I have a bore that is Datum B. It has a perpendicularity callout to Datum A, which is a flat surface. So, I have to measure it as a cylinder. I have another bore that has a circular runout callout to AB. So do I have to measure B again as a circle? Because I would have to assign that as another datum to build the feature control frame. But if I just use B as a cylinder, then wouldn't it be measuring total runout and give me a different result than circular runout?
This is what you should see when trying to select a cylinder (CYL1) as the considered feature and a plane (PLN1) as the primary datum. Notice the error message stating the need for an axial DRF.
Adding a secondary datum (CYL2) defining the centre of rotation makes the callout valid...
However, you can not just arbitrarily decide which feature to use as your secondary datum, you need to talk to the designer (or whoever gave you the drawing) to establish what they intended and get their agreement/permission on whatever final approach you take.
This is what you should see when trying to select a cylinder (CYL1) as the considered feature and a plane (PLN1) as the primary datum. Notice the error message stating the need for an axial DRF.
Adding a secondary datum (CYL2) defining the centre of rotation makes the callout valid...
However, you can not just arbitrarily decide which feature to use as your secondary datum, you need to talk to the designer (or whoever gave you the drawing) to establish what they intended and get their agreement/permission on whatever final approach you take.
I see now. If you were using Legacy, and, for example your alignment was A/B, A being a plane and B being a bore, would you just output runout to the origin, or would this not be feasible in Legacy?
