How spline interpolation works

With spline interpolation, a profile is determined across all curve points so that the position, speed and acceleration profiles are continuous. As with cubic interpolation, this makes it possible to control the behavior at the margins.

An essential characteristic is that the system of n curve points and consequently (n-1) sections, in which interpolation is to be performed using a 3rd order polynomial, is under-determined. The user must use the eSplineMode parameter to specify two conditions that are also taken into account in the calculation. This can be, for example, that the acceleration at both margins should be 0 (eSplineMode = "Natural") or that the acceleration and speed at the margins should be the same (eSplineMode = "Periodic"). However, there are also numerous other options.