for which the user has to specify the length, the curve radius, the climbing and tilting (or banking) angle, the grip factor, the width, ...
Definition derived from telemetry data.
For the first case, SimOLap can calculate different drive lines:
Shortest. This drive line is determined by SimOLap by selecting the shortest, in terms of running meters, possible line, that a car can follow to accomplish a lap on the circuit. This drive line does not really correspond to something a race driver should ever follow. It's just a feature to satisfy the user's curiosity.
Fast. When evaluating the fastest line, SimOLap tries to draw for each curve the absolutely "biggest" driveable curve radius. This will allow the highest curve speeds around the circuit.
Power. When evaluating the power line, SimOLap tries again to draw for each curve the "biggest" driveable curve radius, but this time, the curve outlet of the drive line coincides with the curve outlet of the centre line, so that the race car returns back to the straight forward motion, allowing the driver to fully accelerate his car as soon as possible. If the driver fully accelerates his car before having accomplished the curve motion, the driving wheels may slip and the car will break away on its driving axle.
Battle. When evaluating the battle line, SimOLap tries again to draw for each curve the "biggest" driveable curve radius, but this time, the curve inlet of the drive line coincides with the curve inlet of the centre line, so that the race car engages the curve, allowing the driver to brake as late as possible.