Actual vs Nominal Feature

[[Ro...]]

I am wanting the maximum and minimum point, from a 2d line. For the reference, should I be using actual or nominal? I see the default is actual, when using maximum/minimum coordinate. The results are also different depending on which selection is checked. I am wanting to think nominal should be used, but not sure of the difference, with regards to how calypso is doing the calculation.

[[Da...]]

Actual will be the measure values. Nominal will be the programmed values. You want the actual values.

[[Ro...]]

I thought of a test to try, before I saw your reply, and nominal was the correct choice, actually. I recalled every single point, from the line I had. I used result element to get the max and min of those points. They matched when I chose nominal for reference, instead of actual.

[[No...]]

The min/max points are calculated perpendicular to the reference. It depends on what you want to know. If the nominal line is parallel to X and task is to find the the point with the highest/lowest value along Y of the coordinate system, you need the nominal as the reference. If you just want to know min/max relative to the actual line, you need the actual reference.

[[Ro...]]

I saw something odd today when looking at results for the part I am on. The max coordinate was lower than the min. I am kinda confused now, on how this is being calculated. ❓

[[Da...]]

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From calypso 6.4 Help:
"
Maximum point construction:
Interpretation of results

As a result, CALYPSO calculates the coordinates of the point having the largest positive deviation (or, in the case of the stepped cylinder, the deviation to the outside). Depending on the selection, the result is a Point (with normal vector) or a 3D Point."

So if I am interested in Max deviation on Y axis, but I get bigger deviation of some point while scanning on X axis, will it report me the Y coordinate of the latter?
It is confusing to me also and I am still unsure if I am using correctly. If only I could find a good guide on this somewhere.

[[No...]]

Yes, I agree it's confusing. If you are scanning a circle and want the max coordinate in Y, then DON'T use a circle, because you won't get what you expect!
Use a line instead. That means use a circle for scanning, but then recall the points to a line along the X axis with a1/a2=0 (nominal). Don't worry about the funny actuals, they are irrelevant. Only the nominals are important. The line is just a means to tell Calypso how it shall calculate the min/max coordinates. In this case the reference for min/max must be nominal.

I remember somebody made an illustrated description of this in the old forum some time ago. I'll see if I can find it.

[[Ro...]]

So short of recalling each individual point, and using a result element to get the max/min coordinate, how do I go about getting what I am actually after? Max always seems to be the smallest coordinate, and the min always the largest, for the feature I am checking, regardless of which has the most deviation. For example.

Characteristic Actual Nominal Upper Tol Lower Tol Deviation

127 LLD Max 1 94.5941978 94.63 0.08 -0.08 -0.0358022
127 LLD Min 1 94.8628113 94.63 0.08 -0.08 0.2328113