Topic: Getting to grips with dimmensioning

[hyposmurf]

OK Ive decided to take the plunge and learn dimensioning.Ive done the basics in my college course,but has anyone any recommendations or things I should look out for?What common mistakes are generally made dimensioning a drawing?What short cuts do you take?With my area of work I dont need to dimension my drawings as everything is drawn to scale,but this will just limit me when I go to look for another job.

[Rob_Kish]

Note that most print title boxes include the phrase: "Do NOT Scale Drawing"... which means (to the user) that measurements taken from a print are not likely to be accurate. Perhaps even in relation to other measurements on the print. This can happen if printer skews media as it feeds. So. Dims are Very important in any application that uses hard-copy drawings (such as most contracts).

AutoCad dimension commands are straight-forward, so I will take your post to mean what to dimension and how. How is best approached (these days) with reference to ISO equivalent of ANSI Y14.5M, "Geometric Dimensioning and Tolerancing" unless your field is AEC (in that case, see Architectural and/or Civil standards. Properly applied dimensions define all characteristics of the subject with only ONE possible interpretation. Mistakes? Under-defining or over-defining the subject, dimension references that are 'theoretical' (do not physically exist) and inappropriate accuracy specification (such as 14.444 degrees). The drawings must be usable in the field or shop.

[hyposmurf]

Yes Im talking generally about dimmensioning,what to & not to dimension,common problems and errors that users make,easiewr methods of working etc.I'd just like some insight from people who dimmension regularily.We only use dimmensions in our standards for  leader arrowheads.

[Dent Cermak]

The best test for dimensions in any field is to look at your drawing and determine if you can EASILY determine the proper cut length for every component in the design. Can YOU go into the shop or to the construction site and properly cut each piece to the correct size using the drawing. If you can't, neither can anybody else.
In my field, hard copies and paper prints are becommong a thing of the past. Most clients want the e-copy and measure distances directly, so drawing exactly to scale is becomming more and more important. I would predict that the only use for a plotter in the next 5 years will be for record copies and even those will be archived with an e-copy attached.

[CADaver]

OSNAP OSNAP OSNAP and one other thing OSNAP.

Taking the cue from you thread title, GRIPS are just too cool when relocating and editing dims.

One other thing OSNAP

Something that may draw some fire is Annotation in PS.  Try it you'll like it.

[hyposmurf]

That was an accidental cue! Thanks for the response.I noticed that by resizing an object the relevant dimension will reassociate to,so If you dont use your snaps and the line becomes offline from the original,your dim line doesnt show the correct dimension.So CADaver you're right.A serious thread from Dent,I was just waiting for the pun somewhere. .If anyone else has any more suggestions I'd be grateful.

[Artisan]

One thing that helped me over the years was viewing examples of work that had been done previously. I work in the residential field, so my examples were floor plans. I just paid attention to what I was doing and tried to put myself in the shoes of the framers and others on the job. I was lucky in that I had a great example to work from when I started. I am sure a few of the guys here would be happy to provide you with some examples to get you started.

[Bob]

Try not to get the message of the drawing confused. Leave yourself a good amount of room around your component so that your dimensions are not too close to the component.

Most important remeber your %%c (or diameter) and other little notations which help the machine shop. Eg. A/F for across flats, O/A for overall.

Finally, if it looks right it will be right. If you can get your hands on an old copy of BS308 (this has been superseded by a million ISO standards) it will give you an excellent pointer in the right direction.

[Dent Cermak]

Hyposmurf, it was just TOO easy to throw in a comment along the line of "I don't care what your girlfriend says, that's not 500 cm!", so I kept it serious. Believe me, everybody else here read that in as the underlying statement. Didn't ya'll !

[PDJ]

If you explode dimensions, you will DIE!!

The same goes with hatching..

I can forgive maybe 2% of your dimensions being exploded, that is ALL!!  I can NEVER forgive exploding hatching.. ESPECIALLY if you're using 2005!

[whdjr]

I would just like to REiterate what CADaver said earlier.

OSNAP! OSNAP! OSNAP! OSNAP! OSNAP! OSNAP! OSNAP! OSNAP! OSNAP!

   

[CADaver]

oh, and another thing, OSNAP.

[PDJ]

Ohh, and spell check too.. Dimensioning only has 1 m...

OK, O'Snap too..

[hyposmurf]

Great I have enough to go on now from here. .I think the hardest part is arranging the dims so they dont clash with leaders etc and totally confuse the drawing.Yes exploding anything that doesnt need to be exploded is a PITB.Would anyone be able to upload a drawing please that has many dims on,just so I can get an idea of laying out my dims?

[Bob]

Have a look at this http://www.theswamp.org/lilly_pond/bob/R20041106_S01_R-23.dwg?nossi=1

and this

http://www.theswamp.org/lilly_pond/bob/R20041108_S01_R-23.DWG?nossi=1

or this

http://www.theswamp.org/lilly_pond/bob/R20040194_S01_R00.DWG?nossi=1