abc alignment x value is different than true position x value

[[Ma...]]

I have a drawing that asks for a x value of a feature and also a true position. (They should have made the x value s basic dimension) So I clicked the x value and got a value.

Then saw the true position callout and dimensioned true position with xz values.

I got a difference of .005 between the result of true position X value and the feature X value. Both base alignment and true position datums identical.

Also tried various evaluation methods and getting significant variation.

It does not make sense to me. Any thoughts??

Running Calypso 2024 on a Contura with VAST XT.  I've tried different evaluation methods and all show different results.

[[Ma...]]

It depends on a feature. Non perpendicular plane, cylinder, maybe others will result in different value then just reporting X,Y,Z value.

Also often TP will report doubled value for cylindrical tolerance.

[[na...]]

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Try to find topics on the forum, talking of how to pull value from position.

I know they exists, I just can't get it now.

[[Cl...]]

Is it a diametric true position callout? If I'm understanding the question correctly, It could

have a third toleranced axis. I'd have to see the drawing to be sure.

[[na...]]

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Try to adapt what Phillip answered -> https://qualityforum.zeiss.com/topic/12522-bore-pattern-best-fit-additional-info/?do=findComment&comment=62730