FCF customized DRFs

[tami_]

Good day,

Running PC-Dmis CAD++ (2017)

Never really had the need to customize DRFs on TP or profile measurements since we had a technician that was doing that while proofing the programs (in medical devices) but now that has fallen on me since he is no longer here. I have looked everywhere for clarification about how the Customized DRF on xactmeasure actually works, no luck finding anything, Is there any available info on the forum anywhere I missed? When you customize the drf, does adding the x,y,z and u,v,w after a datum make the datum ignore it? That is the impression I have. I write the programs so I do understand the degrees of freedom and constraining them but if it ignores the items listed after the datums, which was my understanding, then some of them do NEED changed.

Thanks for any help!

Tami

[RanDawgg]

Adding the x,y,z and u,v,w in the reference frame means it DOES constrain those degrees of freedom. So if you don't want a datum controlling a degree that it normally would, input all of the degrees you want it to control, and leave out the degree you don't want it to. See figure 7-57 in the ASME Y14.5-2018 standard.

[tami_]

Thank you! I couldn't find clear info on that anywhere.

[AndersI]

Do note that the Help explicitly says that you must do an alignment matching the datums when using a customized DRF:

cdrfhelp.PNG

[tami_]

Do note that the Help explicitly says that you must do an alignment matching the datums when using a customized DRF:

cdrfhelp.PNG

Thanks .. starting to think our help files are broke because for the life of me, I could not pull that up with Search.

[sealevel]

The Customized DRF is a handy tool to show how Xact interprets your FCF. Sometimes what you think it should be is not (e.g: assignments to u,v & w)