I have a part that is 115 inches long and has a primary datum feature that is essentially a small segment of an enormous arc. Secondary and tertiary features are both holes drilled on the primary feature. I started with an iterative alignment to synchronize the part and model and then probed points on datum feature A, measured circles datum B then C. I then constructed a plane from datum A, defined my datums and used XACT measure to report other hole positions relative to ABC.
I feel I did this wrong... due to constructing the plane from datum A as the true vector of the constructed plane can incorporate additional error (or so I've read). I know there may be a few ways of doing this but what would be your ideal way of inspecting a part like this? Every feature on the part was relative to this datum structure.
I started with an iterative alignment, took a few points on the end faces, the edges of the part and top of the part. After this could I have just created a vector least squares best fit alignment to the primary feature (then exit best fit window) and origin to B and rotate to C?
In the beginning (after creating an iterative alignment) I tried to constrain rotation of X and Y and translation on Z with the points probed on datum A but i was not successful (not sure why), since I don't use the best fit alignment much.
(to better visualize this part, this pretty much looked like a 115" long by 8 inches wide, .500 thick with holes on it BUT it was formed, carbon fiber, and primary datum is irregular/banana shaped)
You could also just do an iterative alignment with the vector points on the Datum A feature surface (and the B and C features). Then there's no need for constructions. Although, that does not work if you want to use XactMeasure. Then you need to follow Anders' suggestion.
Nice. Thank you. I've been a bit skeptical about directly measuring from an iterative alignment but I see where it's beginning to serve its purpose, I usually only used it as a "rough alignment". So if I used the best fit method, and iterate to the measured points, then pcdmis uses the fitting algorithm (in this case vector least squares) go align 3Dimensionally?
Nice. Thank you. I've been a bit skeptical about directly measuring from an iterative alignment but I see where it's beginning to serve its purpose, I usually only used it as a "rough alignment". So if I used the best fit method, and iterate to the measured points, then pcdmis uses the fitting algorithm (in this case vector least squares) go align 3Dimensionally?