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Ten Tips For Effective Electronic Drawing

You e-mailed your drawings to the CAD firm days ago for inclusion in a set of master drawings. Why are they taking so long to make a few modifications and get back to you? What was that remark from accounting about an extra charge for the work, and what's this lawsuit all about? The efficiency and security of electronic drawing will forever remain outside your grasp unless you follow a few key principles.

You e-mailed your drawings to the CAD firm days ago for inclusion in a set of master drawings. Why are they taking so long to make a few modifications and get back to you? What was that remark from accounting about an extra charge for the work, and what's this lawsuit all about?

The efficiency and security of electronic drawing will forever remain outside your grasp unless you follow a few key principles. The following 10 tips will help you do just that. You may find it best to incorporate these over weeks or months, rather than all at once. As you continue to work with electronic drawings, you'll discover some tips of your own. Keep a running list. One trick that works well is organizing your tips in a plain spiral notebook.

For the more digital among us, it can be more helpful to keep a spreadsheet or database of tips and insights. Arrange this information by category, so you can refer back to it quickly. Here are 10 tips to get you started.

Tip 1: Use layers and name them with forethought. Create different layers for your drawing. By using separate layers for electrical system components, such as receptacle circuits and lighting circuits, you create an easier-to-read-and-understand drawing. Do you want heightened efficiency? Then name those layers based on what they represent.

For example, if all lighting circuits in a drawing are on a single layer, you may want to name that layer "lighting." The same holds true for data lines, control wiring, or whatever the drawing represents.

You might want to put your wireway home runs on their own layers. Or you may want different sizes of wireway on different layers. Rather than name a layer "2 1/2 EMT," name it "EMT_2-1*2." By putting "EMT" at the beginning of the layer name, you keep all of your EMT layers together. Never put a space, slash, or backslash in the name of a layer or file (slashes and backslashes connote path names; spaces create confusion).

Tip 2: Practice font simplicity. At some point, it's likely your drawing will go to a third party. Don't expect anyone to have more than a few basic fonts, much less some obscure one. Use common fonts, like Arial or Times New Roman, when creating a drawing.

Also consider the font's impact on the user. You can give a person vertigo by using too many fonts. Use one font for your logo, a second for your title block, a third for your drawing text, and a fourth for dimension labels. Anything beyond that is pushing it.

Tip 3: Break a large drawing down into a set of continued pages. Some drawings tend to get overcrowded. Don't fall into the trap of making a drawing useless by overloading it. Remember: White space is important.

Some Windows-based drawing applications allow you to hyperlink a point of your drawing to another page, file, or web page. By doing this, you can create "drill-down" type drawings that allow you to click on a drawing entity to link to an expanded view. For example, a person may look at an entire floor plan at the first level, then click on a particular office or wing of the building to see a detailed plan of that area.

This helps make a drawing more of a manageable tool, rather than a cumbersome and complex collection of lines and symbols lost in a sea of other lines and symbols. However, there is one drawback to using hyperlinks: They use system resources and may degrade system speed to an unacceptable level. So use them sparingly.

Tip 4: Keep the drawing's purpose in mind. Try to keep the drawing focused on the original intent. This means don't add information that does not support that intent. Avoid getting carried away with the amount of data the drawing tries to communicate.

One way to put this strategy into use is to create multiple versions of the same drawing. Let each version communicate with a different focus or aspect of information. For example, you don't need to show enclosure dimensions on a wiring diagram, though you might show them on a switch mounting drawing. Use separate versions for the dimensions and wiring diagrams. This is easy to do without redrawing. Simply create a drawing with multiple layers. Then, make layers visible if they add to your focus or invisible if they don't.

Tip 5: Use standard symbols. If you want to drive an electrician completely crazy, use nonstandard symbols. This is one of the major complaints electricians have about the drawings they get these days. No one wants to learn a new language with every new project; nor should they have to.

Clear and effective communication reduces errors, delays, and cost overruns. This is why industry groups agree on standard symbologies for representing specific items.

