Imagine you, Sovitek and I meet for fika. We all order a cappuccino, a cinnamon bun, and a small chocolate cookie. If you group us by our order we’d be in the same group, but that does not make us the same person.
Your points are similar; they might show the same X value, Y value, and Z value, but they aren’t the same cappuccino, cinnamon bun, or cookie even though when you look at them zoomed out they appear the same… errr make that X Y and Z values (I’m now hungry).
Point.PruneDuplicates basically takes the X, Y, and Z values without rounding and looks at the distance from the first point to all other points mathematically, removing any that are less than the tolerance provided.
Often if you pull the true values of those XYZs (point.X, point.Y, and point.Z) you’ll see the full size that I’m talking about, off by 1/100000000000 of a unit…