How can I mask points of a freeform surface?

[[No...]]

Hi, I measure a very small freeform surface and need to exclude a certain circular area from evaluation. I use scanned point sets in my strategy and it would be very difficult to exclude the area during scanning, because the surface is so small and the tip radius is rather large in comparison. I fear the stylus might touch that area anyway and produce faulty points. It'd be better to mask the area afterwards, but I have no idea how to do that.

[[Ma...]]

I think you can not.

But if you make a 3d curve from FF path, then you can recall measured points into a curve and now you can mask and evaluate.
But to be sure we would need to know how FF looks like and it's points/path.
With points far away and big curvature you can have wrong evaluation.

Also i just wonder - you could possibly recall filtered points from curve back into a FF