Plane line point vs plane plane plane

It really depends on what features are Datums and what the Feature Control Frame describes on the print. My reply was strictly about a 3 plane alignment, assuming ABC are planes. There are a lot of different datum structures and I'm sure many people will provide their version of what they believe is best practice. A manual alignment is pretty wide open. I, personally, use a single point alignment and then I pick up my Datums or part features twice in DCC to remove as much vector issues as possible. Our CMMs run 24/7 so it is all about having the operator do as little as possible. You can do a full 3-2-1 alignment in manual and you would only have to pick up the features one more time in DCC. As far as how to construct datums, I recommend checking out ASME Y14.5-1994 or above. It goes into more detail than you could ever want, but they essentially use what I described before, max inscribed holes and ID cylinders, min circumscribed OD circles and bosses, and describe what to do if the Feature Control Frame constrains less than 6 degrees of freedom. I also recommend formal training with Hexagon. They give you books you can bring back to work with you that, combined with the standard, will help both of you create your own best practices.

It really depends on what features are Datums and what the Feature Control Frame describes on the print. My reply was strictly about a 3 plane alignment, assuming ABC are planes. There are a lot of different datum structures and I'm sure many people will provide their version of what they believe is best practice. A manual alignment is pretty wide open. I, personally, use a single point alignment and then I pick up my Datums or part features twice in DCC to remove as much vector issues as possible. Our CMMs run 24/7 so it is all about having the operator do as little as possible. You can do a full 3-2-1 alignment in manual and you would only have to pick up the features one more time in DCC. As far as how to construct datums, I recommend checking out ASME Y14.5-1994 or above. It goes into more detail than you could ever want, but they essentially use what I described before, max inscribed holes and ID cylinders, min circumscribed OD circles and bosses, and describe what to do if the Feature Control Frame constrains less than 6 degrees of freedom. I also recommend formal training with Hexagon. They give you books you can bring back to work with you that, combined with the standard, will help both of you create your own best practices.