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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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  • This feauture, iterate and repeirce, is intended for situation where you are measuring a complex surface with constantly changing surface normal directions. In this situation a small difference in the measured location of a point can have a significant impact in the probe radius compensation. To mitigate this sensitivity to the exact location of each measured point the iterate and repeirce function will shift the measured points around to find the best fit to the CAD surface in order to get the best possible probe radius compensation and most accurate surface profile value.

    With a hole pattern you are dealing with simple geometry and there is no issue with unpredictable probe radius compensation. There are tons of options for creating best-fit circles that do not involve this iterate option at all. My recommendation is that you research the best practices for measuring circles and cylinders (there are a million threads about this) and stay away from iterate and repierece, which is really a tool for free form surfaces.
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  • This feauture, iterate and repeirce, is intended for situation where you are measuring a complex surface with constantly changing surface normal directions. In this situation a small difference in the measured location of a point can have a significant impact in the probe radius compensation. To mitigate this sensitivity to the exact location of each measured point the iterate and repeirce function will shift the measured points around to find the best fit to the CAD surface in order to get the best possible probe radius compensation and most accurate surface profile value.

    With a hole pattern you are dealing with simple geometry and there is no issue with unpredictable probe radius compensation. There are tons of options for creating best-fit circles that do not involve this iterate option at all. My recommendation is that you research the best practices for measuring circles and cylinders (there are a million threads about this) and stay away from iterate and repierece, which is really a tool for free form surfaces.
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