Opinions: Drawing Dimensions - best practice

I've not come to a decision yet - as different clients seem to each have their own ideas so, here are some alternatives I've had to deal with recently:-

A) Add all dimensions by manually inserting into each drawing

B) When building model check or uncheck "mark for drawing" and use "inset model items" to add dimensions. If more dimensions are needed go back to the model and add dimensions here - then re-insert model items.

C) When building model leave "mark for drawing" checked (default) and use "inset model items" to add all dimensions, then delete unwanted dimns.

D) Have a stab at the dimensions needed by checking/unchecking "mark for drawing" then delete any dimns not needed, then add manually any other dimensions.

I'm sure its horses for courses and depends on what the drawings are going to be used for - as my clients all have good reasons for doing it their way - but what do you guys think?

Kev

Reply to
alphawave
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I tend to use option D:-

I find it's better to hide rather than delete unwanted dimensions, because if you add further dimensions to the part which you need to show on the drawing, you will have to do another "insert model items" again which would re-create all the deleted ones again.

There are times when the most suitable driving dimension for the model is not the one you'd chose to show on the drawing, so I also add "superfluous" driven dimensions to the part which I mark for drawing.

The reasons I tend to use model dimensions is:- a) They are less likely to lose associativity to the model than drawing dimensions. b) It's useful to get in the habit at the modelling stage of considering the dimensions that will be used on the manufacturing drawing. c) When modelling the part, you often have to think about / look up / decide upon tolerances etc, and it's easier to add this info when modelling for recall on the drawing, rather than looking it up a second time later. d) SWX is crap about not letting you dimension to all sorts of silhouette edges, so you the model dimensions can be vital.

John H

Reply to
John H

Using model dimensions in a drawing is overrated. So is the ability to change models from drawings. More trouble than it's worth.

The important thing about a dimension is that it tells what it measures. As long as the dimension is associative (changes with geometry), it does not matter.

Most of my projects end up being dimensioned manually on the drawing. The reason is that the dimensions used to construct the model are not always consistent with the design methodology. Parts with lengths controlled by assembly context are better dimensioned manually. Locations of holes that are dependent on context often need to be dimensioned differently on the drawing for manufacturing purposes.

Reply to
That70sTick

Tick,

I'm with you. I've run into people who insist on using model dimensions, and who in fact have made it company policy to do it that way, but I never saw the point. I know "theoretically" its a great idea, but in practice it never works out that way. The way I model never has anything to do with the way a machinist or part checker wants to read a print, and I'm not going to try to model that way because an important feature might not be modeled until last for some reason.

Besides that, by the time you get done shuffling the dimensions around, and realizing that they aren't all there or that something is dimensioned twice, you might as well just put them on manually anyway. In fact, I'm just as likely to use the "Autodimension" to get things started because its more likely to be right for certain kinds of parts than using model dimensions.

Reply to
matt

I also almost never use model dimensions. They just don't often match the dimensions needed for manufacture, and I find it much quicker to add only the dimensions that I need rather than take the time to check/ uncheck the "mark for drawing" box. And I always miss a few and have to go back and find them or add them manually anyway. It would be nice, however, if the dimensions added in the drawing could be reassociated when the links break. UG has this feature and it makes fixing broken links a snap. I wonder if anyone from SW ever reads this newsgroup to see how users really feel (the SW forum seems to be primarily SW apologists).

Reply to
ed_1001

I with That70sTick, matt and ed_1001 for all the reasons they state.

I can't remember the last time I used "Insert Model Dimensions" on a drawing.

Regards,

Anna Wood

Reply to
Anna Wood

Kev, If enough people reply, you'll probably get answers to agree and disagree with A - D. I too agree with some of the comments so far and I also strongly disagree with many. Either way, here is my 2=A2: Because of the types of parts we predominantly create (machined) and the type of assembly modeling we use (bottom-up), we strive to use a vast majority of the model's dimensions. As a matter of fact, I teach & preach to model parts with manufacturing intent in mind. This is referred to as DFM (Design for Manufacture). We also employ DFA (Design for Assembly) for similar reasons. This goes back to the days when I was on a drafting board. You could not gain status as a designer, senior designer without knowing what manufacturing is all about. If you didn't know or learn manufacturing, you were a drafter. Machine & machine shop capabilities are key to a good design and therefore the manufacturability of parts. Additionally, ease of assembly and in some cases, only being able to assembly parts one way are also good design practices, When our drawings are complete, they are dimensioned with 95% model dimension. Reference and/or draft dimensions are used only when necessary. This methodology allows us to dimension once versus twice, make changes at the drawing level and it provides models (drawings) that are manufacturable. Does this work for everyone? No. Do we see it any other way? No. Eddie

Reply to
Eddie

Ditto to above

I've played with "Insert Model Dimensions" as it seemed like a great idea, but it always took longer. The other problem, I found (which maybe solved now), is after editing a model the inserted dimensions on the drawing moved and I ended up having to reposition them constantly.

John Layne

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Reply to
John Layne

I generally go with method A, adding the dimensions myself; part of the reason that I've never really thought about doing all my dimensioning in the model is that at both of the workplaces where I've used Solidworks, ordinate dimensions were standard practice. I'm not aware of a way to use ordinates when inserting model dimensions, and a quick look around didn't turn up anything obvious; does anybody know of one?

Reply to
Mark

As far as I can see, the only way to insert ordinate model dimensions is to create ordinate model dimensions.

Aaron R. Friedman ARF Designs

Mark wrote:

Reply to
Aaron

I too am all of the above. We very seldom model a part like it needs to be dimensioned. Some holes that are in context usually have no dimensions to them. The only time I ever import model dimensions might be for a round shaft that only has 1 or 2 dimensions but usually just put them in when doing the drawing.

Reply to
j

I'm convinced that the ONLY reason it was put in was it's a really cool demo feature. I'm with you, I don't ever use the model dimensions.

=========================================================================== Chris

Reply to
Chris Dubea

i always use model dimensions

one of the reasons is I dont like to do the work twice if ive dimensioned and tolerenced a model i dont then want to redimension the drawing it produces i kind of agrees with information "input"reuse

and i can pretty much do a drawing in half the time

If

Reply to
mikemcd

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