STEP AP242 and semantic references

[Pettersson]

Hi, everyone. I thought Creo 9 supported semantic references when exporting to STEP AP242 format, but when trying it myself I couldn't get it to work. When I finally looked at the video in the "What's New" documentation and tried to replicate it, I got it to work, and I suddenly realized that the text was carefully written to only mention "notes" (though the title was "Improved STEP AP242 Support for References Included in Annotations").

So just to check that I'm not missing anything, for people who have more insight into this than I have: Creo 9 only supports semantic references in STEP export for note annotations, and not for dimensions, geometrical tolerances, etc.? Really seems strange to me; I would have thought that it would be just as easy to implement this for any kind of annotation, so this omission sounds unnecessary. But then I'm not a programmer.

[AchrisK85]

I have no further insight, but I am curious about how exactly you are verifying the application of semantic references. So you have a model in which annotations such as driving and driven dimensions, notes, GD&T annotations, etc. had been set up with sematic surface references. Then you exported to STEP AP242. What application did you then open the STEP file with to verify?  

[Pettersson]

I used Creo 9. I.e. I opened the STEP file in Creo directly after exporting it. I had three different annotations: a (driven) dimension, a geometric tolerance and a (leader) note. When I exported to STEP and imported it back into Creo, the semantic references were there for the note (not just the surface the leader is attached to, but another "extra" surface, too), but they were not preserved for the dimension and the GTOL.

[AchrisK85]

Thanks for the info. Where I work I believe we have evaluated Creo STEP AP242 creation in Creo the same way, but I am not sure that is an effective way to understand the situation. That process includes both STEP export and import, and once imported into Creo, you are no longer looking at the STEP file, but a .prt file that results from an imported STEP file. Thinking about it that way it is possible that the Creo STEP export or import functionality, or the combination of the two, could be the problem.

Don't get me wrong, I am no expert on STEP AP242 or STEP exports in general. But I wonder if there is a better way to open and evaluate a STEP file export in its native format.

[StephenW]

Re-opening in Creo gives a "hint" at what you are dealing with and is by no means a comprehensive evaluation.

For a specific company, the ideal evaluation is to view the step file as it will be viewed by the intended recipient. If there are multiple recipients with potentially multiple viewers, you should evaluate as many as you can and then offer suggestions to the recipients your "approved" or "preferred" viewers.

The technology is developing and capabillities are expanding, I doubt there is one simple solution.

[Pettersson]

Yeah, there's no specific company here. I'm trying to understand what functionality Creo actually supports. I first assumed all semantic references were supported, but when testing it myself found that this doesn't seem to be the case. I find the release notes almost "sneaky", implying that it works for all annotations, but carefully worded to not mention anything but notes. So I thought maybe if someone already knew the answer. Not trying to fix a problem, just understand how well Creo 9 supports STEP AP242

[AchrisK85]

Got it. Excellent topic and questions. I think a lot of us are in this territory right now, trying to figure out exactly where our companies are in implementing MBD/MBE, and at the same time trying to figure out how well PTC is supporting those needs. 

[BenLoosli]

Have you looking in the STEP file in a text editor. STEP files are just plain text. Look for the text string that was in your original file and see if that information was written to the STEP file. This should help determine if the issue is on the export or the import side. If you have access to a different CAD system, try the import to that one may also give you some direction.

[StephenW · Accepted solution]

This may be your answer from PTC or at least helpful Step Analyzer

https://community.ptc.com/t5/System-Administration/Cannot-open-large-STP-file-Creo-not-responding/m-p/895933/highlight/true#M30020

[Pettersson]

This was a neat little tool; thanks for the tip! I tried it on my model, and sure enough, it seems to me that the note carries the extra geometry, but the other two annotations don't.

In the screenshot below, we can see that the note has two planes in the "Associated geometry" column: 2974 and 3432. The flatness and position tolerances both point to the exact same two surfaces in Creo, but only one is listed here (2974). The "linear dimension" is only associated with the edge that it measures, whereas in Creo I added various surfaces as supplemental geometry.

My conclusion is that in at least this instance, Creo 9 only supports semantic references for notes and not for other types of annotations. Of course, this was just this model, and it would be nice to actually have a text from PTC saying what is supported, but looking at the "What's new" section in the documentation, seeing how it's carefully worded to avoid mentioning annotations in general (except int he title) and how only a note type annotation is demonstrated in the associated video, it seems reasonable to conclude that this is not implemented.

Thanks for your help!

[JohnIngalls]

The 1st post points to this one as "Solved."  I disagree.  It even says:

"My conclusion is that in at least this instance, Creo 9 only supports semantic references for notes and not for other types of annotations. Of course, this was just this model, and it would be nice to actually have a text from PTC saying what is supported..."

[JohnIngalls]

This is a serious issue.  STEP AP242 is designed to include semantic PMI in exchanges.  This holds-back industry progress to move toward more 3D-annotations for use across the entire MBE life cycle (not just design).  We've done similar testing at our site, like the author did, with similar results, and found other issues with Creo's import/export of AP242.  As mentioned in other posts here, more testing is needed to determine where exactly the problems occur.  PTC should be testing this, or clearly publish info on what works or doesn't (or maybe we haven't found the right documentation), in each Creo version.

This and similar topics came-up at the last PTC conference in the Data Exchange session, which prompted the restarting of the Technical Committee for Data Exchange https://ptcusergroups.ptcuser.org/organization/tc-data-exchange-archive/dashboard .  I'm going to add this PTC Community thread link to the list of reference info in the TC.