It's worth the small investment to obtain an electronic library of symbols. Then you don't have to draw them from scratch. For a work group situation, this is usually the only sensible approach.

Tip 6: Use grids, snaps, and constraints. Drawing "off grid" slows down a work group. Eyeballing the placement of an object or the connection of two lines creates a sloppy drawing that's hard to modify later. For one thing, it'll be hard to click precisely on a line that's in a random location rather than based on a grid. (Editor's note: This writer worked with a set of such drawings. To add the electrical, he had to completely redraw the architectural. This resulted in a cost overrun, even though half the rework hours were free.)

Many CAD "tricks of the trade" depend on precise location of objects and precise endpoints of lines and arcs. Drawing freehand makes these timesavers useless. For a professional look and the ability to make changes quickly, also place your text "on grid."

Tip 7: Follow the conventions for showing connections/non-connections. Two intersecting lines represent a connection only if you place a dot at the intersection. If you break the lines to show a non-intersection, you are showing broken wires, not a non-intersection. Drawing a hump in one of the non-intersecting wires is acceptable, but not preferred. Why? Because when someone scans the drawing with the eye, the hump stands out. It's also one more entity to add to a drawing.

Because the dot is so small, placing it "on grid" is critical. Not all printer drivers will interpret the dot position in the same way, relative to the line intersection. Thus, you could print out a drawing that shows a bunch of dots intermingled with lines that don't appear to make electrical connections. In other words, you'd be the victim of the absolute versus relative reference problem. If you specify the line intersection as the center of the dot, you will get a correct printout every time.

Tip 8: Control your revisions. If a drawing needs some level of access control, set it up as "display only." Then, you should allow editing access based on user passwords or profiles. This allows a work group to share a drawing, but limits revision making to those who are qualified.

You could also make the original drawing "display only," and set up a new revision layer that's "unlocked." This way, team members can add annotations to that layer without affecting the original.

Tip 9: Use title blocks and borders correctly. Use title blocks to identify pertinent and useful information. Put in what drawing users will need, but limit title blocks to what is useful. An enormous logo, names of company officers, and lists of other drawings don't go there.

Keep this area clean. A simple, sans serif font (like Arial or Helvetica) is all you need in the title block. To save time, examine what portions of it are the same on every drawing. Then, make a special drawing with just that information. When you make this drawing, you'll want to include the whole drawing border in it. You'll need a vertical and horizontal version for each drawing size.

(Editor's note: Deborah Atherton, a mechanical engineer and CAD wizard in Dallas, set up such borders as hborda, vborda, and hbordb for "horizontal border a-sized drawing," "vertical border a-sized drawing," and "horizontal border b-sized drawing," respectively. This applied across the entire spectrum of drawing sizes, which went up to E-size.)

Tip 10: Make sure you apply file security. In these days of rampant corporate espionage, Intranets, and digitized sensitive information, security is a major issue. Suppose you're doing the startup of a conveyor system for a food plant, and your drawings show the entire process. Your client's competitor might blunt your client's competitive edge with this information. Or maybe your drawings show the power distribution system, security system, and other information a terrorist could use. You get the idea. How do you protect your client?

Some companies use advanced document management systems to help keep corporate documents and drawings secure. Some drawing programs support standard document management protocols, such as ODMA (Open Document Management Architecture). These protocols help track revisions, monitor document access, and provide version control.

You must develop a comprehensive plan to address everything from virus scans on incoming drawings to paper shredding of plots and printouts. Somewhere in that plan, you must address controlled access to the drawing files. Not only must you focus on the physical security issues, but you also must highlight the password, system administration, and other software-based issues.

Since security and encryption are fast-moving fields, you should bring up these issues with your software vendors. If you have a secure system, make sure you have someone assigned to monitor for update notices via the Internet, e-mail, or phone calls to vendors. What worked to keep your data secure six months ago may be obsolete now.

TAGS: Design
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