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EXTERNAL: Dimensioning Drafts


EXTERNAL: Dimensioning Drafts

Thanks Rob.

I agree 100%. Show dims save time but it’s not the only way.

I thought the world was against me when I suggested one option to create an associated dim, albeit without using a show dim J


Paul Mailloux ▪ Program Manager

NyproMold, Inc.

144 Pleasant St, Clinton, MA 01510 ▪

It is no extra work to create the dimension in the drawing and I have seen days wasted because a coworker insisted that all dimensions must be shown. Datums B and C were round locators molded into a very large plastic part, probably close to 1000 features. The locators had to be moved because of the mating part and almost EVERY feature had to be touched to make sure that when the locators moved the other features stayed where they were.

My overall preference when practical is to use the first 3 datums in the model which can never move. My main rule however is not to enforce any rules for dimensioning schemes. It usually depends on the feature purpose. That may or may not relate back to A, B and C.

Rob Reifsnyder
Mechanical Design Engineer/ Producibility Engineer / Components Engineer / Pro/E SME / Pro/E Librarian

At this point, I never use the 3 default datums for my GTOL datums. I always create datum planes where needed and then set those. Typically I try to make these the last features in the model.

When someone decided that they want that datum on another surface, it’s just a simple matter of redefining the placement of the datum.

No need to touch all the GTOL’s on the drawing or go through a bunch gyrations just to save them.

David Haigh

Excellent advice David, and my philosophy as well.


Brian Hasinger
Mechanical Designer
AIDA-America |<">>

Let’s face it. There are 3 camps of thought:

1) Created dimensions only

2) Shown dimensions only

3) Who cares…shown – created just get the job done
There are zealots on each side of this argument. I really do not think any one of the 3 is totally correct no matter what is said. I have my personal opinion which I will keep to myself.

I have been messing with Pro/E since rev 6. What matters is how does each individual company want their designs and documentation to be completed. Whatever that is follow their desire until you are working somewhere else where they want things done differently and then do it their way.

The exploder has far better things to offer the users who use it regularly than for another rehash of this age old argument. In all of the previous posting over all of the years the exploder has been in place I have never seen any new arguments for either side of this. I have been reading these recent posting in the hopes of reading some argument for either side I had not seen before. But I did not. With that said, can we please get back to where the real value is in this tool?

PS I love the exploder and read it every day…what a great tool. Thanks to all who have contributed some really great help and insightful information.

John M. Scranton
Ultra Electronics - USSI
4868 E. Park 30 Dr.
Columbia City, IN 46725-8869
•Voice: 260.248.3576
•Fax; 260.248.3509


I am always amazed that no matter what the topic of the original e-mail string is, once the first shot is fired across the bow about shown or created dimensions, the original topic is completely forgotten and we end up in a raging debate over dimensions. Obviously everyone is very passionate about this subject. The only thing that could make it better is if Republicans and Democrats weighed in with their preferences.

Tim Knier
QG Product & Support Engineering
A Subsidiary of Quad/Graphics
Sussex, Wisconsin
414-566-7439 phone

I never said you did the defaults-to-GTOL thing. Just pointing out another of the problems people create for themselves. IME, the best results have always been to create the GTOL datums right after the defaults and CSYS because if one is changing their GTOL datums, they are going to want to check every feature anyway to make sure everything is good to go.

I won’t disagree that the locator could be a GTOL datum. What I disagree with is that the GTOL datum is part of the locator feature. Make it a separate feature in the model tree. Then, if the locator has to change location, all the other features referencing that GTOL don’t get jacked up. Or if they would get jacked up because the GTOL is a child that moved with the locator (say, a GTOL axis that references an axis in the locator) it only requires redefinition of the GTOL back to its original position rather than redefinition of thousands of features. Separating it also makes it easier and quicker to find. As an added time saving bonus, users that have experienced this before will simply sever the one parent-child link before moving the locator in the first place.

I am leaving the political part of this message alone. Let’s just say that 2016 is just around the corner. There will plenty of talk in the other media houses.

23-Emerald IV

This really is very company specific. The first company I worked at NEVER used a shown dimension. There were a team of people who created the models and a different team of people who created the drawings. The drawing creators did not have permission to change the models at all. We were trained to use created dimensions. I didn’t even know you could show dimensions until I switched companies. We also never used the @O technique. I’m not sure anyone even knew about it….or if they did, they didn’t tell us!

The next company I went to almost exclusively used shown dimensions. They really wanted to be able to open a drawing and change the model by editing a dimension. Unfortunately this gets people in trouble because they often don’t actually look at the model to make sure nothing else was affected.

Now I tend to use a mix. If the shown dimension conveys what I want on the drawing views, then I will use it. If not, then I will create a dimension. (This happens a lot with sweeps and some with revolves.)

Tom U.
Business Continuity with Creo: Learn more about it here.

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