Ignore zero values in range for user defined function

Hello,

I imported in my workbook a spline function that someone else has made, MySpline. MySpline takes two column ranges of equal lengths, one as

x-values you could say andone as y values, and one new x-value to be interpolated.

Now I am trying to make a template, so the input ranges will be fixed, fx A3:A13 and B3:B13. Users will insert their values in these two columns.

However, the inputs may vary. Fx let's say that one user only has data that fill A3:A9 and B3:B9. In that case, the remaining cells will be

empty and MySpline cannot handle that.

So I've tried different things. I've tried changing the VBA code of MySpline with something like

NewRange = InputRange(InputRange <> 0)

I've tried the same following the method poste dby Kenneth here: VBA code to select cells with value greater than zero from a range.

I've tried

MySpline($A$3:INDEX(A:A,COUNT(A:A)),$B$3:INDEX(B:B,COUNT(B:B)),C3)

However, there are some headers at A1 and A2, so

INDEX(A:A,COUNT(A:A)) 

doesn't give the correct last value in the column. It would give the value in A11.

I've tried

MySpline($A$3:LOOKUP(2,1/($A$3:$A$13<>""),$A$3:$A$13)),$B$3:LOOKUP(2,1/($B$3:$B$13<>""),$B$3:$B$13)),B3

But I figured out that INDEX and LOOKUP don't work together.

I've tried making the cells be empty (see Return empty cells and here - the part with the "suicide cells") for some reason the "suicide cell function" doesn't work for me.

Now I've run out of ideas... Is there anyone who could help? Either with a better idea or improving my previous ideas.

I can do this with a button and VBA, however I would prefer a solution without no user interaction other than the input, such that the user inputs some data, MySpline does the math.

NB: I am not exactly sure if this is the right place to post this and if I'm using the "code" function correctly as I am new here...

Hi, I can unfortunately not do that I tried to write a detailed description hoping it would describe enough