Surface Profile - Only 2 Datums

[[Ke...]]

I'm having an issue with Profile of a Surface.... and I suspect that Calypso is adopting the Base Alignment orientation.

Surface Profile Example:
Feature = Plane1

Primary Datum = Cylinder
Secondary Datum = Symmetry Plane
Tertiary Datum = Symmetry Plane
(all three filled out, otherwise no results - Changing the Secondary Datum to the Cylinder gets the same results)
Result = 0.758mm

Curve Profile Example:
Feature = Curve 1

Primary Datum = Cylinder
Secondary Datum = Symmetry Plane
Tertiary Datum = Not Required
Result = 0.2532

Relative to Base Alignment: Plane1 is approximately 0.29mm off nominal Z
Form of Plane 1 is approximately 0.08mm

I have Curve but NOT Freeform (yet), and the plant that I need to send the program to has neither Curve nor Freeform.

Am I correct in assuming that I/we need to have Freeform to evaluate this profile correctly?

Thanks,

[[Ro...]]

Hi Keith,
If Calypso isn't releasing the free DOF in the Profile characteristic you should be able to create your own Best Fit alignment and use that in the Profile Characteristic. Depending on your geometry, 3D Best Fit, Geometry Best Fit, and Alignment from Several Curves are all options that work well.

[[Pe...]]

I would evaluate it like:

Feature: Plane1

Primary: Cylinder
Secondary: Symmetry Plane
Tertiary: Plane1 (Same feature as being evaluated)

[[Ke...]]

Thanks for the input, guys.

Geometry & 3D Best Fit had results within a few microns of each other - I think Geometry is the better choice.

The issue with my first attempt of each was that the nominal locations for the alignment went back to the part origin, instead of the Datum AIB origin. So, I created a secondary alignment using AIB, and referenced the Geometry Best Fit alignment to that, instead of to the Base Alignment. The result was getting the correct origin (at AIB), and getting the exact same results as the original Surface Profile method (to AIBIB)... I think that the moral of the story is: Don't try using Curve Profile for a Surface Profile 🤣