Cant use modifiers because i rotate the trihedron?

[[Ri...]]

This isn't making sense.
Datums are C, A and B
C is a plane in -X (Primary)
A is a cylinder on C (Secondary)
B is a cylinder on C (Tertiary)

Customer wants the Trihedron rotated so +Y axis is in +X, +Z is -Z. (see Rotated Trihedron)
When I set up the True Position, the modifiers are enabled. (See Non Rotated Trihedron)
Once I rotate the Trihedron to be like what the customer wants, the modifiers are disabled. (See True Position Rotated)

Why would rotating the Trihedron affect modifiers?

True Position Rotated.PNGNon Rotated Trihedron.PNGRotated Trihedron.PNG

[[Lo...]]

I had to recall Cylinders as circles to get MMC/MMB to work at all.

[[Ri...]]

It works with cylinders until I rotate the trihedron. 🙄

[[Da...]]

Firstly, I would check the nominals of all involved elements. Are the nominals of all the cylinders parallel?

[[Ma...]]

How you want to report X Z when -X is your base plane? YZ make sense

[[Ch...]]

As a shot in the dark : have you tried :

filling out the datums and roating, THEN adding the feature after ?

[[Ri...]]

Use a Bore Pattern instead, it will work.

If A&B are parallel to each other on the same plane, then Calypso will not use the cylinder of B as the Tertiary.

[[Ch...]]

or Geometry Best Fit if needed...

I almost never use a cylinder as tertiary. I will measure 2 or more times if needed.


Good Luck !

[[Ri...]]

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The only problem with Geometry Best Fit is that you absolutely cannot do any MMB/LMB evaluations then.

You can use the Parallel Cylinder feature - it will allow MMB/LMB.

[[Ri...]]

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I am just showing different scenarios, where I can and can not use modifiers.

[[Ma...]]

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I wanted to point that Plane2_C with other elements gives some alignment on base alignment - so only rotating base alignment can be used.

As far as i tested - you had to click "special" to rotate. Perhaps now Calypso don't know how to mix axis of elements with MMx
You can not recall feature to rotated alignment, since it's doing no change to axis on TP report.

[[Ri...]]

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Good point.
I will try creating Theoretical Circles from each cylinder and see if it allows modifiers.

[[Ri...]]

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I don't think it will matter if it is a circle or not.

Try a Bore Pattern instead.

[[Je...]]

There are several things at play here;
1 - using cylinders (especially parallel ones) for your secondary and tertiary datums can cause problems if there are not proper intersections to restrain to. I try to stay away from using cylinders and 3d-lines for alignments and TPs where ever possible. (an axis changing direction has the tendency to waste days of troubleshooting time tracking down the culprit for inconsistent movements and values)
2 - In order to utilize MMC/MMB, first you must have all features in the TP characteristic with the same space axis.
3 - All those features must also be reporting in the same translational DOF coordinate system as they are measured under.

Once you rotate the trihedron you remove Calypsos ability to translate the features in their feature coordinate system for calculation. Calypso then simplifies to using the feature as a 3d point that is no longer a feature of size and therefore no means to "shift" (in a nutshell for in calculation).

As a test, rather than rotating the trihedron in the TP char, try changing the alignment of the feature to the same space axis orientation as your reporting TP char. Can't remember if this works but you may be able to use recalled features from the originals so you don't have to make program changes but I cannot verify that without testing myself.

[[Ma...]]

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I did try that - made new rotated alignment, recalled feature to new alignment then used all features in new TP, but something happened and it was back to original.

Initial in beginning it was reporting XZ instead of YZ, but after cylinders it was back to YZ. Don't know what happened.