As an aside, I disagree with the idea this is bad GD&T, knowing nothing about the part. I can see that curved surface resting on another curved surface, with the rails being there to begin creating a flat base. Fuselage, for instance.
In a case like that, the surface is absolutely the correct primary.
As an aside, I disagree with the idea this is bad GD&T, knowing nothing about the part. I can see that curved surface resting on another curved surface, with the rails being there to begin creating a flat base. Fuselage, for instance.
In a case like that, the surface is absolutely the correct primary.
if this were the case there should be some target points that this user could then iteratively align to
if this were the case there should be some target points that this user could then iteratively align to
As
DAN_M says - If you wanted to use this surface as a Datum then you would need to measure defined datum points on the surface (A1 , A2, A3) then perform an iterative alignment. Once the alignment is good you can define an Alignment plane as below, this can be defined as your Datum A in Xact measure. Of course you need more points for Datum B (2) and a point for Datum C to fully define the iterative alignment. HTH
