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Tangent Point - actually Cosine Error from incorrect IJK vector

I've a question about how the CMM calculates hits on tangent points. In the attachment I have a picture showing the issue.
I have 2 lines. Y is vectored with straight on hits. X is also vectored with straight on hits.
Since X- is not a 0/45/90 degree angle, but at a 20 degree angle form a straight on hit, will the ball calculate slightly off as it thinks it makes contact at 0 degrees, but actually hits earlier at 20 deg. thus creating the line 0.096mm sooner than it should have?

It obviously figures this out with circles/cones/cyliders, but it doesn't seem to do this with lines and points.
Should this be planned for and the measurement offset in calculation, or can it be corrected with some really specific (and tedious) vectoring so the probe knows where it should be hitting?



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  • You can also use sample hits and PCDMIS will calculate the angle of the surface and compensate the probe radius accordingly no matter what theo vector is for the feature.

    Any explanation from the manual ?
    For example: I have a circle on a plane 40 degrees with horizontal surface on the CAD, if the part is only 39 degrees with base surface, 3 sample hits will compensate this 1 degree cosine error ?
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  • You can also use sample hits and PCDMIS will calculate the angle of the surface and compensate the probe radius accordingly no matter what theo vector is for the feature.

    Any explanation from the manual ?
    For example: I have a circle on a plane 40 degrees with horizontal surface on the CAD, if the part is only 39 degrees with base surface, 3 sample hits will compensate this 1 degree cosine error ?
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