Edit Technical drawings thoroughly
August 27, 2009 7:19 AM   Subscribe

I’m looking for help with how to edit my technical drawings more thoroughly.

I am currently working as a drafter for a company that installs and sort of manufactures specialized equipment for theater. My college majors were theater and computer science, which means that I understand how our equipment functions and know how to use AutoCAD. But that my training in drafting conventions was a little fast and loose. We use a 2D cad software so one of the problems I’m having is adjusting things in one view and then forgetting to make the same change in a another view (i.e. changing the height of something in elevation and then forgetting to look at in section.) Does anyone have any recommendations on how to look at your drawings as if for the first time and edit things better? My brain tends to tell me that things look fine if I’ve seen something , multiple times even though it is no longer the correct solution. Or know of any resources for learning construction standards for drafting conventions (revision cloud notations and the like?).
posted by edbles to Work & Money (6 answers total)
Does your company have a standard drawing checklist? We have one that I run through every single time I make a change to a drawing (well... I try :). Coincidentally some of the first items on the checklist is "Are changes made in one view propagated to all views?" and "Are changes made in one part propagated to all parts?" If they don't, then I suggest writing one up, based on input from the people who review your drawings.

Another technique I use is to constantly print out and red-line drawings physically, then print out a copy with the changes and compare them to the red-lines I made. I catch a lot of errors that way, compared to just making the changes in the soft copy without any physical documentation. In other words, I plan out any changes thoroughly even if they're just based on a short ECO.

I can't help you with construction standards - if y'all are using ASME Y14 drafting standards then we use the Drawing Requirements Manuals listed here, but your company may want to follow different standards.
posted by muddgirl at 7:39 AM on August 27, 2009 [1 favorite]

Should be "Are changes made in one part propagated to all assemblies?"
posted by muddgirl at 7:57 AM on August 27, 2009

It's good to have someone else look at your prints to keep such things from happening. If you're the only drafter then this gets difficult, but someone else at your firm needs those prints and they are your best resource for helping you see your drawings afresh.

If there is a construction-line facility in your CAD package you can draw some of those and inspect the print with the construction lines on and off.

If you are running AutoCAD (R) you can use Lisp to drive dimensions and have Lisp read a spreadsheet to automate the placement of features or components. It's only worthwhile if you have standard parts and you are simply re-arranging them. I believe canned packages exist to do this as well, but haven't ever used any.
posted by jet_silver at 8:32 AM on August 27, 2009

jet_silver is right that you really need a thorough review process on every drawing from another set of eyes. I've been professionally drafting as an engineer for 4 years and I don't think I've ever sent a perfect drawing to review, no matter how much time I put into it. I like to have another drafter or engineer and the person who's gonna be building the system review my drawings several times.
posted by muddgirl at 8:40 AM on August 27, 2009

If you don't have checklist, at least make a separate layer (not to be printed in final set) that's available for you to make notes on the fly. Make it something visible when you're printing your check sets.

If you're having difficulty in figuring out what changes will impact other things, then having at least a note of what changes have happened since the last version will help when reviewing with someone else.
posted by mightshould at 10:44 AM on August 27, 2009 [1 favorite]

Thanks all around. I think I am going to take action on all of your advice by making an official checklist block that lives on a layer I can turn off when I hit the plot a set of submittals stage. But I think that I need to take the step of actually going through a physical checking off process instead of doing a soft mental one electronically before handing it off to a project manager. Also it was helpful to know that even people who've been doing it for 4 years still have d'oh moments.

To answer some questions that were posed if it is at all helpful. I'm the only drafter although a project manager usually reviews my drawings. We're using AutoCAD LT so unfortunately LISP scripts won't be that helpful. I long for real CAD, but we probably don't really need it.
posted by edbles at 7:28 PM on September 1, 2009

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