Here is a sample Excel file.
It has 3 Named Values that you can change in cells C18, C19, and C20.
The cell with the formula calling T2LOOKUP is in B2.
Thanks for your help with this,
We could not calculate ‘C:\Program Files (x86)\Trimill\TriLookup\TriLookup’!T2LOOKUP() method.
If you simply set the formula as =ABS(IF(UCUT=“NO”,0,T2LOOKUP((REACH-LOC)/CUTDIA,CUTDIA,V26:AG35,-8,-8)))
You can try Workbook.CalculateFormula(bool ignoreError, ICustomFunction customFunction) method and implement T2LOOKUP function in ICustomFunction