How to measure symmetry of two points with MMR

[[Ma...]]

Hi i have this sketch and i am dealing with symmetry callout with (M).

My guess is using pattern of 6 symmetry points. Then using TruePosition.
But problem is i can not find a way to enable MMR.

Any hints?
Part has 6 teeth symmetrical by 60° and width is determined by basic dimension of diameter ( red color ).

[[Jo...]]

You could treat it as a position tolerance (actual symmetrie-point to ideal) with a non circular tolerance zone.

 

Edit:

Reading post again, this is what you allready tried?

Edited Monday at 09:59 AM

[[Ma...]]

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I think i have a problem only with (M) - can not enable it - not relevant dimension.

[[Jo...]]

Replicated the situation and ... what to use as linear element of size?

There is the witdh, but that is not the actually element the symmetrie or position is used on.

So basiclly i would say you can not represent it like it is put in the drawing.

[[Ma...]]

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I am able to obtain 2 points, but then i am lost.
So i think this is not correct drawing to norms.

I can report TP for all or individual ones after i fix rotation, but anything above tolerance i can not calculate.

[[Jo...]]

Got another idea.

Contruct circles from the intersection points of the teeth with the red circle and the symmetrie point of the pairs as center of the cirle.

The ideal size and tolerance of the circles would be the same as the width.

This way you got a elelement of size to use for postion with mmr, that in this scenario represents the same as the width.

 

[[Ma...]]

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I've tried circles.

I did center of circle from symmetry point, radius from point ( one of them )
This allows me to finally see GD&T sizes, but it can not calculate 2point distance, so still no MMR in that.

I wanted to use just 2 actual points to fit circle inside, but i can not do this either.

[[Jo...]]

You can`t use "Check Dimension (Independency Principle)" on the circles? Thats weird.

[[Ma...]]

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While this circle is "refferenced" then i am getting no result with warning.

Strange is, that in Calypso i can use Symmetry point ( not symmetry from points ) and it allows me to use MMC.

Edit:

The Scalar actual data missing

Edited Monday at 12:04 PM
Warning message

[[Ra...]]

This may also help. 

https://carl-zeiss-industrial-metrology-llc.helpjuice.com/zeiss_inspect/zeissgom-inspect-check-position-gdt-position-tolerance/version/1?kb_language=en_US

[[Ma...]]

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Thanks, but this is not helping in any way.

I was trying at home in free version 26 - only option is using 2d lines, so perhaps making it shorter could help.

[[Ra...]]

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My apologies, I copied the link to the wrong chat window I had up. for this,  I think the issue is not the construction itself, but that MMC/MMR requires a feature of size with an actual size value. The tooth center derived from the two intersections on the basic diameter is only a symmetry point and has no actual size. ZEISS INSPECT documentation states that material requirements require a dimensional tolerance on the element, and symmetry itself is generally not considered an MMC-applicable characteristic. Therefore I don't think INSPECT can represent this callout exactly as drawn. It may be a drawing-definition issue rather than a software limitation.

 

[[Ma...]]

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Ok, nevermind.

My question would be:

• Why can Calypso handle this with symmetry point and Inspect not?
• Why you can use pattern alignment in Calypso and same thing can not be done in Inspect?

I hope I know Inspect enough to ask those questions.
Only option to handle pattern of 6 points is using RPS. But then i have to make somehow alignment usable in callouts.

[[Na...]]

Good morning,

as

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 pointed out, a linear size is needed which cannot be calculated by two points in Inspect, Calypso seems to allow this.

You could create a cylinder based section through the part, so the section results in two sections per gear tooth which can be used to create two fitting lines -> symmetry line. Linear size is then possible and thus MMR. 

Alternatively this:

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A pseudo fitting circle must be created by creating a circle with radius by point (one of the points) -> Curve from 2D element -> use this curve as selection for fitting circle. 

 

 

[[Ma...]]

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Thanks, i'll look into it.

Problem is i can not fit width as stated by base circle/cylinder. I can get GG or MIN and MAX distance.
Tested with symmetry from two 2d lines and that worked.
Tested with circle, but i am not sure if i can use fitting circle from section to use only those two points - i think it will fit into section measured curve.

Any hint into pattern alignment? I don't think customer wants individual tooth to be evaluated separately - it will be machined, so i think he wants to evaluate symmetry ( or one axis TP ) on patterned alignment.
Good is that customer is not returning parts even if we are making them a few years.

[[Ma...]]

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So i've tested that circle.

As i thought - it was using whole section to calculate.

BUT - if i go to actual circle, constrain it's center point into symmetry point, deselect data and select only those two points, then projection into actual section plane, then it's calculating that circle from two points 🙂

But - is that correct? All hints are telling me it's using what it should be using 🙂

Edited 4 hours ago

[[Ma...]]

So using two points allows to create correct circle fails on GD&T size - so no MMR can be used

[[Na...]]

It should work if you use this function on the circle, then create a fitting circle from the curve:
https://techguide.zeiss.com/en/zeiss-inspect-2026/article/cmd_curve_create_curve_from_2d_geometrical_element.html

 

[[Ma...]]

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Thanks - that seems to work and it's much simpler instead of creating next elements just for makeing total of 4 points on circle.

So i'll create circle by center and point → refferenced constr. → create curve from that circle ( refferenced ) → create circle from curve ( fitting )

Is that right?

Next thing would be cluster i think - i hope i'll learn that too - it's so messy with naming
 

[[Na...]]

Yes, circle with size defined by the two points, and then a curve from that circle, which is used for a fitting circle. The linear size needs a selection like a section or curve.

Cluster is to copy elements and inspections so that would help to create elements around A for every tooth for example.