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ANSI 1982 Datums


ANSI 1982 Datums

We just upgraded to Creo 6 (from 3.0). All our legacy data was made with datum callouts per ANSI 1982. (Datum under dimension).


One of my users reports trouble changing a datum to show this way. The datum in question is showing per ASME 1994.


The properties window for datums used to have this as a radio button, but that's gone now.


I also know there was once a config option (.dtl I think, but maybe .pro) for how datums are displayed, but I cannot find this option now.


Does this option still exist? If so, what is it? How do we show datum callouts under dimensions now. (Aside from faking it with the @[-A-@] cheat.)

23-Emerald II

The change was made in Creo4.

Asme Y14.5 for defining how datums are attached was revised in the 1994 spec. That spec is now 2 releases old as there have been a 2009 and a 2018 release. Not sure when PTC will support the 2018 spec in Creo, so we have only specified the 2009 release as being our standard.


I do have to ask the question: Why are you just now going to Creo6 when it is no longer supported since Creo7 is out? Creo4 and now Creo7 are the 'long-term' Creo installations, released every 3 years. The intermediate releases, Creo5 and Creo6, have a 1 year support window before being replaced with the next release.



Hi Ben,


Yeah, I know there are multiple updates since 1982. Unfortunately I operate in an environment where changes like that are presented as seismic and squashed. Personally, I wish we would update to a newer spec.


So 1982 is simply no longer supported? That's going to be a pain due to our latest contract.


I guess my message will have to be change to newer spec or fake it.


When I say we just updated to Creo 6, I don't mean that like "last week we updated". We actually scheduled and completed the update to Windchill and Creo before 7 was released. When things calm down later this summer, I'll update us to Creo 7. That's something I'll do myself, unlike the Windchill updates.

23-Emerald II

What version of Windchill are you on?


I cannot go to Creo7 yet as we are still on Windchill 11.0 and it does not support Creo7.

I wanted to wait and go to Windchill 12, but PTC does not support that upgrade option as they only support 2 versions, so 11.1 and then 11.2, for me.

I am working on the 11.2 upgrade now, trying to figure out what is needed. Windchill upgrades are fun! lol


We're on 11.1, for which the update was completed right around the time Creo 7 came out. It was on last-years budget or I might have delayed a little longer.


We always use a VAR for the upgrade as I'm dual function; Creo/Windchill admin and engineering manager. Plus, having never done it I can only imagine the kludge I'd make of it on my own.

On a side note, it should be possible to go from Windchill 11.0 to 12.0. You simply need to perform multi-step upgrade, where you go from 11.0 to latest version in supported upgrade path and then from that version to 12.0. In your case it would look like going from 11.0 M030 to 11.2 and then perform another upgrade from 11.2 to 12.0.
I recently performed an upgrade for the customer moving from 9.1 to 11.1, so it's doable, I just had to upgrade them to 10.2 first and then move from 10.2 to 11.1.
23-Emerald II

Well, yes, but that is still a double upgrade and a PITA!

That is the plan, go to 11.2 then12.0.

We just may stay on 11.2 for a few months.


I have been installing, upgrading and using Windchill PDMLink since 6.2.6 in 2003.

23-Emerald II

Can they eliminate the 1982 standard completely? I stil occasionally have to support drawings that have that standard applied.

I think most of those drawings were done way after the 1994 standard came out but still, I can't redo a drawing completely if the change doesn't pertain to the GD&T. 

If you change the drawing option GTOL_datums TO STD_ANSI, does that give you the old style datums?

Honestly, up until this point, I've been working with 1982 on our drawings and haven't had a problem. Most of our new drawings are copies of existing numbers, so that plays a big part.


I think this user just happened to be the first to encounter this. I worked on his file for an hour before posting this thread, including creating a new file from scratch. I simply wasn't able to get a 1982 datum to show up on either his file or on the new one.


It's easy enough to fake the 1982 datum flags, so it looks like that's what we're going to have to do unless everyone agrees to update to at least 1994. Unfortunately for us, we have some USG contracts that are still stuck on 1982 or, in on a few drawings, 1973. Updating those when the gov makes a revision is going to be... interesting.

Since my last reply, I've been giving the new method a go. I gotta say my impression so far is it's hot garbage.


Are there any tips or tricks that make this new method as easy as the old?

Hi @DonSenchuk 

I have couple of suggestions that might help in some cases:

1. If all you want is to Display the datum in the old ANSI 1982 way without having it really behave like the old datums that you could have placed on non geometry (e.g. mid planes) you can try and use the below display option for DFS. this might be obvious and already known to you, but I will mention it anyway, just in case



2. Also in case that you revise the GD&T in a legacy drawing/model to work per the new datum rules, you might want to consider using the Legacy Datum Annotation Conversion tool:


 This tool will be a good guideline for users who wish to migrate their old set datums to the new DFS datums, while keeping properly the relation between the new datums and the gtols that were previously referencing them (and keeping them associated)


I hope that this will help



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