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Surface Profile - Iterate and Repierce function

Can someone give me a rundown of what the iterate and repierce function does? I turn it on and all of a sudden my surface profile improves significantly. Is that real?

On a similar topic, has anyone else had trouble with vector least square best fit causing a best fit error? I have had several parts now that had profile dimensions set to vector best fit, which runs fine offline, that have given me best fit errors at the end of the program. If I hunt down the offending dimension and change it to least squares the error goes away immediately. I have also had a similar problem if I set the iterate and repierce function with too small of a tolerance. I'm using an .039 (1mm) ruby and have found I need to set the repierce tolerance to at least .025 to reliably run through the program without any best fit errors. This seems to be related to features with very large radiuses of contour (almost flat, but not quite). My assumption is that the math runs out to too many decimal places and it can't handle it.

Thanks for any advice. I am inspecting a part that is just one giant contour, no flats at all, and need to have all of my ducks in a row around how all of the surface profile options work.
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  • I'm fairly new to programming. Been working on it for about a year, but I have only been to the level 1 classes. I've been wondering about the iterate and repierce function in the best fit alignment. I see the discussion here has primarily been about using it for surface profile, but what are your thoughts on using it for a best fit hole pattern? I have a part with a constructed primary datum plane. It sits slightly differently on the fixture every time it runs, and there's no avoiding that. I do not use an iterative alignment on the part because I really don't know what I'm doing there, but best fit for hole patterns I think I understand. I actually want pcdmis to move my points around on the cad model and find the best fit. If I don't check iterate and repierce the measurements are in on some parts, and slightly out on others, but all of the parts drop on to our hard "bed of nails" gage with no problem. Could iterate and repierce be what I need to get the correct the results? Sorry if this is a "noob" question, but I haven't seen a lot of posts on iterate and repierce and hoped I could learn from this one.
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  • I'm fairly new to programming. Been working on it for about a year, but I have only been to the level 1 classes. I've been wondering about the iterate and repierce function in the best fit alignment. I see the discussion here has primarily been about using it for surface profile, but what are your thoughts on using it for a best fit hole pattern? I have a part with a constructed primary datum plane. It sits slightly differently on the fixture every time it runs, and there's no avoiding that. I do not use an iterative alignment on the part because I really don't know what I'm doing there, but best fit for hole patterns I think I understand. I actually want pcdmis to move my points around on the cad model and find the best fit. If I don't check iterate and repierce the measurements are in on some parts, and slightly out on others, but all of the parts drop on to our hard "bed of nails" gage with no problem. Could iterate and repierce be what I need to get the correct the results? Sorry if this is a "noob" question, but I haven't seen a lot of posts on iterate and repierce and hoped I could learn from this one.
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