When I build a FCF (XactMeasure) to evaluate True Position, it shows in 3 segments on the report:
1) Size (self-explanatory on report)
2) Position (again, self-explanatory)
3) Summary (this is the confusing part)
On the surface, the “Summary” section looks straightforward, reporting deviation in the X, Y, and Z axes.
Looking closer at the values reported, I see that the axes have rotated – twice!
What was my “X” value is now my “Y”, “Y” is now “Z”, and “Z” is “X”. This is a 90-degree rotation about “Y” then 90 degrees about “X” (or 90 about “Z” then 90 about “Y”).
So, the impact is: If I take my X & Y values and calculate Positional error, I get a certain value, which agrees with the “Position” portion of the report. When I look to the Summary section to verify my “X” & “Y” values, they have been rotated to a different axis, which I don’t know how to explain away to those who may want to research the condition of their part. Saying “I don’t know, it just does that” doesn’t instill much confidence.
Am I missing something, or is this some kind of bug?
The Summary section is showing the XYZ values according to the datum reference frame, ignoring your alignment. If you have material boundary modifiers on any of your datums, this section will also show the datum shift, further throwing things off.
The Summary section is showing the XYZ values according to the datum reference frame, ignoring your alignment. If you have material boundary modifiers on any of your datums, this section will also show the datum shift, further throwing things off.