Surface plot or polyline plot

Ok so I am using it now, I did extract selections and it works perfectly.

Here is attached state file with my adjustments and the following screenshot is taken from it.

Offset_on_blade_0.05_extracted.pvsm (2.5 MB)

I have another question also related:

** What I would like to do is not really an offset, but rather take a polyline with exactly between two blades and plot against it. But I came across this thread and thought it might be an option, is there an easier way to do it? Since having an offset gives me two lines in the middle of the passages. Here is the thread i opened about it:

Thanks!