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Can Ordinate Origins Be Basic?

Question asked by Brian Dalton on Nov 9, 2015
Latest reply on Nov 10, 2015 by Ed Cyganik

We have a pattern of holes which are located using ordinate dimensions.  Their tolerance zones are specified using a position tolerance frame, so the dimensions themselves are basic.  I have left the origins (sometimes called the base) of the ordinate dimensions as plain numbers, without a rectangle around them.  Another engineer insists that because the dimensions themselves are basic, the origin must be too.


This does not make sense to me, since the point of a basic dimension is to represent the theoretically exact location of a tolerance zone, but the origins (being the reference points from which the dimensions are measured) have no tolerance zones.


The image shows the situation: the upper version is correct in my view, the lower is what my comrade prefers.  Which is correct?