Flatness Question

[[Ra...]]

Why is my flatness of plane a lot less than taking points and doing distance for comparison.

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[[Cl...]]

Are you sure you want the Y distance? Is the plane in the Z space axis?
The Z actual looks like it makes more sense?

[[Ra...]]

Its Y Axis.

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[[Ma...]]

Because flatness is not affected by alignment. Your plane is not in +Y vector - it has some A1 and A2 angles.
Those points are clicked on model or by hand, because nominals don't match either?

[[Da...]]

You cannot directly compare those two values. The flatness uses an inherent alignment based on the direction of the Minmax or Chebycheff element. If you use the plane as primary alignment, the values should basically match, but only if you force the Minmax element for the alignment.

[[Ra...]]

So im taking a Plane Off the Top for Z , Plane Off right and a Plane from the front of the part shown in the image.

If i go to features, plane, evaluation constraints and turn on normal vector direction. The flatness is similar to the Y distance taken with points.

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[[Ky...]]

That would line up with what Martin is saying. Flatness will adjust to the best normal vector of the plane to give the best result. When you constrain that normal vector, you are stopping it from doing it. It constrains the feature to be parallel to the Y axis of the alignment (whatever that happens to be).