Hi @Chavdar,

In Fields Calculator, we use Lagrange basis functions for interpolation, with barycentric coordinates for tetrahedral and triangle elements. To calculate the value of any expression at a point, we first find the barycentric coordinates for that point and then perform the evaluation. From Maxwell solvers, most field quantities are represented in 2^{nd} order polynomial over the elements. In Fields Calculator, if further operations are involved, the order of the expression might be higher.

GLUO