Dimension formula

[steelcom]

Hello all,

I would like to change the dimensions measured by 1/2" on panels measured within our acad drawings as we order materials 1/2" shorter. To date, we manually dimension each item drawn several hundred times and decrease the dimension by 1/2" again and again. Obviously, this is not efficient and prone to human error. Can anyone tell me the lisp code or alternate method to do this? I've researched this and it generally becomes an argument as to why anyone would want to show an inaccurate measurement without an answer. As a side note, I don't really have any practical knowledge of lisp files as I'm just learning about them.

[Dadgad]

Welcome to CADTutor.

 

Most accomplished users have a profound disdain for overriding dimensions, because it seems to imply/invite/embrace poor drawing habits, which can be a very slippery slope.

Are you at liberty to post a sample of this type of drawing, so we can take a look. There may be a very simple solution at hand which would be preferable to overriding. A dynamic block may be a good way to go too, but we need more information.

 

A lisp could certainly be of help, and that is not what I am alluding too, as I am incredibly lisp grateful (thanks Lee Mac! ), but personally "illisperate".

Be that as it may I would love to see a sample, from which you could probably delete the majority, and any proprietary information, just leaving enough to give a better idea of the task at hand. Not a PDF, but a .dwg would be most useful.

[danellis]

Could you use a field that display's under the dimension (like an alternative unit would) and refers to the measured value: This would have the advantage of changing with the drawing.

 

 

dJE

[steven-g]

I would personally do that at ordering stage with a formula in an excel sheet. If you go into the dimension style manager and in the tolerances tab - set the method to limits and then upper value=-1/2" and lower value=1/2". It will at least not involve overriding dims and it shows a double value to give a visual clue that the dim is altered

[steelcom]

Great. Thanks to all for the responses. I'll post a sample file later today to clarify the need. Steven-g, your idea is close and something that we've tinkered with but it still shows the original, "correct" dimension and confuses the installation crew and clutters the drawing.

[steven-g]

Not if you set upper to negative, it does show 2 dims but both the same,

[ReMark]

I would never want to confuse a contractor by giving him a correct dimension. It just encourages accuracy. LoL

[Dadgad]

I would never want to confuse a contractor by giving him a correct dimension. It just encourages accuracy. LoL

 

Touche!

[steelcom]

See, this is what I mean. You're connecting the dots before collecting all of the dots. You're throwing barbs at an issue without seeing or knowing it as a whole. We order and install materials 1/2" less in dimension because we need the tolerance and the panels are not meant to be installed as a perfect tight fit. The 1/2" less measurement allows for ease of installation. Kindly respond with help or stay out of the conversation.

[ReMark]

So you take great pains to draw the panels accurately then override the dimensions because they cannot be installed accurately. That seems unusual.

[steelcom]

No. We draw our columns accurately on the framing grid lines and are installed as such. The metal panels are actually drawn inaccurately as a byproduct of showing them drawn from column edge to column edge, when in reality they are not. The metal panels are attached to these columns (horizontally) but are ordered and installed at 1/2" less than the out to out dimension of our structural grid lines for ease of installation. Now, obviously I could add additional lines to offset the framing lines and show accurate panel lengths but this in itself is tedious. The simpler solution, I think, would be to change the output of the dimension for these panels. Please keep in mind that these panels occur hundreds of times throughout the drawing.

[Dana W]

How about a dynamic block for a panel which can be stretched in two directions if need be. Dimensions can be included that are offset 1/2" in whatever direction you choose when constructing the block. The dimensions will stretch with the panel. Then you don't have to draw any of them, simply place and stretch to size.

[Dana W]

See, this is what I mean. You're connecting the dots before collecting all of the dots. You're throwing barbs at an issue without seeing or knowing it as a whole. We order and install materials 1/2" less in dimension because we need the tolerance and the panels are not meant to be installed as a perfect tight fit. The 1/2" less measurement allows for ease of installation. Kindly respond with help or stay out of the conversation.

If you come to this forum without time for humor, you will be spending a lot of time irritated. Now, that's what I call helpful information.

[RobDraw]

it generally becomes an argument as to why anyone would want to show an inaccurate measurement without an answer.

 

This should tell you something. Maybe you need to rethink how you present your drawings. If you are dimensioning the space that the panel goes into, then it needs to be noted as such and instructions given as to how the panels are to be constructed. This can be done with detailing or some sort of schedule. I'm having trouble with understanding why you don't just draw them correctly in the first place.

[nukecad]

I'm having trouble with understanding why you don't just draw them correctly in the first place.

Seems quite simple to me:

 

Steelcom is dimensioning the openings into which the panels fit.

He wants to call-out and order the panels themselves 1/2" smaller than the opening.

 

You could just add an addendum (DIMADD) saying something like "Opening size - cut panels 1/2" smaller" to your dimension style?

Of course that gives a potential problem of risking somebody getting the deduction wrong every time a panel has to be cut.

 

To do it correctly you would have seperate drawings of the panels, at the correct sizes, for the panel cutter to work to.

 

It's the old trade off-

If you want to save yourself time then let someone else do the calculation, and risk it being wrong.

If you want it to be right everytime then do the extra drawings.

[RobDraw]

His first post alludes to drawing them. I found it obvious that his dimensions are for the opening and stated as such. I was wondering why, if he is indeed drawing them, that they are not drawn to size. Especially since the dimensions need to reflect the actual size.

[steelcom]

The issue is expediency. You guys get bogged down wondering why someone wants to save time not drawing the panels to the accurate measurement without answering the question. Of course we can offset the grid lines a quarter inch a thousand times on a drawing and clutter it up or simply deduct the measurement by 1/2" and use that as our material list and callout to the installer. The materials are not cut in the field but cut in our factory, thousands at a time. I get it. You guys use ACAD for accuracy but trust me on this one. I'm simply looking for a quicker way to determine the dimension of the panels, which is 1/2" less than the out to out measurement of our framing grid lines every time.

Dana W, I do think that you're onto something and it seems that it will work. Thank you for both tips.

[RobDraw]

I'm not trying to nit pick, but if your dimensions are measuring the space, why draw the panels? AutoCAD has always been known for it's accuracy. If you are not utilizing that in your particular trade, IMHO, you are doing it wrong.

 

Can you post an example of your drawings, so that we have all the dots? Someone may have a methodology and/or code that will suit your needs.

[ReMark]

Just add a note stating that the finished panel sizes do not reflect the actual dimensions and have been intentionally under-sized, when ordered, by one-half inch to facilitate installation. Done. Nothing else required of you. Just make sure the note is large/bold enough that no one who reads the drawing(s) can say they did not see it.

[RobDraw]

Just add a note stating that the finished panel sizes do not reflect the actual dimensions and have been intentionally under-sized, when ordered, by one-half inch to facilitate installation. Done. Nothing else required of you. Just make sure the note is large/bold enough that no one who reads the drawing(s) can say they did not see it.

 

I'd also include a mounting detail showing that 1/4" offset from the grid line, or even better, showing what the panels are mounted to. I'm still very curious as to what is being drawn and why thousands of them need to be dimensioned, if they are mass produced.

 

Who is counting them? Is it automated and scheduled into a BOM?

 

Too many open questions.