Is this important?
I would imagine so, considering all the parts have datums, but what is the difference from, say, setting a point as Datum A and dimensioning a feature to Datum A, and setting a point and dimensioning a feature to said point?
If you use legacy, (as you answered the "left" picture above" then defining datums is pointless, as you won't use them. If you are aligning to your datums and using legacy dimensions, then you are already "defining" the DRF (Datum Definition is a particular thing in PC-DMIS, it has a meaning, that is not how you are using it).
I'm not going to answer rotary table questions, since I never use one.
Based on the answer to my question above, you do not need to use the PC-DMIS function "Datum Definition". However, when you say you've "seen" the other window, what do you mean? I'm asking because if you go to Insert...Dimension...Location, it looks similar to the left window, but if you went to Insert...Dimension...True position and it looks like the one on the right, you do have Xact measure turned on.
If you go to Insert...Dimension, and look at the very bottom of that sub menu, is the a check box next to "Use legacy dimensions"
You do still need to do a proper alignment, however. As an aside, "Datum Definition" does NOT create an alignment, it only defines what the feature the datum letter is.
