I have been trying to figure this out for literal hours. I'm trying to understand how PC DMIS calculates flatness so I can defend it to colleagues and prove it trustworthy.

My issue is it doesn't make sense. My min and maxs are the EXACT same except for one is positive and one is negative. No way do I trust that. I don't understand where PC DMIS gets the deviation from, it doesn't make any sense. I took a total of 33 random points. I created a plane, leveled and origin-ed in the Z to that plane, then constructed the Flatness. I read somewhere that if I turn on textual analysis on the flatness and then create a location in the Z and turn on textual analysis of the same plane it should be the exact same min and max between the plane and the flatness so long as I level and origin to the plane first. But they're way different and again for the flatness my min and max are the same in the positive and negative which can't be possible. For the plane location I'm getting a max of .002639 and a min of -.003453: the xyz of the max is .666883, 1.250651, .002369 and the xyz of the min is .648687, 1.493985, -,003453. So the deviations for that make sense, it's the z values of the xyzs of the max and the min. For the Flatness, the max is .002711 and the min is -.002711. Why are they so different from the location max and min? In the plane, none of the deviations seem to correlate to the xyz values or anything else. The max and min of the flatness plane are the same as the location so I don't know why I'm getting two separate deviations. I don't understand the deviation the plane is giving me, for the min it's saying a -.002711 deviation but the z value is .003453 and the max is a .002711 deviation but the Z value is .002639. Where does PC DMIS get the deviation of .002711 from? That's what I don't understand and can't figure out and it's driving me crazy. My understanding is that the deviations should be the same for the location and for the plane but they aren't, they aren't even close. If I do the math using the max/min of the location of the plane I get a flatness of .006092 but the Flatness PC DMIS is giving me is .005422. I know the difference isn't huge but I want to know WHY I'm getting a different deviation for the flatness xyz values than the plane xyz values. Where does PC DMIS get a deviation of -.002711 when the actual Z is -.003453? How does that make any sense? Am I missing anything?

I hope that makes sense, I'm kinda frazzled after trying to figure this out for hours. I feel like I'm so close to understanding how PC DMIS creates the flatness and I'm so close to convincing my coworkers to trust the dimensions given but I don't understand the deviations and I don't know why I'm getting the same number in the negative and the positive for the Flatness call out.

My issue is it doesn't make sense. My min and maxs are the EXACT same except for one is positive and one is negative. No way do I trust that. I don't understand where PC DMIS gets the deviation from, it doesn't make any sense. I took a total of 33 random points. I created a plane, leveled and origin-ed in the Z to that plane, then constructed the Flatness. I read somewhere that if I turn on textual analysis on the flatness and then create a location in the Z and turn on textual analysis of the same plane it should be the exact same min and max between the plane and the flatness so long as I level and origin to the plane first. But they're way different and again for the flatness my min and max are the same in the positive and negative which can't be possible. For the plane location I'm getting a max of .002639 and a min of -.003453: the xyz of the max is .666883, 1.250651, .002369 and the xyz of the min is .648687, 1.493985, -,003453. So the deviations for that make sense, it's the z values of the xyzs of the max and the min. For the Flatness, the max is .002711 and the min is -.002711. Why are they so different from the location max and min? In the plane, none of the deviations seem to correlate to the xyz values or anything else. The max and min of the flatness plane are the same as the location so I don't know why I'm getting two separate deviations. I don't understand the deviation the plane is giving me, for the min it's saying a -.002711 deviation but the z value is .003453 and the max is a .002711 deviation but the Z value is .002639. Where does PC DMIS get the deviation of .002711 from? That's what I don't understand and can't figure out and it's driving me crazy. My understanding is that the deviations should be the same for the location and for the plane but they aren't, they aren't even close. If I do the math using the max/min of the location of the plane I get a flatness of .006092 but the Flatness PC DMIS is giving me is .005422. I know the difference isn't huge but I want to know WHY I'm getting a different deviation for the flatness xyz values than the plane xyz values. Where does PC DMIS get a deviation of -.002711 when the actual Z is -.003453? How does that make any sense? Am I missing anything?

I hope that makes sense, I'm kinda frazzled after trying to figure this out for hours. I feel like I'm so close to understanding how PC DMIS creates the flatness and I'm so close to convincing my coworkers to trust the dimensions given but I don't understand the deviations and I don't know why I'm getting the same number in the negative and the positive for the Flatness call out.

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