probably try to ensure a reasonably consistent look and feel in similar documents. You employ consistent fonts, the same company logo, and the same paper size in most documents — or if you don’t, you probably at least think that you should!
CAD exacts similar demands for reasonable consistency, only more so:
? Most companies would like to take pride in the clarity and consistency of their drawings. Sloppy drawings with randomly varying text heights and lineweights don’t reflect well on you and make your drawings harder to read.
? CAD drawings that don’t conform with some logically consistent scheme usually are harder to edit and to reuse by others who work on the project and by you when you work on other projects.
This stuff is important enough in CAD that it has a special name:
Why CAD Standards?
Throughout this book, I emphasize things like setting up your drawings properly, drawing objects on appropriate and consistent layers, and specifying suitable text fonts and heights. These practices amount to conforming to a CAD standard.
You need to do these things if you work with or exchange drawings with others. If you don’t, several bad things will happen. You’ll be pegged as a clueless newbie by experienced drafters, who understand the importance of CAD consistency. Even if your ego can handle the contempt, you’ll make everyone’s work slower and more difficult. And if the project has electronic drawing submittal requirements, you may find that your client rejects your DWG files and demands that you make them conform to the CAD standards in the contract.
Even if you work solo and don’t have any particular requirements imposed from outside, your own work will go more smoothly and look better if you adhere to a reasonably consistent way of doing things in AutoCAD. You’ll certainly find plotting easier and more predictable.
CAD standards originally grew out of a desire to achieve a graphical consistency on the plotted drawings that mirrored the graphical consistency on hand-drafted drawings. Before the days of CAD, most companies had manual drafting standards that specified standard lettering (text) sizes, dimension appearance, symbol shapes, and so on. Sometimes these standards were based on standard industry reference books, such as the
As CAD users became more sophisticated, they realized that CAD standards needed to incorporate more than just the look of the resulting plot. CAD drawings contain a lot more organizational depth than printed drawings — layers, screen colors, blocks, xrefs, text and dimension styles, and the like. If these things aren’t subject to a modicum of standardization; then different people who work on the same drawings or projects are likely to end up stumbling over — or throwing things at — one another.
In short, the first job of CAD standards is to impose some graphical consistency on plotted output. CAD standards also encourage consistency in the way that people create, assign properties to, organize, and display objects in the CAD file.
Manual drafting veterans frequently complain that CAD drawings don’t look as good as the drawings that they used to create by hand. “Too ‘flat,’ too cartoonish, and inconsistent” are some of the refrains that you hear. These complaints are not just the whining of old-timers. Good manual drafters were justifiably proud of the appearance of their drawings. They focused on making the finished bluelines look sharp and read well.
When computers and CAD software got into the act, it became easy for CAD drafters to focus on the screen image and pay less attention to the plotted output. In the early days, CAD users struggled with a new way of making drawings and didn’t have as much time to make them look good. By the time that CAD became commonplace, a new crop of CAD users had grown up without the benefit of discovering how to make good-looking drawings on paper.
There’s no reason that CAD drawings can’t look as good as manual drawings. It’s a matter of understanding the look that you’re after and caring enough to want to achieve it. If you see some especially clear and elegant printed drawings, find out who drew them and take that person out to lunch. You’ll probably uncover some techniques that you can translate into making better CAD drawings. You may also gain new respect for the skills of those who made handsome and functional drawings with the simplest of tools.
Which CAD Standards?
If CAD standards are as important as I claim, you might expect that industries would’ve settled on a standardized way of doing things. No such luck. Although the manual drafting conventions in many professions have carried over to some degree into CAD, a lot of the things that need standardization have been left to the imagination of individual companies, departments, or people. For example, you’ll find that different companies usually name layers differently and employ different schemes for mapping object screen color to plotted lineweight (see Chapter 12). In particularly disorganized companies, you’ll find that different drafters use different layers and color-to-lineweight. And in the worst cases, the same drafter will do these things differently in different drawings!
As you can imagine, this proliferation of nonstandard standards makes sharing and reusing parts of CAD drawings a lot more difficult. You can at least minimize the pain within your own office by conforming to any existing CAD standards or, if there aren’t any, by encouraging the development of some. (Later in this chapter, I give some suggestions for how to get started.)
Professional, trade, and governmental groups in some industries have made an attempt to promulgate CAD standards for the benefit of everyone in the industry. For example, the American Institute of Architects (AIA), together with several professional engineering associations, published a
These documents may be useful to you in your search for standards, but they aren’t a panacea.
The majority of CAD-using companies has ignored officially promulgated CAD standards, because these companies developed their own standards and practices years ago and are loath to change. That doesn’t mean that you can’t use the officially promulgated standards, but they won’t suddenly make you a part of some mythical CAD standards mainstream. Also, practical implementation of most official CAD standards in a specific company requires a generous amount of clarification, modification, and additional documentation. In other words, you don’t just buy the document and then get to work; someone needs to tailor it to your company and projects. And finally, some of these officially promulgated CAD standards documents are shockingly expensive. Apparently these organizations
