Perpendicular distance

[[Ja...]]

I am trying to understand difference between "length of perpendicular" v/s cartesian distance.

I have a long shaft (probed two circles on each end and recalled into 3D line for axis 'A-B'). I am trying to get distance between shaft axis and several flats milled onto the shaft.
1) I used cartesian distance with feature 1 as the flat plane and feature 2 as axis 'A-B'. The results seem wrong when compared to that obtained by other method.
P.S.I got better results(same as method 2 below) if I constrain the plane feature to the axis 'A-B' of the shaft.
2) Got intersection pt between flat plane and a cylinder hole that is perpendicular to that flat plane. Got length of perpendicular from perpendicular construction between the intersection pt and axis 'A-B'

To verify results, I checked surface profile of that plane with base alignment and it matches with length of perpendicular results. Why is cartesian distance wrong in this case? Any input is appreciated.

[[To...]]

Since the cartesian distance is coming from the mid point of the plane, the plane may not be defined symmetrically to the centerline. Depending on the orientation, add one half of the Length 1 value to X or one half of the Length 2 to the Y and see if it is zero.

I am curious what the result is if you reverse the order, making it from the mid point of the 3d line, perpendicular to the plane.

[[Ja...]]

I tried out the plane nominal adjustment post measurement but it was a little off. I will try to remeasure it and see if results match.
I think this might work, will post as soon as I get the results.
Also, regarding flipping features in the cart dist characteristic is not an option. If I select, 3D line as first feature, it does not allow me to select a plane for second feature.

[[To...]]

Please sign in to view this quote.

Oh yes. I forgot that happens sometimes. Not sure why it’s not allowed.