Calypso Cylinder Question

I have a question for those of you who have Calypso experience. When a cylinder is measured in Calypso and used as a translational origin of the Y axis, where along the axis of that cylinder will the origin be placed? Will it be at the top, middle or bottom (point 1,2 &3) of the cylinder? See my creation for more detail on what I mean. Is there a way to create a cylinder with point 2 Y-Origin. What is the default location?



I'm having some measurement differences between my program in PCDMIS and the customer data in Calypso. My nominals all come from the intersection of A and B which gives the correct print nominal. The customer is seeing about .5mm difference in the Y axis. If I pull the nominal from the cylinder at the # 2 point location and insert that into their data then our measurement deviations are very similar. Just an observation i had made and before i go questioning anyone i like to do a little bit of homework.