Hi @Ineedhelpformy hesis,

The merit function will always be positive. The value of the merit function is computed based on how close the operand values are to their target. In other words, the calculation of the merit function is related to the value of your REAY or REAX operand, but it does not give those numbers directly. The merit function is defined by the following equation in OpticStudio:

where W is the weight, V is the value, and T is the target of each operand. Therefore, to get the value of REAX or REAY, you will need to view them in the Merit Function Editor directly and save the data from Values column.

With the ZOS-API, you can collect these values directly instead of retrieving the value of the Merit Function. Here is a snippet of MATLAB code that retrieves the REAX operand value:

MFE = TheSystem.MFE;

RayX = MFE.GetOperandValue(ZOSAPI.Editors.MFE.MeritOperandType.REAX, 

     surface, 

     wave,

     Hx,

     Hy,

     Px,

     Py,

     0, (not used)

     0, (not used)

     );

Best,
Ethan