Flattening a grid from CNC probing

I have a file from a friend which is a grid scanned from a kitchen door with a simple engraved flower. Unfortunately after 30 hours of scanning the program died and the outer edge of a circular object is not quite complete. I think I can delete it and replace it however a large part of this scan is a flat surface around the details. Is there a way to take all the Z values of points in a range say ± .010" and make them zero, essentially making it perfectly flat?FLOWER DESIGN PROBE, 2.stl (10.9 MB)

I used Rhino every day for about 6 years, but holy mackerel it has been almost 16 years since I stopped using it every day. Now it is mostly my goto repair tool for SolidWorks files from vendors.

If you can select the points in this “flat” area, then you can use the SetPt command.
Uncheck the X and Y so they do not change, and change the World Z to 0.

Any luck?

I haven’t had a chance to try it. No one told the alligators that I need to get this done.

I can’t see an effective way to get only the points to flatten. Is there a way to do something like this with a script or macro? Like if Z<.01 and Z>than -0.01 then Z = 0. I would think that would do exactly what I need but I am not much of a programmer any more.