HELP WITH TRUE POSITION OF A PATTERN

[[Me...]]

Hey all,
I am having a rough time finding any info on how to properly use patterns as it pertains to true position. Do I use best fit of bore pattern? If i do what settings should be utilized and why. If I do a pattern i get weird results. If i measure a hole by itself i get answers that make sense. I want to use this function correctly as it saves me a ton of time. Any help would be appreciated. Thanks! Using Calypso 6.6

[[Br...]]

So what exactly are you trying to do? Do you have a pattern of holes that are referenced as a Datum? Or do you just simply have a position requirement on a pattern of holes?

[[Me...]]

Yes, Best Fit of Bore Pattern. Select your datums in the True Position dialogue. Select BF Bore pattern. In the BF settings, look at the bottom. You can constrain/unconstrain degrees of freedom. Release any DOF allowed by the print and hit calculate. The numbers shown are the allowable translation/rotation per your settings. Calculate again on the main window for True Position.

[[Me...]]

I have a position requirement as a pattern. What i'm struggling with is how to properly use the 4 settings to make sure I am getting the correct results. I measured a pattern of three holes and the results showed oot. when I measure them seprately they are well within and when I measure their location to each other linearly and angularly to the datums they are fine. So what did I do wrong in Bore pattern that gave me weird results? 😱

[[Me...]]

Need more information to help. Post a drawing/sketch of the features and how they are positioned relative to the datums.

Here's a common pattern I see. You have a set of holes on a plane, which is -A-. One side of the part is B, the side perp to B is C.
You have a composite FCF with the pattern to A-B-C and the pattern to A only.

First analysis is to A-B-C, which fully constrains the hole locations. You get no best fit. You can either check them individually in separate TP callouts and select the Datums in each one per the print, or use BF Bore pattern, select all the holes, but don't release any Translational/Rotational DOF. So when you calculate it in the BF Bore pattern window, the best fit numbers at the bottom will all be zero because there is no movement/fitting of the features.

Next is the pattern to A only. BF Bore pattern, select -A- only as a datum, and within the BF window where you select the features, check Translational and Rotational and calculate. The numbers shown will be the optimum translation/rotation to best fit the holes.

This is 2d Best fit for features on the same plane. There are other scenarios of using best fit of a pattern which I won't go into.

[[Me...]]

Okay that makes sense. My only question, is which best fit method should I use as default on something as you described. Gaub, Minimuum, View tolerance, or L1. I see the descriptions of each but i'm curious.