Table Function Interpolation

Table function can be interpolated. 

 To set up the function interpolation type

  1. Select the table function in the graphical editor or in the Projects view. 
  2. In the Properties view, choose the corresponding interpolation type from the Interpolation drop-down list.

The possible interpolation types are listed below.

 If you want to get a smooth curve, the spline interpolation is the best. However, it takes more time to calculate a spline interpolation than a linear one. So, if a discontinuous function is acceptable, use the linear interpolation.

Interpolation type

Description and Example


No interpolation applied.


Step interpolation. The function value between two points is the same as in the point with less argument value.


Linear interpolation. The points are connected with straight-line segments.


4th order spline interpolation. The points are connected with 4th order polynomial segments. For each point 0th, 1st, and 2nd derivatives of right and left segments are equal. The 2nd derivative in the ending points equals zero.


The resulting function is a polynomial of Order you specify in the edit box on the right, formed in order the sum of the root-mean-square error in the points is minimal.

Related topics

 Table functions

 Function behavior in infeasible area

 Accessing table function values