Measurement of a Diameter on Cylinder

[Hirxm]

Hello so I’m really new to PC-Dmis. I have been working with some pieces but I’ve recently been asked to measure a diameter on a cylinder. But I have some doubts on how to approach this. I have attached a “drawing” I’ve made on my phone’s Notes app for “privacy” reasons hehe. On the picture, I want to measure the diameter of the blue circle.

My questions:
1. Do I need to align the part? If so, how do I do that? I’ve only worked with 3-2-1 alignments but I’m not sure if this would be ok with a cylinder since there is not a place where to place a line.
2. If the 3-2-1 alignment is not the answer, how would I align it?
3. Do I even need to align it? Or can I simply go straight to touch some points of the feature I want to measure and then measure the diameter on the software?

I have tried to measure it with a caliper but there’s too much variation.
Thank you, I hope you can help me.

[JEFMAN]

Very nice drawing !
I would say alignment is not necessary here, but if you're new to cmm, make it a habit to do it !
A cmm is not a calper that do "beeps".
The quickest way to do it is measuring a cylinder with a lot of hits, measuring the cut plane with somme hits, and create a circle at the intersection of both features.
Take care to dimension the cylindricity, it could explain variations with the caliper.

Then, another solution could be (which allows learning about alignments) :
In manual mode :
Measuring a cylinder, level Z on it and origin xy on it
Measuring the plane // to the cylinder axis, and rotate X on it
Measuring the cut plane and origin Z on it.
Re-do it with more hits for each feature in dcc mode, then create the circle by the intersection.

[AndersI]

The quickest way to do it is measuring a cylinder with a lot of hits, measuring the cut plane with somme hits, and create a circle at the intersection of both features.

What do you expect to gain by creating the intersection circle? The diameter of the created cylinder will be the same everywhere along the cylinder (ideal mathematical feature), so the circle diameter will be the same irrespective of where you create it.

I belive your second method is necessary (i.e. aligning to the cylinder and cut plane, and then actually measure the circle at the right place).

[JEFMAN]

Right ! Maybe my coffee wasn't enough strong this morning