Geometry or Free Form Surface

[[To...]]

The drawing calls for 2.000" Spherical Radius with a .005" Surface Profile to A B C. Should I be using the Sphere or the Free Form Surface for the feature in the Profile? For the record, I am recalling the feature points into the FFS. I am getting better results with FFS.

[[Ri...]]

I typically prefer the Geometry because I can apply Filter/Outlier if needed - very limited inside of FFS.

Having said that, make sure that the FFS isn't eliminating points via the "Point Elimination Activated" inside of the Evaluation tab.

Also make sure that your FFS is associated with the CAD model surface that applies to that feature.

[[To...]]

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Taking 22 touch points so filters or adjacent features aren't too relevant. Cad surface is selected.

I thought I heard something a long time ago about Profile on geometry, as opposed to a FFS, was based on the calculated feature and not the surface. So, in other words, if the 2" radius is reporting 2.010 on the sphere, is that affecting the results?

I just took a quick look at the evaluations in the two profiles and noticed the Sphere Profile was totally constrained but there was a Z best fit on the FFS Profile. However, the FFS Feature has no Best Fit active

FFS.JPGSphere1.JPG

[[Ma...]]

For profile callout where is fully defined alignment, then it can not be used any translation/rotation.
So it should be fully restricted as geometry is. Evaluation method should not do anything in this case.

So if scanned area is not more than 180° then any translation done on FF can change reported value.

[[To...]]

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Both profiles are fully constrained. Please explain why the free form surface is allowed to translate in Z.

[[Ma...]]

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It should not be allowed - all features should match profile callout datums ( aka A|BC ) with TED.
So it should be without any translation/rotation in this case.